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Flurries
On Thu, 4 Jan 2018 22:27:41 -0500, "Mr. Luddite"
wrote: On 1/4/2018 6:01 PM, wrote: On Thu, 4 Jan 2018 13:01:34 -0800 (PST), Its Me wrote: That's because electricians are schooled on the mechanics of wiring, but not theory. If a device's tag says it draws 30 amps, they know what size and type wire for the run to it (or where to look in the NEC book to find it), breaker size and type, conduit or not, etc. I'd bet close to half don't understand that the two legs are actually 180 degrees out of phase. Their exposure to theory is very brief, then it moves on to mechanics. Nothing wrong with that. The book tells them what size neutral, too. :) That was true in places where training is left to the unions but places that get actual continuing education for the new guys (and the old guys) will be exposed to a lot more theory. Union training is basically the old guys dribbling out what they know to the new guys over 4 years. Very little new ever penetrates that cycle. I remember trying to explain triplin harmonics to a bunch of union GSA electricians and having them tell me how long they had been wiring and how I was just a snot nosed kid who didn't know ****. A week later when their neutrals were burning up, the manager told them they needed to listen to me. Nobody had ever seen electronic ballasts and switching power supplies before the 70s and 80s but they learned. I am sure some electricians do learn theory however I agree with Its Me. When new stuff comes along the code is just rewritten in terms of how to wire for the new stuff. The code tells them when arc suppressors are necessary, for example, but the electrician doesn't necessarily know why. I have a fairly solid understanding of electrical wiring and power distribution. However, I am totally ignorant of what current building codes are. I wouldn't even consider doing a new residential service or even a major renovation of an existing service myself. I'd hire a licensed electrician. I can't speak for the mobbed up union states but I changed from the inspector trade association (IAEI) to the contractor group (ECF) many years ago and I talk to those guys a lot. (they are more fun) They get a lot of basic theory in their CEUs these days and I have never met one of them who was confused by neutral loads. It is dealt with extensively in NEC articles 215 and 220. These are generally the license holders but we also see a lot of journeymen. |
Flurries
On Thu, 4 Jan 2018 22:45:25 -0500, "Mr. Luddite"
wrote: On 1/4/2018 7:43 PM, Alex wrote: Mr. Luddite wrote: On 1/4/2018 1:07 PM, John H wrote: On Thu, 4 Jan 2018 12:42:29 -0500, "Mr. Luddite" wrote: On 1/4/2018 12:20 PM, wrote: On Thu, 04 Jan 2018 08:54:03 -0500, John H wrote: On Wed, 3 Jan 2018 17:19:35 -0500, "Mr. Luddite" wrote: On 1/3/2018 2:28 PM, Its Me wrote: Light flurries now, the predictions range from a dusting to 1-2 inches.* Worse the closer to the coast you get.* My BIL at James Island (Charleston) sent a picture earlier of maybe 1/4 inch and still falling.* Very unusual for them. It's out of here in a few hours and headed up the coast.* Good luck! Damn.* I was hoping it would dump a foot in Mt. Pleasant, just to shut my son up. Last I heard it is supposed to "explode" as it comes up the coast, becoming essentially a winter hurricane. "Bombogenesis" is the technical term, and the popular "bomb cyclone" is a shortened version of it, according to our weather folks. They do seem to just make up names for things these days. I think the classic was "Super Storm Sandy" to talk about something that was not even a hurricane, it was just "super" for people who were not used to tropical weather. It is far from unprecedented tho. There was a real Cat 3 there in the 30s. I have certainly seen that weather pattern in DC tho and this is not even the worst case. The snow would actually be more of a problem if the "eye" of that low was farther west so your wind was drawing wet gulf stream air up into the cold front north of you. That is what gives DC over a foot of snow a day and if it stalls, you "Knickerbocker" snow. Up here a Cat 1 hurricane in the summer might be preferable over what is going on right now. When you look at this storm on radar it is developing a very defined rotation as it is winding up and getting bigger.* Snowfall rate here is 2-3 inches/hr and the temp is dropping like a rock since this morning.* Pretty much a white-out out there. Major flooding in Justin's former town with 4 disabled cars with people trapped inside, one a woman with 2 kids.* Water is over the wheel wells. * Fire and National Guard are responding. My old stomping grounds in Scituate is really getting clobbered ... worst in over 30 years despite improvements in sea walls, etc.* A TV reporter nut was standing on the porch of a house about 30 feet from the seawall and he was getting soaked with spray, along with dodging sea ice that is being thrown up onto the roofs of houses. So far we haven't had any power glitches here but I fully expect we'll lose it in the next hour or so. Wind where I am is gusting 55-60 mph. Best of luck in all that. I think I'd be getting out the extension cords and prioritizing my electricity requirements! Did that yesterday ... that's why I was firing up the Honda to test. I have a new plan.* If power goes out I am going to shut off the main breaker and then backfeed the generator output through a 15 amp outlet that's in the shed.* It's on the same branch of the split 240v house supply as the furnace and a couple of rooms.* All my lighting is LED, so that's a tiny load.* The generator will run those plus the furnace system with no problem and I don't need to have extension cords running anywhere. Only problem with that is it's hard to tell when the power is back on. Turn off the breaker that feeds the shed, turn the main back on and see if your lights work. If so, shut off and unplug the generator then turn the breaker that feeds the shed back on. When Wilma hit in Florida I had a much bigger contractor's generator that had a 240 volt split phase output. I wired it into the power panel (illegally) on the load side of the main breaker and just made damn sure I didn't forget and turn the main back on. It worked fine except it burned so much gas I would have run out of my supply in a matter of a couple of days. Only used it for about an hour or less a day to run the well pump and the water heater so I could take showers. Other than that, I used the little Honda for the refrig, couple of lights, the TV and Direct TV receiver. My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) |
Flurries
On Thu, 4 Jan 2018 22:48:47 -0500, "Mr. Luddite"
wrote: I didn't know it was illegal - at least not here.* If you are effectively, and correctly, taking yourself "off the grid" you should be able to do whatever you want. It's illegal everywhere I know of ... meaning "not to code". As someone mentioned there's a risk to line workers who are restoring power if you stupidly leave the main on while using your generator. I suspect they are careful to check for "hot" lines that are supposed to be dead though. Since the codes are usually adopted as law, that makes it illegal. I agree the power crews should be using safety procedures that prevent them from getting killed but people screw up. You are more likely to get your neighbor who is screwing around trying to get his gen set going with a suicide cord or worse. I was amazed at the things people were doing around here. One guy was so far out of whack, I told him to stop trying to feed his panel and just use cords. He is a fireman/paramedic who should know better too. In retrospect I think he had a generator that did not have the neutral bonded, using an existing cable that assumed they were (only connecting to the generator ground). His neutral to the panel was floating. He had already blown some stuff up by the time I got there. |
Flurries
On Thu, 4 Jan 2018 22:50:19 -0500, "Mr. Luddite"
wrote: Harry's playing outside, four wheeling in his driveway in 4 inches of snow. Ny niece posted a picture on Facebook of a measured 6" a few miles south of Harry. He may have more than 4" of snow. |
Flurries
On Thu, 4 Jan 2018 22:52:39 -0500, "Mr. Luddite"
wrote: Don't know if it's still so but I remember in the old days you could remove the battery from a car once it was running and it continued to run just fine. They always warned you not to but I did it on my 69 Corvette and nothing bad happened. (dead battery, no cables and a borrowed battery to get it going) OTOH a new outboard (Yamaha or Mercury) will stop right away if you disconnect or even have an open cell in a battery. (over voltage) BTDT ... twice. |
Flurries
On 1/4/2018 11:54 PM, wrote:
On Thu, 4 Jan 2018 22:45:25 -0500, "Mr. Luddite" wrote: On 1/4/2018 7:43 PM, Alex wrote: Mr. Luddite wrote: On 1/4/2018 1:07 PM, John H wrote: On Thu, 4 Jan 2018 12:42:29 -0500, "Mr. Luddite" wrote: On 1/4/2018 12:20 PM, wrote: On Thu, 04 Jan 2018 08:54:03 -0500, John H wrote: On Wed, 3 Jan 2018 17:19:35 -0500, "Mr. Luddite" wrote: On 1/3/2018 2:28 PM, Its Me wrote: Light flurries now, the predictions range from a dusting to 1-2 inches.* Worse the closer to the coast you get.* My BIL at James Island (Charleston) sent a picture earlier of maybe 1/4 inch and still falling.* Very unusual for them. It's out of here in a few hours and headed up the coast.* Good luck! Damn.* I was hoping it would dump a foot in Mt. Pleasant, just to shut my son up. Last I heard it is supposed to "explode" as it comes up the coast, becoming essentially a winter hurricane. "Bombogenesis" is the technical term, and the popular "bomb cyclone" is a shortened version of it, according to our weather folks. They do seem to just make up names for things these days. I think the classic was "Super Storm Sandy" to talk about something that was not even a hurricane, it was just "super" for people who were not used to tropical weather. It is far from unprecedented tho. There was a real Cat 3 there in the 30s. I have certainly seen that weather pattern in DC tho and this is not even the worst case. The snow would actually be more of a problem if the "eye" of that low was farther west so your wind was drawing wet gulf stream air up into the cold front north of you. That is what gives DC over a foot of snow a day and if it stalls, you "Knickerbocker" snow. Up here a Cat 1 hurricane in the summer might be preferable over what is going on right now. When you look at this storm on radar it is developing a very defined rotation as it is winding up and getting bigger.* Snowfall rate here is 2-3 inches/hr and the temp is dropping like a rock since this morning.* Pretty much a white-out out there. Major flooding in Justin's former town with 4 disabled cars with people trapped inside, one a woman with 2 kids.* Water is over the wheel wells. * Fire and National Guard are responding. My old stomping grounds in Scituate is really getting clobbered ... worst in over 30 years despite improvements in sea walls, etc.* A TV reporter nut was standing on the porch of a house about 30 feet from the seawall and he was getting soaked with spray, along with dodging sea ice that is being thrown up onto the roofs of houses. So far we haven't had any power glitches here but I fully expect we'll lose it in the next hour or so. Wind where I am is gusting 55-60 mph. Best of luck in all that. I think I'd be getting out the extension cords and prioritizing my electricity requirements! Did that yesterday ... that's why I was firing up the Honda to test. I have a new plan.* If power goes out I am going to shut off the main breaker and then backfeed the generator output through a 15 amp outlet that's in the shed.* It's on the same branch of the split 240v house supply as the furnace and a couple of rooms.* All my lighting is LED, so that's a tiny load.* The generator will run those plus the furnace system with no problem and I don't need to have extension cords running anywhere. Only problem with that is it's hard to tell when the power is back on. Turn off the breaker that feeds the shed, turn the main back on and see if your lights work. If so, shut off and unplug the generator then turn the breaker that feeds the shed back on. When Wilma hit in Florida I had a much bigger contractor's generator that had a 240 volt split phase output. I wired it into the power panel (illegally) on the load side of the main breaker and just made damn sure I didn't forget and turn the main back on. It worked fine except it burned so much gas I would have run out of my supply in a matter of a couple of days. Only used it for about an hour or less a day to run the well pump and the water heater so I could take showers. Other than that, I used the little Honda for the refrig, couple of lights, the TV and Direct TV receiver. My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) The one I had was bigger ... 14 KW, I think. |
Flurries
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Flurries
On 1/4/2018 11:42 PM, wrote:
On Thu, 4 Jan 2018 22:18:24 -0500, "Mr. Luddite" wrote: On 1/4/2018 5:46 PM, wrote: On Thu, 4 Jan 2018 15:23:28 -0500, "Mr. Luddite" wrote: I definitely agree that not everyone should do this. The best way is to have an automatic transfer box installed to code by a licensed electrician. That said, I've done this several times, including the house we had in Florida after Wilma. I have sufficient knowledge of what I am doing but even so, I stop, check and re-check before firing up the generator and throwing the breaker that it backfeeds through. It's illegal, but safe if you pay attention and know something about house wiring. Here's a little test that I've even tried on licensed electricians to see how knowledgeable they a Your house service is usually 240vac, split phase. Split phase means two "hot" leads, a neutral (used with both hot legs) and a ground (which really is tied to the neutral leg. Across the two "hot" leads you have 240 volts which is used for stoves, large AC units, etc. Between either hot lead and neutral you have 120 volts which is used for your outlets, lighting, refrig and small appliances. Your panel box is supposed to be wired to balance the loads as best as possible. So, here's the question. Let's say: Leg "A" of the 120 volt supply is drawing 40 amps. Leg "B" of the 120 volt supply is drawing 30 amps. How much current is flowing through the common neutral leg that is used for both legs? The answer is 10 amps. Many people assume it is the sum of both current draws or 70 amps in this example and it's amazing how many "electricians" don't know that. They don't realize that the two "hot" legs are 180 degrees out of phase, so the current in the neutral adds algebraically. That's why the neutral feed from the street to your power panel is the same size wire as the two hot leads. It will never carry more than what one hot leg is rated to draw. I can't imagine any real electrician does not know that. In fact with the right engineering, the neutral really only needs to be sized to the maximum unbalanced load. For example You are allowed to use 70% for ranges and dryers in dwelling calcs. OTOH on 3 phase, you may end up actually using a neutral of close to 200% of the ungrounded conductor load because of triplin harmonics. This became an issue with electronic ballasts and switcher power supplies. Only on three phase Wye. 3 phase Delta you don't have to worry about the neutral. I've never seen 3 phase service to a residential dwelling. Not saying it doesn't exist, I just have never seen or even heard of it. Both of the facilities I had for my company were 3 phase though, one 208v Wye, the other 480v Delta. I agree the harmonic problem is just on wye but that is the most common configuration, 208 or 480. I think the problem first showed up on 480/277 wye systems where they had a building full of 277v electronic ballasts. Then it started showing up in those 208 systems that were feeding 120v lines in cubicles through the internal wiring with a 5 wire feeder as PCs started replacing terminals with ferro power supplies and space heaters. Delta is always funny stuff, depending on where or even if you land the ground. Corner grounded is probably the easiest to confuse the novice. It will look just like single phase until you get your meter out. (2 pole breakers, white wires etc) Not familiar with that. The majority of the systems we built were designed to run on 480v, 3 phase. All the main breakers, fused disconnects, motor starters, etc. were three pole. Ground was run separately. We used a dedicated control transformer in each power cabinet to generate whatever the low voltage control wiring was ... 120v in the early days but later 24 volt. IIRC, the control transformer on the 120v systems was a 480v/240v step down with a center tap, providing a neutral. |
Flurries
On Friday, January 5, 2018 at 5:25:36 AM UTC-5, Mr. Luddite wrote:
On 1/5/2018 12:09 AM, wrote: On Thu, 4 Jan 2018 22:52:39 -0500, "Mr. Luddite" wrote: Don't know if it's still so but I remember in the old days you could remove the battery from a car once it was running and it continued to run just fine. They always warned you not to but I did it on my 69 Corvette and nothing bad happened. (dead battery, no cables and a borrowed battery to get it going) OTOH a new outboard (Yamaha or Mercury) will stop right away if you disconnect or even have an open cell in a battery. (over voltage) BTDT ... twice. I know that in many cases the battery in a boat acts as the voltage regulator. Yes, a large capacitor. It seems that most boat motors have fairly simple charging systems, unlike a car's alternator/voltage regulator. As far as taking the battery out of a running car, I agree that it was possible back in the day, but I sure wouldn't chance it in a modern car. Too many controllers (computers) spread around in today's cars. The battery still smooths out whatever is coming out of the alternator. You could brick your car. :) |
Flurries
On Fri, 05 Jan 2018 00:04:40 -0500, wrote:
On Thu, 4 Jan 2018 22:50:19 -0500, "Mr. Luddite" wrote: Harry's playing outside, four wheeling in his driveway in 4 inches of snow. Ny niece posted a picture on Facebook of a measured 6" a few miles south of Harry. He may have more than 4" of snow. I think Harry said he got 6", but the official record puts him between 2-4". http://www.weatherstreet.com/city_sn...snow-depth.htm We got about an inch. |
Flurries
Wrote in message:
On Thu, 4 Jan 2018 22:45:25 -0500, "Mr. Luddite" wrote: On 1/4/2018 7:43 PM, Alex wrote: Mr. Luddite wrote: On 1/4/2018 1:07 PM, John H wrote: On Thu, 4 Jan 2018 12:42:29 -0500, "Mr. Luddite" wrote: On 1/4/2018 12:20 PM, wrote: On Thu, 04 Jan 2018 08:54:03 -0500, John H wrote: On Wed, 3 Jan 2018 17:19:35 -0500, "Mr. Luddite" wrote: On 1/3/2018 2:28 PM, Its Me wrote: Light flurries now, the predictions range from a dusting to 1-2 inches. Worse the closer to the coast you get. My BIL at James Island (Charleston) sent a picture earlier of maybe 1/4 inch and still falling. Very unusual for them. It's out of here in a few hours and headed up the coast. Good luck! Damn. I was hoping it would dump a foot in Mt. Pleasant, just to shut my son up. Last I heard it is supposed to "explode" as it comes up the coast, becoming essentially a winter hurricane. "Bombogenesis" is the technical term, and the popular "bomb cyclone" is a shortened version of it, according to our weather folks. They do seem to just make up names for things these days. I think the classic was "Super Storm Sandy" to talk about something that was not even a hurricane, it was just "super" for people who were not used to tropical weather. It is far from unprecedented tho. There was a real Cat 3 there in the 30s. I have certainly seen that weather pattern in DC tho and this is not even the worst case. The snow would actually be more of a problem if the "eye" of that low was farther west so your wind was drawing wet gulf stream air up into the cold front north of you. That is what gives DC over a foot of snow a day and if it stalls, you "Knickerbocker" snow. Up here a Cat 1 hurricane in the summer might be preferable over what is going on right now. When you look at this storm on radar it is developing a very defined rotation as it is winding up and getting bigger. Snowfall rate here is 2-3 inches/hr and the temp is dropping like a rock since this morning. Pretty much a white-out out there. Major flooding in Justin's former town with 4 disabled cars with people trapped inside, one a woman with 2 kids. Water is over the wheel wells. Fire and National Guard are responding. My old stomping grounds in Scituate is really getting clobbered ... worst in over 30 years despite improvements in sea walls, etc. A TV reporter nut was standing on the porch of a house about 30 feet from the seawall and he was getting soaked with spray, along with dodging sea ice that is being thrown up onto the roofs of houses. So far we haven't had any power glitches here but I fully expect we'll lose it in the next hour or so. Wind where I am is gusting 55-60 mph. Best of luck in all that. I think I'd be getting out the extension cords and prioritizing my electricity requirements! Did that yesterday ... that's why I was firing up the Honda to test. I have a new plan. If power goes out I am going to shut off the main breaker and then backfeed the generator output through a 15 amp outlet that's in the shed. It's on the same branch of the split 240v house supply as the furnace and a couple of rooms. All my lighting is LED, so that's a tiny load. The generator will run those plus the furnace system with no problem and I don't need to have extension cords running anywhere. Only problem with that is it's hard to tell when the power is back on. Turn off the breaker that feeds the shed, turn the main back on and see if your lights work. If so, shut off and unplug the generator then turn the breaker that feeds the shed back on. When Wilma hit in Florida I had a much bigger contractor's generator that had a 240 volt split phase output. I wired it into the power panel (illegally) on the load side of the main breaker and just made damn sure I didn't forget and turn the main back on. It worked fine except it burned so much gas I would have run out of my supply in a matter of a couple of days. Only used it for about an hour or less a day to run the well pump and the water heater so I could take showers. Other than that, I used the little Honda for the refrig, couple of lights, the TV and Direct TV receiver. My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? What is involved in converting to propane? -- x ----Android NewsGroup Reader---- http://usenet.sinaapp.com/ |
Flurries
On Fri, 5 Jan 2018 08:32:51 -0500 (EST), justan wrote:
Wrote in message: On Thu, 4 Jan 2018 22:45:25 -0500, "Mr. Luddite" wrote: On 1/4/2018 7:43 PM, Alex wrote: Mr. Luddite wrote: On 1/4/2018 1:07 PM, John H wrote: On Thu, 4 Jan 2018 12:42:29 -0500, "Mr. Luddite" wrote: On 1/4/2018 12:20 PM, wrote: On Thu, 04 Jan 2018 08:54:03 -0500, John H wrote: On Wed, 3 Jan 2018 17:19:35 -0500, "Mr. Luddite" wrote: On 1/3/2018 2:28 PM, Its Me wrote: Light flurries now, the predictions range from a dusting to 1-2 inches. Worse the closer to the coast you get. My BIL at James Island (Charleston) sent a picture earlier of maybe 1/4 inch and still falling. Very unusual for them. It's out of here in a few hours and headed up the coast. Good luck! Damn. I was hoping it would dump a foot in Mt. Pleasant, just to shut my son up. Last I heard it is supposed to "explode" as it comes up the coast, becoming essentially a winter hurricane. "Bombogenesis" is the technical term, and the popular "bomb cyclone" is a shortened version of it, according to our weather folks. They do seem to just make up names for things these days. I think the classic was "Super Storm Sandy" to talk about something that was not even a hurricane, it was just "super" for people who were not used to tropical weather. It is far from unprecedented tho. There was a real Cat 3 there in the 30s. I have certainly seen that weather pattern in DC tho and this is not even the worst case. The snow would actually be more of a problem if the "eye" of that low was farther west so your wind was drawing wet gulf stream air up into the cold front north of you. That is what gives DC over a foot of snow a day and if it stalls, you "Knickerbocker" snow. Up here a Cat 1 hurricane in the summer might be preferable over what is going on right now. When you look at this storm on radar it is developing a very defined rotation as it is winding up and getting bigger. Snowfall rate here is 2-3 inches/hr and the temp is dropping like a rock since this morning. Pretty much a white-out out there. Major flooding in Justin's former town with 4 disabled cars with people trapped inside, one a woman with 2 kids. Water is over the wheel wells. Fire and National Guard are responding. My old stomping grounds in Scituate is really getting clobbered ... worst in over 30 years despite improvements in sea walls, etc. A TV reporter nut was standing on the porch of a house about 30 feet from the seawall and he was getting soaked with spray, along with dodging sea ice that is being thrown up onto the roofs of houses. So far we haven't had any power glitches here but I fully expect we'll lose it in the next hour or so. Wind where I am is gusting 55-60 mph. Best of luck in all that. I think I'd be getting out the extension cords and prioritizing my electricity requirements! Did that yesterday ... that's why I was firing up the Honda to test. I have a new plan. If power goes out I am going to shut off the main breaker and then backfeed the generator output through a 15 amp outlet that's in the shed. It's on the same branch of the split 240v house supply as the furnace and a couple of rooms. All my lighting is LED, so that's a tiny load. The generator will run those plus the furnace system with no problem and I don't need to have extension cords running anywhere. Only problem with that is it's hard to tell when the power is back on. Turn off the breaker that feeds the shed, turn the main back on and see if your lights work. If so, shut off and unplug the generator then turn the breaker that feeds the shed back on. When Wilma hit in Florida I had a much bigger contractor's generator that had a 240 volt split phase output. I wired it into the power panel (illegally) on the load side of the main breaker and just made damn sure I didn't forget and turn the main back on. It worked fine except it burned so much gas I would have run out of my supply in a matter of a couple of days. Only used it for about an hour or less a day to run the well pump and the water heater so I could take showers. Other than that, I used the little Honda for the refrig, couple of lights, the TV and Direct TV receiver. My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? What is involved in converting to propane? A place to start: http://www.uscarburetion.com/simple_explanation.htm |
Flurries
On 1/5/2018 8:32 AM, justan wrote:
Wrote in message: On Thu, 4 Jan 2018 22:45:25 -0500, "Mr. Luddite" wrote: On 1/4/2018 7:43 PM, Alex wrote: Mr. Luddite wrote: On 1/4/2018 1:07 PM, John H wrote: On Thu, 4 Jan 2018 12:42:29 -0500, "Mr. Luddite" wrote: On 1/4/2018 12:20 PM, wrote: On Thu, 04 Jan 2018 08:54:03 -0500, John H wrote: On Wed, 3 Jan 2018 17:19:35 -0500, "Mr. Luddite" wrote: On 1/3/2018 2:28 PM, Its Me wrote: Light flurries now, the predictions range from a dusting to 1-2 inches. Worse the closer to the coast you get. My BIL at James Island (Charleston) sent a picture earlier of maybe 1/4 inch and still falling. Very unusual for them. It's out of here in a few hours and headed up the coast. Good luck! Damn. I was hoping it would dump a foot in Mt. Pleasant, just to shut my son up. Last I heard it is supposed to "explode" as it comes up the coast, becoming essentially a winter hurricane. "Bombogenesis" is the technical term, and the popular "bomb cyclone" is a shortened version of it, according to our weather folks. They do seem to just make up names for things these days. I think the classic was "Super Storm Sandy" to talk about something that was not even a hurricane, it was just "super" for people who were not used to tropical weather. It is far from unprecedented tho. There was a real Cat 3 there in the 30s. I have certainly seen that weather pattern in DC tho and this is not even the worst case. The snow would actually be more of a problem if the "eye" of that low was farther west so your wind was drawing wet gulf stream air up into the cold front north of you. That is what gives DC over a foot of snow a day and if it stalls, you "Knickerbocker" snow. Up here a Cat 1 hurricane in the summer might be preferable over what is going on right now. When you look at this storm on radar it is developing a very defined rotation as it is winding up and getting bigger. Snowfall rate here is 2-3 inches/hr and the temp is dropping like a rock since this morning. Pretty much a white-out out there. Major flooding in Justin's former town with 4 disabled cars with people trapped inside, one a woman with 2 kids. Water is over the wheel wells. Fire and National Guard are responding. My old stomping grounds in Scituate is really getting clobbered ... worst in over 30 years despite improvements in sea walls, etc. A TV reporter nut was standing on the porch of a house about 30 feet from the seawall and he was getting soaked with spray, along with dodging sea ice that is being thrown up onto the roofs of houses. So far we haven't had any power glitches here but I fully expect we'll lose it in the next hour or so. Wind where I am is gusting 55-60 mph. Best of luck in all that. I think I'd be getting out the extension cords and prioritizing my electricity requirements! Did that yesterday ... that's why I was firing up the Honda to test. I have a new plan. If power goes out I am going to shut off the main breaker and then backfeed the generator output through a 15 amp outlet that's in the shed. It's on the same branch of the split 240v house supply as the furnace and a couple of rooms. All my lighting is LED, so that's a tiny load. The generator will run those plus the furnace system with no problem and I don't need to have extension cords running anywhere. Only problem with that is it's hard to tell when the power is back on. Turn off the breaker that feeds the shed, turn the main back on and see if your lights work. If so, shut off and unplug the generator then turn the breaker that feeds the shed back on. When Wilma hit in Florida I had a much bigger contractor's generator that had a 240 volt split phase output. I wired it into the power panel (illegally) on the load side of the main breaker and just made damn sure I didn't forget and turn the main back on. It worked fine except it burned so much gas I would have run out of my supply in a matter of a couple of days. Only used it for about an hour or less a day to run the well pump and the water heater so I could take showers. Other than that, I used the little Honda for the refrig, couple of lights, the TV and Direct TV receiver. My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? What is involved in converting to propane? I don't know what Greg meant by "8" on propane. Maybe point 8 gals/hr? Anyway, there are many conversion kits that can be found on Amazon and eBay to allow a generator to run on either gas or propane. I read a do it yourself method using an old carb but even the guy that did it warned that unlike the conversion kits, his doesn't automatically shut the propane flow off if the engine stalls. Probably dangerous. The kits I found ranged in price from under $20 to about $50. |
Flurries
wrote:
On Thu, 4 Jan 2018 22:50:19 -0500, "Mr. Luddite" wrote: Harry's playing outside, four wheeling in his driveway in 4 inches of snow. Ny niece posted a picture on Facebook of a measured 6" a few miles south of Harry. He may have more than 4" of snow. I measured 4”+ on two deck tables that aren’t subject to snow drifts. Main streets were plowed by the time I ventured out. Subdivision streets snowy and icey. Some empty shelves at supermarket, as is usual when a storm hits. Power hasn’t fluttered yet...propane tank was filled last week by supplier. -- Posted with my iPhone 8+. |
Flurries
On 1/4/18 10:50 PM, Mr. Luddite wrote:
On 1/4/2018 7:52 PM, Alex wrote: John H wrote: On Thu, 4 Jan 2018 15:23:28 -0500, "Mr. Luddite" wrote: On 1/4/2018 2:53 PM, John H wrote: On Thu, 4 Jan 2018 13:16:34 -0500, "Mr. Luddite" wrote: On 1/4/2018 1:07 PM, John H wrote: On Thu, 4 Jan 2018 12:42:29 -0500, "Mr. Luddite" wrote: On 1/4/2018 12:20 PM, wrote: On Thu, 04 Jan 2018 08:54:03 -0500, John H wrote: On Wed, 3 Jan 2018 17:19:35 -0500, "Mr. Luddite" wrote: On 1/3/2018 2:28 PM, Its Me wrote: Light flurries now, the predictions range from a dusting to 1-2 inches.* Worse the closer to the coast you get.* My BIL at James Island (Charleston) sent a picture earlier of maybe 1/4 inch and still falling.* Very unusual for them. It's out of here in a few hours and headed up the coast. Good luck! Damn.* I was hoping it would dump a foot in Mt. Pleasant, just to shut my son up. Last I heard it is supposed to "explode" as it comes up the coast, becoming essentially a winter hurricane. "Bombogenesis" is the technical term, and the popular "bomb cyclone" is a shortened version of it, according to our weather folks. They do seem to just make up names for things these days. I think the classic was "Super Storm Sandy" to talk about something that was not even a hurricane, it was just "super" for people who were not used to tropical weather. It is far from unprecedented tho. There was a real Cat 3 there in the 30s. I have certainly seen that weather pattern in DC tho and this is not even the worst case. The snow would actually be more of a problem if the "eye" of that low was farther west so your wind was drawing wet gulf stream air up into the cold front north of you. That is what gives DC over a foot of snow a day and if it stalls, you "Knickerbocker" snow. Up here a Cat 1 hurricane in the summer might be preferable over what is going on right now. When you look at this storm on radar it is developing a very defined rotation as it is winding up and getting bigger.* Snowfall rate here is 2-3 inches/hr and the temp is dropping like a rock since this morning.* Pretty much a white-out out there. Major flooding in Justin's former town with 4 disabled cars with people trapped inside, one a woman with 2 kids.* Water is over the wheel wells. *** Fire and National Guard are responding. My old stomping grounds in Scituate is really getting clobbered ... worst in over 30 years despite improvements in sea walls, etc. A TV reporter nut was standing on the porch of a house about 30 feet from the seawall and he was getting soaked with spray, along with dodging sea ice that is being thrown up onto the roofs of houses. So far we haven't had any power glitches here but I fully expect we'll lose it in the next hour or so. Wind where I am is gusting 55-60 mph. Best of luck in all that. I think I'd be getting out the extension cords and prioritizing my electricity requirements! Did that yesterday ... that's why I was firing up the Honda to test. I have a new plan.* If power goes out I am going to shut off the main breaker and then backfeed the generator output through a 15 amp outlet that's in the shed.* It's on the same branch of the split 240v house supply as the furnace and a couple of rooms.* All my lighting is LED, so that's a tiny load.* The generator will run those plus the furnace system with no problem and I don't need to have extension cords running anywhere. Well, you know more about electricity than I do. That's something I'd never try. Came across this while looking for info. Don't know if it'll help or you already have it down. http://www.tcscooters.com/backfeed.htm I like steps 1-3: If you are going to backfeed your home, you must be very carefully and follow the directions below. If you fail to follow them you can kill a line worker, kill yourself or blow up your generator. Again I'll say, get a licensed electrician. Step One, the most important step of all is to turn off the main breakers. Step two, turn off the main breakers. Step three, turn off the main breakers. Do you get the idea? Step four, remember to plug the generator end in last. If the generator is running and you are using two male ends the house end plug is live! I definitely agree that not everyone should do this.* The best way is to have an automatic transfer box installed to code by a licensed electrician. That said, I've done this several times, including the house we had in Florida after Wilma.* I have sufficient knowledge of what I am doing but even so, I stop, check and re-check before firing up the generator and throwing the breaker that it backfeeds through. It's illegal, but safe if you pay attention and know something about house wiring. Here's a little test that I've even tried on licensed electricians to see how knowledgeable they a Your house service is usually 240vac, split phase.* Split phase means two "hot" leads, a neutral (used with both hot legs) and a ground (which really is tied to the neutral leg.* Across the two "hot" leads you have 240 volts which is used for stoves, large AC units, etc.* Between either hot lead and neutral you have 120 volts which is used for your outlets, lighting, refrig and small appliances.* Your panel box is supposed to be wired to balance the loads as best as possible.* So, here's the question.* Let's say: Leg "A" of the 120 volt supply is drawing* 40 amps. Leg "B" of the 120 volt supply is drawing* 30 amps. How much current is flowing through the common neutral leg that is used for both legs? The answer is 10 amps. Many people assume it is the sum of both current draws or 70 amps in this example and it's amazing how many "electricians" don't know that. They don't realize that the two "hot" legs are 180 degrees out of phase, so the current in the neutral adds algebraically. That's why the neutral feed from the street to your power panel is the same size wire as the two hot leads.* It will never carry more than what one hot leg is rated to draw. I would have guessed 35. But, that's just proof of how little I know about electricity, off the top of my head. Harry would have got it right. Maybe not.* It's probably not an easy Google search and his union buddies wouldn't know the answer. Harry's playing outside, four wheeling in his driveway in 4 inches of snow. I don't read posts from Herring unless a bit of them is quoted in someone else's post. Whatever the question was, if I had the information Herring needed, I'd go make a sandwich instead. |
Flurries
On Fri, 5 Jan 2018 05:34:25 -0500, "Mr. Luddite"
wrote: I agree the harmonic problem is just on wye but that is the most common configuration, 208 or 480. I think the problem first showed up on 480/277 wye systems where they had a building full of 277v electronic ballasts. Then it started showing up in those 208 systems that were feeding 120v lines in cubicles through the internal wiring with a 5 wire feeder as PCs started replacing terminals with ferro power supplies and space heaters. Delta is always funny stuff, depending on where or even if you land the ground. Corner grounded is probably the easiest to confuse the novice. It will look just like single phase until you get your meter out. (2 pole breakers, white wires etc) Not familiar with that. The majority of the systems we built were designed to run on 480v, 3 phase. All the main breakers, fused disconnects, motor starters, etc. were three pole. Ground was run separately. We used a dedicated control transformer in each power cabinet to generate whatever the low voltage control wiring was ... 120v in the early days but later 24 volt. IIRC, the control transformer on the 120v systems was a 480v/240v step down with a center tap, providing a neutral. Did you ground your 480 delta at all? If so where did the ground land? I understand your control circuit voltage can be 120 if you want. That is just a class 1 control circuit. Most people are familiar with class 2 but they are both controlled by the same article in the NEC. Class 1 just looks like regular line voltage circuits because it is not voltage or current limited like class 2 and 3. The center tapped 240 delta is commonly called "red leg" or "wild leg"because the corner between the center tapped windings will be 208v to ground. "Red" is a misnomer tho because the NEC requires the wire to be orange. That is very common in places where they want discount 3 phase and have a significant amount of single phase loads like those small industrial bays. The PoCo can do it with 2 transformers, generally the wild leg will be on a much smaller one. One "winding" is actually open. hence another name, "Delta Veep". http://gfretwell.com/electrical/red%...ansformers.jpg 99.99% of the time, if you see 3 transformers on the pole, it will be wye. but I have seen one place in Key West where they had red leg delta with 3 transformers. The only tip off was one was bigger than the other two and it was confirmed by analysing the wiring. http://gfretwell.com/electrical/Tran...%20_breath.jpg Yeah my wife thinks I am crazy too, taking pictures of transformers. |
Flurries
On Fri, 05 Jan 2018 08:11:57 -0500, John H
wrote: On Fri, 05 Jan 2018 00:04:40 -0500, wrote: On Thu, 4 Jan 2018 22:50:19 -0500, "Mr. Luddite" wrote: Harry's playing outside, four wheeling in his driveway in 4 inches of snow. Ny niece posted a picture on Facebook of a measured 6" a few miles south of Harry. He may have more than 4" of snow. I think Harry said he got 6", but the official record puts him between 2-4". http://www.weatherstreet.com/city_sn...snow-depth.htm We got about an inch. Just going on the picture my niece posted from her marina in Ridge. (Ruler stuck in the snow) |
Flurries
On Fri, 5 Jan 2018 08:32:51 -0500 (EST), justan wrote:
Wrote in message: My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? gallons of propane an hour What is involved in converting to propane? You remove the carb, install longer studs, slip the propane venturi over the studs and reinstall the carb. Then you mount the regulator, hook up the hoses and you are ready to rock. The whole thing takes less than an hour the first time and I bet I can do it in 15 minutes now. They give you the initial setting on the control block for nat gas or propane and you dial it in from there once you get it running. I may be able to improve the fuel consumption a little but I would rather be too rich than too lean. I have it pretty close tho. |
Flurries
On Fri, 05 Jan 2018 08:47:56 -0500, John H
wrote: On Fri, 5 Jan 2018 08:32:51 -0500 (EST), justan wrote: Wrote in message: My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? What is involved in converting to propane? A place to start: http://www.uscarburetion.com/simple_explanation.htm That is the place where I got mine. They are great on the phone if you need help. I was OK but it just sounded too simple and I wanted to be sure I did everything right before I fired it up. |
Flurries
On 1/5/2018 11:37 AM, wrote:
On Fri, 5 Jan 2018 05:34:25 -0500, "Mr. Luddite" wrote: I agree the harmonic problem is just on wye but that is the most common configuration, 208 or 480. I think the problem first showed up on 480/277 wye systems where they had a building full of 277v electronic ballasts. Then it started showing up in those 208 systems that were feeding 120v lines in cubicles through the internal wiring with a 5 wire feeder as PCs started replacing terminals with ferro power supplies and space heaters. Delta is always funny stuff, depending on where or even if you land the ground. Corner grounded is probably the easiest to confuse the novice. It will look just like single phase until you get your meter out. (2 pole breakers, white wires etc) Not familiar with that. The majority of the systems we built were designed to run on 480v, 3 phase. All the main breakers, fused disconnects, motor starters, etc. were three pole. Ground was run separately. We used a dedicated control transformer in each power cabinet to generate whatever the low voltage control wiring was ... 120v in the early days but later 24 volt. IIRC, the control transformer on the 120v systems was a 480v/240v step down with a center tap, providing a neutral. Did you ground your 480 delta at all? If so where did the ground land? I understand your control circuit voltage can be 120 if you want. That is just a class 1 control circuit. Most people are familiar with class 2 but they are both controlled by the same article in the NEC. Class 1 just looks like regular line voltage circuits because it is not voltage or current limited like class 2 and 3. The center tapped 240 delta is commonly called "red leg" or "wild leg"because the corner between the center tapped windings will be 208v to ground. "Red" is a misnomer tho because the NEC requires the wire to be orange. That is very common in places where they want discount 3 phase and have a significant amount of single phase loads like those small industrial bays. The PoCo can do it with 2 transformers, generally the wild leg will be on a much smaller one. One "winding" is actually open. hence another name, "Delta Veep". http://gfretwell.com/electrical/red%...ansformers.jpg 99.99% of the time, if you see 3 transformers on the pole, it will be wye. but I have seen one place in Key West where they had red leg delta with 3 transformers. The only tip off was one was bigger than the other two and it was confirmed by analysing the wiring. http://gfretwell.com/electrical/Tran...%20_breath.jpg Yeah my wife thinks I am crazy too, taking pictures of transformers. Ground for the 480 Delta system service was run separately back to the physical (metallic) ground at the panel, usually via a 6 awg wire. Ground was not taken from any of the legs of the 3 phase Delta the way you have described. Many of the systems we built also had a RFI ground consisting of wide, copper flashing to two, 8' copper rods driven through the floor and into the ground. The rods were about 10-15 feet apart and we tried to get close to 1 ohm resistance between them. This often required a copper sulfate solution to be poured into the rod holes. The reason for the exotic grounding had nothing to do with safety. Many of the systems utilized a RF transmitter running at 13 Mhz. The load for the RF transmitter was a plasma (ionized partial pressure gas) generated within the vacuum chamber. We had specially designed "matchboxes" that allowed load impedance matching of the 50 ohm transmitter output to the very low impedance of the plasma. Other systems used an electron beam operating at 10,000 volts. A stream of electrons are emitted from a filament and focused magnetically onto various metals or dielectrics that were vaporized by the beam and deposited on optics in very carefully controlled thicknesses. Anyway, there were often some arcs and sparks within the chamber with either of these deposition methods that would raise hell with some of the very sensitive measurement instruments. The elaborate grounding, using a wide conductor (flashing) is much better at RF and EMI quenching of the arcs. A simple, round ground wire has too much inductive reactance. It's only purpose on these systems was to serve as a safety ground. Sometimes we'd have to chase our tail for a while however because the use of both grounding systems sometimes generated a ground loop which only magnified the RFI problem. |
Flurries
On Friday, January 5, 2018 at 11:49:34 AM UTC-5, wrote:
On Fri, 5 Jan 2018 08:32:51 -0500 (EST), justan wrote: Wrote in message: My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? gallons of propane an hour What is involved in converting to propane? You remove the carb, install longer studs, slip the propane venturi over the studs and reinstall the carb. Then you mount the regulator, hook up the hoses and you are ready to rock. The whole thing takes less than an hour the first time and I bet I can do it in 15 minutes now. They give you the initial setting on the control block for nat gas or propane and you dial it in from there once you get it running. I may be able to improve the fuel consumption a little but I would rather be too rich than too lean. I have it pretty close tho. What are the advantages of running on propane other than the possibility of having a large, buried propane tank as your source? I have a 330 gallon buried tank, but at 8 gallons an hour and an ~80% fill, that's less than 2 days run time. That equates to about 20 gallons of gas, if my preacher math is correct. |
Flurries
On Friday, January 5, 2018 at 12:28:57 PM UTC-5, Mr. Luddite wrote:
On 1/5/2018 11:37 AM, wrote: On Fri, 5 Jan 2018 05:34:25 -0500, "Mr. Luddite" wrote: I agree the harmonic problem is just on wye but that is the most common configuration, 208 or 480. I think the problem first showed up on 480/277 wye systems where they had a building full of 277v electronic ballasts. Then it started showing up in those 208 systems that were feeding 120v lines in cubicles through the internal wiring with a 5 wire feeder as PCs started replacing terminals with ferro power supplies and space heaters. Delta is always funny stuff, depending on where or even if you land the ground. Corner grounded is probably the easiest to confuse the novice. It will look just like single phase until you get your meter out. (2 pole breakers, white wires etc) Not familiar with that. The majority of the systems we built were designed to run on 480v, 3 phase. All the main breakers, fused disconnects, motor starters, etc. were three pole. Ground was run separately. We used a dedicated control transformer in each power cabinet to generate whatever the low voltage control wiring was ... 120v in the early days but later 24 volt. IIRC, the control transformer on the 120v systems was a 480v/240v step down with a center tap, providing a neutral. Did you ground your 480 delta at all? If so where did the ground land? I understand your control circuit voltage can be 120 if you want. That is just a class 1 control circuit. Most people are familiar with class 2 but they are both controlled by the same article in the NEC. Class 1 just looks like regular line voltage circuits because it is not voltage or current limited like class 2 and 3. The center tapped 240 delta is commonly called "red leg" or "wild leg"because the corner between the center tapped windings will be 208v to ground. "Red" is a misnomer tho because the NEC requires the wire to be orange. That is very common in places where they want discount 3 phase and have a significant amount of single phase loads like those small industrial bays. The PoCo can do it with 2 transformers, generally the wild leg will be on a much smaller one. One "winding" is actually open. hence another name, "Delta Veep". http://gfretwell.com/electrical/red%...ansformers.jpg 99.99% of the time, if you see 3 transformers on the pole, it will be wye. but I have seen one place in Key West where they had red leg delta with 3 transformers. The only tip off was one was bigger than the other two and it was confirmed by analysing the wiring. http://gfretwell.com/electrical/Tran...%20_breath.jpg Yeah my wife thinks I am crazy too, taking pictures of transformers. Ground for the 480 Delta system service was run separately back to the physical (metallic) ground at the panel, usually via a 6 awg wire. Ground was not taken from any of the legs of the 3 phase Delta the way you have described. Many of the systems we built also had a RFI ground consisting of wide, copper flashing to two, 8' copper rods driven through the floor and into the ground. The rods were about 10-15 feet apart and we tried to get close to 1 ohm resistance between them. This often required a copper sulfate solution to be poured into the rod holes. The reason for the exotic grounding had nothing to do with safety. Many of the systems utilized a RF transmitter running at 13 Mhz. The load for the RF transmitter was a plasma (ionized partial pressure gas) generated within the vacuum chamber. We had specially designed "matchboxes" that allowed load impedance matching of the 50 ohm transmitter output to the very low impedance of the plasma. Other systems used an electron beam operating at 10,000 volts. A stream of electrons are emitted from a filament and focused magnetically onto various metals or dielectrics that were vaporized by the beam and deposited on optics in very carefully controlled thicknesses.. Anyway, there were often some arcs and sparks within the chamber with either of these deposition methods that would raise hell with some of the very sensitive measurement instruments. The elaborate grounding, using a wide conductor (flashing) is much better at RF and EMI quenching of the arcs. A simple, round ground wire has too much inductive reactance. It's only purpose on these systems was to serve as a safety ground. Sometimes we'd have to chase our tail for a while however because the use of both grounding systems sometimes generated a ground loop which only magnified the RFI problem. I'm familiar with the type of grounding system you're describing. I've working in many equipment rooms over the years with all types of RF and communications equipment, and they almost always have the copper flashing and bars for grounding the equipment. The craziest thing I ever saw was a fire lookout tower on top of an 8k foot mountain in northern CA. It was a 3 story structure with something that looked like a chain-link fence around the roof, with huge cables coming down all four corners, then across the stone mountaintop with rods driven into the stone every so often for maybe 100 feet. This was for lightning protection. It's not the lightning that kills the equipment, it's the difference in potential that kills equipment. So the idea is to get the building, equipment (and ground system) inside the building, and the mountaintop to all rise up to the lightning potential together, then drain back down together. They said it got struck several times every summer with rare losses. Probably pretty exciting for the person inside! It had one other interesting feature... a scuttle hole on the roof with a ladder partially down one side of the building. That was for winter access when they used snow cats to get up there. I was there in the summer. :) |
Flurries
On Fri, 5 Jan 2018 12:28:51 -0500, "Mr. Luddite"
wrote: On 1/5/2018 11:37 AM, wrote: On Fri, 5 Jan 2018 05:34:25 -0500, "Mr. Luddite" wrote: I agree the harmonic problem is just on wye but that is the most common configuration, 208 or 480. I think the problem first showed up on 480/277 wye systems where they had a building full of 277v electronic ballasts. Then it started showing up in those 208 systems that were feeding 120v lines in cubicles through the internal wiring with a 5 wire feeder as PCs started replacing terminals with ferro power supplies and space heaters. Delta is always funny stuff, depending on where or even if you land the ground. Corner grounded is probably the easiest to confuse the novice. It will look just like single phase until you get your meter out. (2 pole breakers, white wires etc) Not familiar with that. The majority of the systems we built were designed to run on 480v, 3 phase. All the main breakers, fused disconnects, motor starters, etc. were three pole. Ground was run separately. We used a dedicated control transformer in each power cabinet to generate whatever the low voltage control wiring was ... 120v in the early days but later 24 volt. IIRC, the control transformer on the 120v systems was a 480v/240v step down with a center tap, providing a neutral. Did you ground your 480 delta at all? If so where did the ground land? I understand your control circuit voltage can be 120 if you want. That is just a class 1 control circuit. Most people are familiar with class 2 but they are both controlled by the same article in the NEC. Class 1 just looks like regular line voltage circuits because it is not voltage or current limited like class 2 and 3. The center tapped 240 delta is commonly called "red leg" or "wild leg"because the corner between the center tapped windings will be 208v to ground. "Red" is a misnomer tho because the NEC requires the wire to be orange. That is very common in places where they want discount 3 phase and have a significant amount of single phase loads like those small industrial bays. The PoCo can do it with 2 transformers, generally the wild leg will be on a much smaller one. One "winding" is actually open. hence another name, "Delta Veep". http://gfretwell.com/electrical/red%...ansformers.jpg 99.99% of the time, if you see 3 transformers on the pole, it will be wye. but I have seen one place in Key West where they had red leg delta with 3 transformers. The only tip off was one was bigger than the other two and it was confirmed by analysing the wiring. http://gfretwell.com/electrical/Tran...%20_breath.jpg Yeah my wife thinks I am crazy too, taking pictures of transformers. Ground for the 480 Delta system service was run separately back to the physical (metallic) ground at the panel, usually via a 6 awg wire. Ground was not taken from any of the legs of the 3 phase Delta the way you have described. Many of the systems we built also had a RFI ground consisting of wide, copper flashing to two, 8' copper rods driven through the floor and into the ground. The rods were about 10-15 feet apart and we tried to get close to 1 ohm resistance between them. This often required a copper sulfate solution to be poured into the rod holes. The reason for the exotic grounding had nothing to do with safety. Many of the systems utilized a RF transmitter running at 13 Mhz. The load for the RF transmitter was a plasma (ionized partial pressure gas) generated within the vacuum chamber. We had specially designed "matchboxes" that allowed load impedance matching of the 50 ohm transmitter output to the very low impedance of the plasma. Other systems used an electron beam operating at 10,000 volts. A stream of electrons are emitted from a filament and focused magnetically onto various metals or dielectrics that were vaporized by the beam and deposited on optics in very carefully controlled thicknesses. Anyway, there were often some arcs and sparks within the chamber with either of these deposition methods that would raise hell with some of the very sensitive measurement instruments. The elaborate grounding, using a wide conductor (flashing) is much better at RF and EMI quenching of the arcs. A simple, round ground wire has too much inductive reactance. It's only purpose on these systems was to serve as a safety ground. Sometimes we'd have to chase our tail for a while however because the use of both grounding systems sometimes generated a ground loop which only magnified the RFI problem. So you were running ungrounded delta. That is fairly rare and usually only for systems that are very intolerant of faults, like a glass plant where a power failure makes the whole place pretty much trash. I assume you had ground fault indicators since the first ground fault is "free". I have never actually seen ungrounded delta here. The other option is impedance grounding that grounds the system via a resistor, just to stabilize the voltage, not to provide any fault protection. You are right that there is no exception that allows the non current carrying parts of the system to be ungrounded. They are really trying to change that terminology to "bonded" to avoid confusion with the "grounded conductor" that we normally call the neutral and the "grounding electrode" that is your physical connection with earth. Article 250 may be the most misunderstood article in the whole NEC, hence the one I spent the most time studying. They are trying to redefine some of the terms to make it easier to understand because "ground" is such an all encompassing word that it misses the intent about half the time and when you actually start testing, it isn't even the same voltage from one place to another when you actually test with stakes in the dirt. |
Flurries
On Fri, 5 Jan 2018 09:29:32 -0800 (PST), Its Me
wrote: On Friday, January 5, 2018 at 11:49:34 AM UTC-5, wrote: On Fri, 5 Jan 2018 08:32:51 -0500 (EST), justan wrote: Wrote in message: My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? gallons of propane an hour What is involved in converting to propane? You remove the carb, install longer studs, slip the propane venturi over the studs and reinstall the carb. Then you mount the regulator, hook up the hoses and you are ready to rock. The whole thing takes less than an hour the first time and I bet I can do it in 15 minutes now. They give you the initial setting on the control block for nat gas or propane and you dial it in from there once you get it running. I may be able to improve the fuel consumption a little but I would rather be too rich than too lean. I have it pretty close tho. What are the advantages of running on propane other than the possibility of having a large, buried propane tank as your source? I have a 330 gallon buried tank, but at 8 gallons an hour and an ~80% fill, that's less than 2 days run time. That equates to about 20 gallons of gas, if my preacher math is correct. I may have slipped a decimal point on you. The gas to propane ratio is ~5:8. I had all of that stuff written down but I lost the paper. I just remembered the 8, not that it was 0.8 5 gallons of gas ran me about 10 hours and that took ~8 gallons of propane ... based on the gauge. I still have not refilled the tank so I do not have the actual number and since I don't have my log, I doubt I ever will know exactly what my burn rate was. The next time I feel like working on my generator, I have an hour meter I will be installing but it is hard to think about that stuff when the power is on ;-) |
Flurries
On Fri, 5 Jan 2018 09:45:14 -0800 (PST), Its Me
wrote: I'm familiar with the type of grounding system you're describing. I've working in many equipment rooms over the years with all types of RF and communications equipment, and they almost always have the copper flashing and bars for grounding the equipment. The craziest thing I ever saw was a fire lookout tower on top of an 8k foot mountain in northern CA. It was a 3 story structure with something that looked like a chain-link fence around the roof, with huge cables coming down all four corners, then across the stone mountaintop with rods driven into the stone every so often for maybe 100 feet. This was for lightning protection. It's not the lightning that kills the equipment, it's the difference in potential that kills equipment. So the idea is to get the building, equipment (and ground system) inside the building, and the mountaintop to all rise up to the lightning potential together, then drain back down together. They said it got struck several times every summer with rare losses. Probably pretty exciting for the person inside! It had one other interesting feature... a scuttle hole on the roof with a ladder partially down one side of the building. That was for winter access when they used snow cats to get up there. I was there in the summer. :) They do a similar thing for radio towers and strangely, toll booths. Around here "Ground" is just a vague reference to zero volts so they really need a lot of electrode to get the job done. In both the radio towers and the toll complex they used a buried ground ring of braided #2 copper around the whole complex with 40' rods cad welded every 50 feet or so all the way around the ring. At the toll complex (MM99 I-75) it looked like the 4th of july when they were firing all of those cad welds. My weather station on the garage has a 3/8" lightning rod over it with a #2 copper going to 3 rods that is also connected to the GES for the service and everything else. It has been hit several times and not hurt anything here after I hung some ferrites on the data lead coming down. Before that I did take put a serial port on a laptop. |
Flurries
On Friday, January 5, 2018 at 2:15:45 PM UTC-5, wrote:
On Fri, 5 Jan 2018 09:29:32 -0800 (PST), Its Me wrote: On Friday, January 5, 2018 at 11:49:34 AM UTC-5, wrote: On Fri, 5 Jan 2018 08:32:51 -0500 (EST), justan wrote: Wrote in message: My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? gallons of propane an hour What is involved in converting to propane? You remove the carb, install longer studs, slip the propane venturi over the studs and reinstall the carb. Then you mount the regulator, hook up the hoses and you are ready to rock. The whole thing takes less than an hour the first time and I bet I can do it in 15 minutes now. They give you the initial setting on the control block for nat gas or propane and you dial it in from there once you get it running. I may be able to improve the fuel consumption a little but I would rather be too rich than too lean. I have it pretty close tho. What are the advantages of running on propane other than the possibility of having a large, buried propane tank as your source? I have a 330 gallon buried tank, but at 8 gallons an hour and an ~80% fill, that's less than 2 days run time. That equates to about 20 gallons of gas, if my preacher math is correct. I may have slipped a decimal point on you. The gas to propane ratio is ~5:8. I had all of that stuff written down but I lost the paper. I just remembered the 8, not that it was 0.8 5 gallons of gas ran me about 10 hours and that took ~8 gallons of propane ... based on the gauge. I still have not refilled the tank so I do not have the actual number and since I don't have my log, I doubt I ever will know exactly what my burn rate was. The next time I feel like working on my generator, I have an hour meter I will be installing but it is hard to think about that stuff when the power is on ;-) Ah, gotcha. That makes much more sense. The propane is still more costly, but the ease of long term storage of large amounts far outweigh the costs. I keep saying that I'm going to buy a generator, but in the last ten years we've probably lost power for a total of 4 hours or so. Hard to justify it, until you need it. |
Flurries
On 1/5/18 11:49 AM, wrote:
On Fri, 5 Jan 2018 08:32:51 -0500 (EST), justan wrote: Wrote in message: My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? gallons of propane an hour What is involved in converting to propane? You remove the carb, install longer studs, slip the propane venturi over the studs and reinstall the carb. Then you mount the regulator, hook up the hoses and you are ready to rock. The whole thing takes less than an hour the first time and I bet I can do it in 15 minutes now. They give you the initial setting on the control block for nat gas or propane and you dial it in from there once you get it running. I may be able to improve the fuel consumption a little but I would rather be too rich than too lean. I have it pretty close tho. I haven't been once disappointed that we bite the bullet and bought our propane genny for the house. We have a propane/electric hot air heat pump for the main level, and the genny will run that and almost everything else in the house turned on at the same time. It'll also run the a/c on the unit in the summer plus all the important other stuff. I think I recall that it uses 1.5 to 2. gallons of propane an hour running at at least a half load. |
Flurries
On Fri, 05 Jan 2018 11:37:20 -0500, wrote:
On Fri, 5 Jan 2018 05:34:25 -0500, "Mr. Luddite" wrote: I agree the harmonic problem is just on wye but that is the most common configuration, 208 or 480. I think the problem first showed up on 480/277 wye systems where they had a building full of 277v electronic ballasts. Then it started showing up in those 208 systems that were feeding 120v lines in cubicles through the internal wiring with a 5 wire feeder as PCs started replacing terminals with ferro power supplies and space heaters. Delta is always funny stuff, depending on where or even if you land the ground. Corner grounded is probably the easiest to confuse the novice. It will look just like single phase until you get your meter out. (2 pole breakers, white wires etc) Not familiar with that. The majority of the systems we built were designed to run on 480v, 3 phase. All the main breakers, fused disconnects, motor starters, etc. were three pole. Ground was run separately. We used a dedicated control transformer in each power cabinet to generate whatever the low voltage control wiring was ... 120v in the early days but later 24 volt. IIRC, the control transformer on the 120v systems was a 480v/240v step down with a center tap, providing a neutral. Did you ground your 480 delta at all? If so where did the ground land? I understand your control circuit voltage can be 120 if you want. That is just a class 1 control circuit. Most people are familiar with class 2 but they are both controlled by the same article in the NEC. Class 1 just looks like regular line voltage circuits because it is not voltage or current limited like class 2 and 3. The center tapped 240 delta is commonly called "red leg" or "wild leg"because the corner between the center tapped windings will be 208v to ground. "Red" is a misnomer tho because the NEC requires the wire to be orange. That is very common in places where they want discount 3 phase and have a significant amount of single phase loads like those small industrial bays. The PoCo can do it with 2 transformers, generally the wild leg will be on a much smaller one. One "winding" is actually open. hence another name, "Delta Veep". http://gfretwell.com/electrical/red%...ansformers.jpg 99.99% of the time, if you see 3 transformers on the pole, it will be wye. but I have seen one place in Key West where they had red leg delta with 3 transformers. The only tip off was one was bigger than the other two and it was confirmed by analysing the wiring. http://gfretwell.com/electrical/Tran...%20_breath.jpg Yeah my wife thinks I am crazy too, taking pictures of transformers. === Remind her that it could be worse, like taking pictures of half n'ked babes at the beach. :-) --- This email has been checked for viruses by AVG. http://www.avg.com |
Flurries
On Fri, 5 Jan 2018 11:47:02 -0800 (PST), Its Me
wrote: On Friday, January 5, 2018 at 2:15:45 PM UTC-5, wrote: On Fri, 5 Jan 2018 09:29:32 -0800 (PST), Its Me wrote: On Friday, January 5, 2018 at 11:49:34 AM UTC-5, wrote: On Fri, 5 Jan 2018 08:32:51 -0500 (EST), justan wrote: Wrote in message: My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? gallons of propane an hour What is involved in converting to propane? You remove the carb, install longer studs, slip the propane venturi over the studs and reinstall the carb. Then you mount the regulator, hook up the hoses and you are ready to rock. The whole thing takes less than an hour the first time and I bet I can do it in 15 minutes now. They give you the initial setting on the control block for nat gas or propane and you dial it in from there once you get it running. I may be able to improve the fuel consumption a little but I would rather be too rich than too lean. I have it pretty close tho. What are the advantages of running on propane other than the possibility of having a large, buried propane tank as your source? I have a 330 gallon buried tank, but at 8 gallons an hour and an ~80% fill, that's less than 2 days run time. That equates to about 20 gallons of gas, if my preacher math is correct. I may have slipped a decimal point on you. The gas to propane ratio is ~5:8. I had all of that stuff written down but I lost the paper. I just remembered the 8, not that it was 0.8 5 gallons of gas ran me about 10 hours and that took ~8 gallons of propane ... based on the gauge. I still have not refilled the tank so I do not have the actual number and since I don't have my log, I doubt I ever will know exactly what my burn rate was. The next time I feel like working on my generator, I have an hour meter I will be installing but it is hard to think about that stuff when the power is on ;-) Ah, gotcha. That makes much more sense. The propane is still more costly, but the ease of long term storage of large amounts far outweigh the costs. I keep saying that I'm going to buy a generator, but in the last ten years we've probably lost power for a total of 4 hours or so. Hard to justify it, until you need it. === Yes, but once you go into a multi day power outage a generator is a really nice thing to have. We're fortunate to have a good sized diesel generator on the boat with 500+ gallons of fuel typically. With a little red neck engineering we can power the entire house including the central air, stove and hot water heater. --- This email has been checked for viruses by AVG. http://www.avg.com |
Flurries
On Fri, 5 Jan 2018 11:47:02 -0800 (PST), Its Me
wrote: On Friday, January 5, 2018 at 2:15:45 PM UTC-5, wrote: On Fri, 5 Jan 2018 09:29:32 -0800 (PST), Its Me wrote: On Friday, January 5, 2018 at 11:49:34 AM UTC-5, wrote: On Fri, 5 Jan 2018 08:32:51 -0500 (EST), justan wrote: Wrote in message: My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? gallons of propane an hour What is involved in converting to propane? You remove the carb, install longer studs, slip the propane venturi over the studs and reinstall the carb. Then you mount the regulator, hook up the hoses and you are ready to rock. The whole thing takes less than an hour the first time and I bet I can do it in 15 minutes now. They give you the initial setting on the control block for nat gas or propane and you dial it in from there once you get it running. I may be able to improve the fuel consumption a little but I would rather be too rich than too lean. I have it pretty close tho. What are the advantages of running on propane other than the possibility of having a large, buried propane tank as your source? I have a 330 gallon buried tank, but at 8 gallons an hour and an ~80% fill, that's less than 2 days run time. That equates to about 20 gallons of gas, if my preacher math is correct. I may have slipped a decimal point on you. The gas to propane ratio is ~5:8. I had all of that stuff written down but I lost the paper. I just remembered the 8, not that it was 0.8 5 gallons of gas ran me about 10 hours and that took ~8 gallons of propane ... based on the gauge. I still have not refilled the tank so I do not have the actual number and since I don't have my log, I doubt I ever will know exactly what my burn rate was. The next time I feel like working on my generator, I have an hour meter I will be installing but it is hard to think about that stuff when the power is on ;-) Ah, gotcha. That makes much more sense. The propane is still more costly, but the ease of long term storage of large amounts far outweigh the costs. I keep saying that I'm going to buy a generator, but in the last ten years we've probably lost power for a total of 4 hours or so. Hard to justify it, until you need it. I didn't plan to myself but a guy made me an offer I couldn't refuse. 5.5KW Briggs NIB $300 |
Flurries
|
Flurries
On 1/5/2018 2:06 PM, wrote:
On Fri, 5 Jan 2018 12:28:51 -0500, "Mr. Luddite" wrote: On 1/5/2018 11:37 AM, wrote: On Fri, 5 Jan 2018 05:34:25 -0500, "Mr. Luddite" wrote: I agree the harmonic problem is just on wye but that is the most common configuration, 208 or 480. I think the problem first showed up on 480/277 wye systems where they had a building full of 277v electronic ballasts. Then it started showing up in those 208 systems that were feeding 120v lines in cubicles through the internal wiring with a 5 wire feeder as PCs started replacing terminals with ferro power supplies and space heaters. Delta is always funny stuff, depending on where or even if you land the ground. Corner grounded is probably the easiest to confuse the novice. It will look just like single phase until you get your meter out. (2 pole breakers, white wires etc) Not familiar with that. The majority of the systems we built were designed to run on 480v, 3 phase. All the main breakers, fused disconnects, motor starters, etc. were three pole. Ground was run separately. We used a dedicated control transformer in each power cabinet to generate whatever the low voltage control wiring was ... 120v in the early days but later 24 volt. IIRC, the control transformer on the 120v systems was a 480v/240v step down with a center tap, providing a neutral. Did you ground your 480 delta at all? If so where did the ground land? I understand your control circuit voltage can be 120 if you want. That is just a class 1 control circuit. Most people are familiar with class 2 but they are both controlled by the same article in the NEC. Class 1 just looks like regular line voltage circuits because it is not voltage or current limited like class 2 and 3. The center tapped 240 delta is commonly called "red leg" or "wild leg"because the corner between the center tapped windings will be 208v to ground. "Red" is a misnomer tho because the NEC requires the wire to be orange. That is very common in places where they want discount 3 phase and have a significant amount of single phase loads like those small industrial bays. The PoCo can do it with 2 transformers, generally the wild leg will be on a much smaller one. One "winding" is actually open. hence another name, "Delta Veep". http://gfretwell.com/electrical/red%...ansformers.jpg 99.99% of the time, if you see 3 transformers on the pole, it will be wye. but I have seen one place in Key West where they had red leg delta with 3 transformers. The only tip off was one was bigger than the other two and it was confirmed by analysing the wiring. http://gfretwell.com/electrical/Tran...%20_breath.jpg Yeah my wife thinks I am crazy too, taking pictures of transformers. Ground for the 480 Delta system service was run separately back to the physical (metallic) ground at the panel, usually via a 6 awg wire. Ground was not taken from any of the legs of the 3 phase Delta the way you have described. Many of the systems we built also had a RFI ground consisting of wide, copper flashing to two, 8' copper rods driven through the floor and into the ground. The rods were about 10-15 feet apart and we tried to get close to 1 ohm resistance between them. This often required a copper sulfate solution to be poured into the rod holes. The reason for the exotic grounding had nothing to do with safety. Many of the systems utilized a RF transmitter running at 13 Mhz. The load for the RF transmitter was a plasma (ionized partial pressure gas) generated within the vacuum chamber. We had specially designed "matchboxes" that allowed load impedance matching of the 50 ohm transmitter output to the very low impedance of the plasma. Other systems used an electron beam operating at 10,000 volts. A stream of electrons are emitted from a filament and focused magnetically onto various metals or dielectrics that were vaporized by the beam and deposited on optics in very carefully controlled thicknesses. Anyway, there were often some arcs and sparks within the chamber with either of these deposition methods that would raise hell with some of the very sensitive measurement instruments. The elaborate grounding, using a wide conductor (flashing) is much better at RF and EMI quenching of the arcs. A simple, round ground wire has too much inductive reactance. It's only purpose on these systems was to serve as a safety ground. Sometimes we'd have to chase our tail for a while however because the use of both grounding systems sometimes generated a ground loop which only magnified the RFI problem. So you were running ungrounded delta. That is fairly rare and usually only for systems that are very intolerant of faults, like a glass plant where a power failure makes the whole place pretty much trash. I assume you had ground fault indicators since the first ground fault is "free". I have never actually seen ungrounded delta here. The other option is impedance grounding that grounds the system via a resistor, just to stabilize the voltage, not to provide any fault protection. You are right that there is no exception that allows the non current carrying parts of the system to be ungrounded. They are really trying to change that terminology to "bonded" to avoid confusion with the "grounded conductor" that we normally call the neutral and the "grounding electrode" that is your physical connection with earth. Article 250 may be the most misunderstood article in the whole NEC, hence the one I spent the most time studying. They are trying to redefine some of the terms to make it easier to understand because "ground" is such an all encompassing word that it misses the intent about half the time and when you actually start testing, it isn't even the same voltage from one place to another when you actually test with stakes in the dirt. I don't think the configuration I described is all that rare. In fact it's pretty common for industrial machine tool wiring for equipment that requires significant power. There are literally thousands of systems similar to the ones my company built, designed manufactured and installed by other companies in the USA and world wide, going back to the 1950's. We (and other US manufactures) follow(ed) the National Electric Code however there are some things that aren't even acknowledged, covered or would not be allowed (like the electron beam source application). Our installation crew got into a ****ing contest with a union electrician once regarding how the 10,000 volt leads to the feedthroughs were wired below the chamber baseplate. There is nothing in the code book that even comes close to covering anything like this. We had access to them protected by panel interlocks, vacuum interlocks and then the leads themselves are within plexiglass enclosures with "Danger - High Voltage" stickers on them. I think it scared the electrician and he raised an issue that temporarily shut down the installation of the system. It was resolved by the customer's facility engineering and was approved. There's a clause for situations like that in the code book that goes something like: "When the machine requirements and the code conflict, the machine requirements will govern". Every one of our technical proposals had that clause in it, along with pertinent ASME codes for pressure vessels, even though a vacuum chamber is not really a pressure vessel. During the many years I was in that industry there were no ASME codes for vacuum vessels. That's why two 8 inch flanges on some vacuum piping would be connected with 8, 3/4 inch bolts with nuts. Kinda overkill for vacuum piping but that's what the ASME code calls for. |
Flurries
On 1/5/2018 4:22 PM, wrote:
On Fri, 05 Jan 2018 15:40:14 -0500, wrote: On Fri, 5 Jan 2018 11:47:02 -0800 (PST), Its Me wrote: On Friday, January 5, 2018 at 2:15:45 PM UTC-5, wrote: On Fri, 5 Jan 2018 09:29:32 -0800 (PST), Its Me wrote: On Friday, January 5, 2018 at 11:49:34 AM UTC-5, wrote: On Fri, 5 Jan 2018 08:32:51 -0500 (EST), justan wrote: Wrote in message: My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? gallons of propane an hour What is involved in converting to propane? You remove the carb, install longer studs, slip the propane venturi over the studs and reinstall the carb. Then you mount the regulator, hook up the hoses and you are ready to rock. The whole thing takes less than an hour the first time and I bet I can do it in 15 minutes now. They give you the initial setting on the control block for nat gas or propane and you dial it in from there once you get it running. I may be able to improve the fuel consumption a little but I would rather be too rich than too lean. I have it pretty close tho. What are the advantages of running on propane other than the possibility of having a large, buried propane tank as your source? I have a 330 gallon buried tank, but at 8 gallons an hour and an ~80% fill, that's less than 2 days run time. That equates to about 20 gallons of gas, if my preacher math is correct. I may have slipped a decimal point on you. The gas to propane ratio is ~5:8. I had all of that stuff written down but I lost the paper. I just remembered the 8, not that it was 0.8 5 gallons of gas ran me about 10 hours and that took ~8 gallons of propane ... based on the gauge. I still have not refilled the tank so I do not have the actual number and since I don't have my log, I doubt I ever will know exactly what my burn rate was. The next time I feel like working on my generator, I have an hour meter I will be installing but it is hard to think about that stuff when the power is on ;-) Ah, gotcha. That makes much more sense. The propane is still more costly, but the ease of long term storage of large amounts far outweigh the costs. I keep saying that I'm going to buy a generator, but in the last ten years we've probably lost power for a total of 4 hours or so. Hard to justify it, until you need it. === Yes, but once you go into a multi day power outage a generator is a really nice thing to have. We're fortunate to have a good sized diesel generator on the boat with 500+ gallons of fuel typically. With a little red neck engineering we can power the entire house including the central air, stove and hot water heater. I have been here 34 years and Irma was the first time the power was out more than a day and that one day outage was Charley. The main advantage of propane for me is, it starts instantly and I can put it away again just by unplugging it. No draining carbs, running dry, stale gas etc. I also have the kit to run off of a 20# tank if I want to take it somewhere for a small job. The only precaution I noticed about "DIY" conversions was the lack of a detector to shut off the propane flow if the generator engine should stall. Otherwise you could be in the making for a grand experience. |
Flurries
On Friday, January 5, 2018 at 4:18:58 PM UTC-5, wrote:
On Fri, 5 Jan 2018 11:47:02 -0800 (PST), Its Me wrote: On Friday, January 5, 2018 at 2:15:45 PM UTC-5, wrote: On Fri, 5 Jan 2018 09:29:32 -0800 (PST), Its Me wrote: On Friday, January 5, 2018 at 11:49:34 AM UTC-5, wrote: On Fri, 5 Jan 2018 08:32:51 -0500 (EST), justan wrote: Wrote in message: My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? gallons of propane an hour What is involved in converting to propane? You remove the carb, install longer studs, slip the propane venturi over the studs and reinstall the carb. Then you mount the regulator, hook up the hoses and you are ready to rock. The whole thing takes less than an hour the first time and I bet I can do it in 15 minutes now. They give you the initial setting on the control block for nat gas or propane and you dial it in from there once you get it running. I may be able to improve the fuel consumption a little but I would rather be too rich than too lean. I have it pretty close tho. What are the advantages of running on propane other than the possibility of having a large, buried propane tank as your source? I have a 330 gallon buried tank, but at 8 gallons an hour and an ~80% fill, that's less than 2 days run time. That equates to about 20 gallons of gas, if my preacher math is correct. I may have slipped a decimal point on you. The gas to propane ratio is ~5:8. I had all of that stuff written down but I lost the paper. I just remembered the 8, not that it was 0.8 5 gallons of gas ran me about 10 hours and that took ~8 gallons of propane ... based on the gauge. I still have not refilled the tank so I do not have the actual number and since I don't have my log, I doubt I ever will know exactly what my burn rate was. The next time I feel like working on my generator, I have an hour meter I will be installing but it is hard to think about that stuff when the power is on ;-) Ah, gotcha. That makes much more sense. The propane is still more costly, but the ease of long term storage of large amounts far outweigh the costs. I keep saying that I'm going to buy a generator, but in the last ten years we've probably lost power for a total of 4 hours or so. Hard to justify it, until you need it. I didn't plan to myself but a guy made me an offer I couldn't refuse. 5.5KW Briggs NIB $300 Ask him if he has another one. :) |
Flurries
Mr. Luddite wrote:
On 1/5/2018 4:22 PM, wrote: On Fri, 05 Jan 2018 15:40:14 -0500, wrote: On Fri, 5 Jan 2018 11:47:02 -0800 (PST), Its Me wrote: On Friday, January 5, 2018 at 2:15:45 PM UTC-5, wrote: On Fri, 5 Jan 2018 09:29:32 -0800 (PST), Its Me wrote: On Friday, January 5, 2018 at 11:49:34 AM UTC-5, wrote: On Fri, 5 Jan 2018 08:32:51 -0500 (EST), justan wrote: Wrote in message: My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? gallons of propane an hour What is involved in converting to propane? You remove the carb, install longer studs, slip the propane venturi over the studs and reinstall the carb. Then you mount the regulator, hook up the hoses and you are ready to rock. The whole thing takes less than an hour the first time and I bet I can do it in 15 minutes now. They give you the initial setting on the control block for nat gas or propane and you dial it in from there once you get it running. I may be able to improve the fuel consumption a little but I would rather be too rich than too lean. I have it pretty close tho. What are the advantages of running on propane other than the possibility of having a large, buried propane tank as your source? I have a 330 gallon buried tank, but at 8 gallons an hour and an ~80% fill, that's less than 2 days run time. That equates to about 20 gallons of gas, if my preacher math is correct. I may have slipped a decimal point on you. The gas to propane ratio is ~5:8. I had all of that stuff written down but I lost the paper. I just remembered the 8, not that it was 0.8 5 gallons of gas ran me about 10 hours and that took ~8 gallons of propane ... based on the gauge. I still have not refilled the tank so I do not have the actual number and since I don't have my log, I doubt I ever will know exactly what my burn rate was. The next time I feel like working on my generator, I have an hour meter I will be installing but it is hard to think about that stuff when the power is on ;-) Ah, gotcha. That makes much more sense. The propane is still more costly, but the ease of long term storage of large amounts far outweigh the costs. I keep saying that I'm going to buy a generator, but in the last ten years we've probably lost power for a total of 4 hours or so. Hard to justify it, until you need it. === Yes, but once you go into a multi day power outage a generator is a really nice thing to have. We're fortunate to have a good sized diesel generator on the boat with 500+ gallons of fuel typically. With a little red neck engineering we can power the entire house including the central air, stove and hot water heater. I have been here 34 years and Irma was the first time the power was out more than a day and that one day outage was Charley. The main advantage of propane for me is, it starts instantly and I can put it away again just by unplugging it. No draining carbs, running dry, stale gas etc. I also have the kit to run off of a 20# tank if I want to take it somewhere for a small job. The only precaution I noticed about "DIY" conversions was the lack of a detector to shut off the propane flow if the generator engine should stall. Otherwise you could be in the making for a grand experience. The only problem I had with bad ground was a missing connection between the ground line and the neutral line . We had a float of 12 volts on the hot to neutral. So sometimes the disk drive would fail to start. |
Flurries
On Fri, 5 Jan 2018 16:32:19 -0500, "Mr. Luddite"
wrote: On 1/5/2018 2:06 PM, wrote: On Fri, 5 Jan 2018 12:28:51 -0500, "Mr. Luddite" wrote: On 1/5/2018 11:37 AM, wrote: On Fri, 5 Jan 2018 05:34:25 -0500, "Mr. Luddite" wrote: I agree the harmonic problem is just on wye but that is the most common configuration, 208 or 480. I think the problem first showed up on 480/277 wye systems where they had a building full of 277v electronic ballasts. Then it started showing up in those 208 systems that were feeding 120v lines in cubicles through the internal wiring with a 5 wire feeder as PCs started replacing terminals with ferro power supplies and space heaters. Delta is always funny stuff, depending on where or even if you land the ground. Corner grounded is probably the easiest to confuse the novice. It will look just like single phase until you get your meter out. (2 pole breakers, white wires etc) Not familiar with that. The majority of the systems we built were designed to run on 480v, 3 phase. All the main breakers, fused disconnects, motor starters, etc. were three pole. Ground was run separately. We used a dedicated control transformer in each power cabinet to generate whatever the low voltage control wiring was ... 120v in the early days but later 24 volt. IIRC, the control transformer on the 120v systems was a 480v/240v step down with a center tap, providing a neutral. Did you ground your 480 delta at all? If so where did the ground land? I understand your control circuit voltage can be 120 if you want. That is just a class 1 control circuit. Most people are familiar with class 2 but they are both controlled by the same article in the NEC. Class 1 just looks like regular line voltage circuits because it is not voltage or current limited like class 2 and 3. The center tapped 240 delta is commonly called "red leg" or "wild leg"because the corner between the center tapped windings will be 208v to ground. "Red" is a misnomer tho because the NEC requires the wire to be orange. That is very common in places where they want discount 3 phase and have a significant amount of single phase loads like those small industrial bays. The PoCo can do it with 2 transformers, generally the wild leg will be on a much smaller one. One "winding" is actually open. hence another name, "Delta Veep". http://gfretwell.com/electrical/red%...ansformers.jpg 99.99% of the time, if you see 3 transformers on the pole, it will be wye. but I have seen one place in Key West where they had red leg delta with 3 transformers. The only tip off was one was bigger than the other two and it was confirmed by analysing the wiring. http://gfretwell.com/electrical/Tran...%20_breath.jpg Yeah my wife thinks I am crazy too, taking pictures of transformers. Ground for the 480 Delta system service was run separately back to the physical (metallic) ground at the panel, usually via a 6 awg wire. Ground was not taken from any of the legs of the 3 phase Delta the way you have described. Many of the systems we built also had a RFI ground consisting of wide, copper flashing to two, 8' copper rods driven through the floor and into the ground. The rods were about 10-15 feet apart and we tried to get close to 1 ohm resistance between them. This often required a copper sulfate solution to be poured into the rod holes. The reason for the exotic grounding had nothing to do with safety. Many of the systems utilized a RF transmitter running at 13 Mhz. The load for the RF transmitter was a plasma (ionized partial pressure gas) generated within the vacuum chamber. We had specially designed "matchboxes" that allowed load impedance matching of the 50 ohm transmitter output to the very low impedance of the plasma. Other systems used an electron beam operating at 10,000 volts. A stream of electrons are emitted from a filament and focused magnetically onto various metals or dielectrics that were vaporized by the beam and deposited on optics in very carefully controlled thicknesses. Anyway, there were often some arcs and sparks within the chamber with either of these deposition methods that would raise hell with some of the very sensitive measurement instruments. The elaborate grounding, using a wide conductor (flashing) is much better at RF and EMI quenching of the arcs. A simple, round ground wire has too much inductive reactance. It's only purpose on these systems was to serve as a safety ground. Sometimes we'd have to chase our tail for a while however because the use of both grounding systems sometimes generated a ground loop which only magnified the RFI problem. So you were running ungrounded delta. That is fairly rare and usually only for systems that are very intolerant of faults, like a glass plant where a power failure makes the whole place pretty much trash. I assume you had ground fault indicators since the first ground fault is "free". I have never actually seen ungrounded delta here. The other option is impedance grounding that grounds the system via a resistor, just to stabilize the voltage, not to provide any fault protection. You are right that there is no exception that allows the non current carrying parts of the system to be ungrounded. They are really trying to change that terminology to "bonded" to avoid confusion with the "grounded conductor" that we normally call the neutral and the "grounding electrode" that is your physical connection with earth. Article 250 may be the most misunderstood article in the whole NEC, hence the one I spent the most time studying. They are trying to redefine some of the terms to make it easier to understand because "ground" is such an all encompassing word that it misses the intent about half the time and when you actually start testing, it isn't even the same voltage from one place to another when you actually test with stakes in the dirt. I don't think the configuration I described is all that rare. In fact it's pretty common for industrial machine tool wiring for equipment that requires significant power. There are literally thousands of systems similar to the ones my company built, designed manufactured and installed by other companies in the USA and world wide, going back to the 1950's. I don't know. Like I said I have never seen ungrounded delta but I know the guys to ask. I am still wondering if it was impedance grounded or corner grounded. They do not need to bring the grounded conductor out to distribution equipment, in fact we never did in computer rooms. It stopped at the service disconnect. We (and other US manufactures) follow(ed) the National Electric Code however there are some things that aren't even acknowledged, covered or would not be allowed (like the electron beam source application). Our installation crew got into a ****ing contest with a union electrician once regarding how the 10,000 volt leads to the feedthroughs were wired below the chamber baseplate. There is nothing in the code book that even comes close to covering anything like this. We had access to them protected by panel interlocks, vacuum interlocks and then the leads themselves are within plexiglass enclosures with "Danger - High Voltage" stickers on them. I think it scared the electrician and he raised an issue that temporarily shut down the installation of the system. It was resolved by the customer's facility engineering and was approved. There's a clause for situations like that in the code book that goes something like: "When the machine requirements and the code conflict, the machine requirements will govern". Every one of our technical proposals had that clause in it, along with pertinent ASME codes for pressure vessels, even though a vacuum chamber is not really a pressure vessel. During the many years I was in that industry there were no ASME codes for vacuum vessels. That's why two 8 inch flanges on some vacuum piping would be connected with 8, 3/4 inch bolts with nuts. Kinda overkill for vacuum piping but that's what the ASME code calls for. Once you get off into "equipment" the NEC is largely silent. For IBM, it stopped at the line plug although in places like Chicago the IBEW still wanted a taste of the labor (or all of it). |
Flurries
On Fri, 5 Jan 2018 16:36:21 -0500, "Mr. Luddite"
wrote: On 1/5/2018 4:22 PM, wrote: On Fri, 05 Jan 2018 15:40:14 -0500, wrote: On Fri, 5 Jan 2018 11:47:02 -0800 (PST), Its Me wrote: On Friday, January 5, 2018 at 2:15:45 PM UTC-5, wrote: On Fri, 5 Jan 2018 09:29:32 -0800 (PST), Its Me wrote: On Friday, January 5, 2018 at 11:49:34 AM UTC-5, wrote: On Fri, 5 Jan 2018 08:32:51 -0500 (EST), justan wrote: Wrote in message: My 5.5 KW burned about 0.5-0.6 GPH gasoline and more like 8 on propane running pretty much 24 hours a day at close to full load. Once I started running propane, it never turned off. I did trip the breaker now and then when the loads ganged up on me. ;-) 8 what? gallons of propane an hour What is involved in converting to propane? You remove the carb, install longer studs, slip the propane venturi over the studs and reinstall the carb. Then you mount the regulator, hook up the hoses and you are ready to rock. The whole thing takes less than an hour the first time and I bet I can do it in 15 minutes now. They give you the initial setting on the control block for nat gas or propane and you dial it in from there once you get it running. I may be able to improve the fuel consumption a little but I would rather be too rich than too lean. I have it pretty close tho. What are the advantages of running on propane other than the possibility of having a large, buried propane tank as your source? I have a 330 gallon buried tank, but at 8 gallons an hour and an ~80% fill, that's less than 2 days run time. That equates to about 20 gallons of gas, if my preacher math is correct. I may have slipped a decimal point on you. The gas to propane ratio is ~5:8. I had all of that stuff written down but I lost the paper. I just remembered the 8, not that it was 0.8 5 gallons of gas ran me about 10 hours and that took ~8 gallons of propane ... based on the gauge. I still have not refilled the tank so I do not have the actual number and since I don't have my log, I doubt I ever will know exactly what my burn rate was. The next time I feel like working on my generator, I have an hour meter I will be installing but it is hard to think about that stuff when the power is on ;-) Ah, gotcha. That makes much more sense. The propane is still more costly, but the ease of long term storage of large amounts far outweigh the costs. I keep saying that I'm going to buy a generator, but in the last ten years we've probably lost power for a total of 4 hours or so. Hard to justify it, until you need it. === Yes, but once you go into a multi day power outage a generator is a really nice thing to have. We're fortunate to have a good sized diesel generator on the boat with 500+ gallons of fuel typically. With a little red neck engineering we can power the entire house including the central air, stove and hot water heater. I have been here 34 years and Irma was the first time the power was out more than a day and that one day outage was Charley. The main advantage of propane for me is, it starts instantly and I can put it away again just by unplugging it. No draining carbs, running dry, stale gas etc. I also have the kit to run off of a 20# tank if I want to take it somewhere for a small job. The only precaution I noticed about "DIY" conversions was the lack of a detector to shut off the propane flow if the generator engine should stall. Otherwise you could be in the making for a grand experience. That is true but if the venturi isn't "sucking" there won't be much if any gas going through the regulator. It works pretty much like a SCUBA regulator. You have to use the "prime" button to get enough gas in the throat to start it. |
Flurries
On 1/6/2018 1:21 AM, wrote:
On Fri, 5 Jan 2018 16:32:19 -0500, "Mr. Luddite" wrote: On 1/5/2018 2:06 PM, wrote: On Fri, 5 Jan 2018 12:28:51 -0500, "Mr. Luddite" wrote: On 1/5/2018 11:37 AM, wrote: On Fri, 5 Jan 2018 05:34:25 -0500, "Mr. Luddite" wrote: I agree the harmonic problem is just on wye but that is the most common configuration, 208 or 480. I think the problem first showed up on 480/277 wye systems where they had a building full of 277v electronic ballasts. Then it started showing up in those 208 systems that were feeding 120v lines in cubicles through the internal wiring with a 5 wire feeder as PCs started replacing terminals with ferro power supplies and space heaters. Delta is always funny stuff, depending on where or even if you land the ground. Corner grounded is probably the easiest to confuse the novice. It will look just like single phase until you get your meter out. (2 pole breakers, white wires etc) Not familiar with that. The majority of the systems we built were designed to run on 480v, 3 phase. All the main breakers, fused disconnects, motor starters, etc. were three pole. Ground was run separately. We used a dedicated control transformer in each power cabinet to generate whatever the low voltage control wiring was ... 120v in the early days but later 24 volt. IIRC, the control transformer on the 120v systems was a 480v/240v step down with a center tap, providing a neutral. Did you ground your 480 delta at all? If so where did the ground land? I understand your control circuit voltage can be 120 if you want. That is just a class 1 control circuit. Most people are familiar with class 2 but they are both controlled by the same article in the NEC. Class 1 just looks like regular line voltage circuits because it is not voltage or current limited like class 2 and 3. The center tapped 240 delta is commonly called "red leg" or "wild leg"because the corner between the center tapped windings will be 208v to ground. "Red" is a misnomer tho because the NEC requires the wire to be orange. That is very common in places where they want discount 3 phase and have a significant amount of single phase loads like those small industrial bays. The PoCo can do it with 2 transformers, generally the wild leg will be on a much smaller one. One "winding" is actually open. hence another name, "Delta Veep". http://gfretwell.com/electrical/red%...ansformers.jpg 99.99% of the time, if you see 3 transformers on the pole, it will be wye. but I have seen one place in Key West where they had red leg delta with 3 transformers. The only tip off was one was bigger than the other two and it was confirmed by analysing the wiring. http://gfretwell.com/electrical/Tran...%20_breath.jpg Yeah my wife thinks I am crazy too, taking pictures of transformers. Ground for the 480 Delta system service was run separately back to the physical (metallic) ground at the panel, usually via a 6 awg wire. Ground was not taken from any of the legs of the 3 phase Delta the way you have described. Many of the systems we built also had a RFI ground consisting of wide, copper flashing to two, 8' copper rods driven through the floor and into the ground. The rods were about 10-15 feet apart and we tried to get close to 1 ohm resistance between them. This often required a copper sulfate solution to be poured into the rod holes. The reason for the exotic grounding had nothing to do with safety. Many of the systems utilized a RF transmitter running at 13 Mhz. The load for the RF transmitter was a plasma (ionized partial pressure gas) generated within the vacuum chamber. We had specially designed "matchboxes" that allowed load impedance matching of the 50 ohm transmitter output to the very low impedance of the plasma. Other systems used an electron beam operating at 10,000 volts. A stream of electrons are emitted from a filament and focused magnetically onto various metals or dielectrics that were vaporized by the beam and deposited on optics in very carefully controlled thicknesses. Anyway, there were often some arcs and sparks within the chamber with either of these deposition methods that would raise hell with some of the very sensitive measurement instruments. The elaborate grounding, using a wide conductor (flashing) is much better at RF and EMI quenching of the arcs. A simple, round ground wire has too much inductive reactance. It's only purpose on these systems was to serve as a safety ground. Sometimes we'd have to chase our tail for a while however because the use of both grounding systems sometimes generated a ground loop which only magnified the RFI problem. So you were running ungrounded delta. That is fairly rare and usually only for systems that are very intolerant of faults, like a glass plant where a power failure makes the whole place pretty much trash. I assume you had ground fault indicators since the first ground fault is "free". I have never actually seen ungrounded delta here. The other option is impedance grounding that grounds the system via a resistor, just to stabilize the voltage, not to provide any fault protection. You are right that there is no exception that allows the non current carrying parts of the system to be ungrounded. They are really trying to change that terminology to "bonded" to avoid confusion with the "grounded conductor" that we normally call the neutral and the "grounding electrode" that is your physical connection with earth. Article 250 may be the most misunderstood article in the whole NEC, hence the one I spent the most time studying. They are trying to redefine some of the terms to make it easier to understand because "ground" is such an all encompassing word that it misses the intent about half the time and when you actually start testing, it isn't even the same voltage from one place to another when you actually test with stakes in the dirt. I don't think the configuration I described is all that rare. In fact it's pretty common for industrial machine tool wiring for equipment that requires significant power. There are literally thousands of systems similar to the ones my company built, designed manufactured and installed by other companies in the USA and world wide, going back to the 1950's. I don't know. Like I said I have never seen ungrounded delta but I know the guys to ask. I am still wondering if it was impedance grounded or corner grounded. They do not need to bring the grounded conductor out to distribution equipment, in fact we never did in computer rooms. It stopped at the service disconnect. We (and other US manufactures) follow(ed) the National Electric Code however there are some things that aren't even acknowledged, covered or would not be allowed (like the electron beam source application). Our installation crew got into a ****ing contest with a union electrician once regarding how the 10,000 volt leads to the feedthroughs were wired below the chamber baseplate. There is nothing in the code book that even comes close to covering anything like this. We had access to them protected by panel interlocks, vacuum interlocks and then the leads themselves are within plexiglass enclosures with "Danger - High Voltage" stickers on them. I think it scared the electrician and he raised an issue that temporarily shut down the installation of the system. It was resolved by the customer's facility engineering and was approved. There's a clause for situations like that in the code book that goes something like: "When the machine requirements and the code conflict, the machine requirements will govern". Every one of our technical proposals had that clause in it, along with pertinent ASME codes for pressure vessels, even though a vacuum chamber is not really a pressure vessel. During the many years I was in that industry there were no ASME codes for vacuum vessels. That's why two 8 inch flanges on some vacuum piping would be connected with 8, 3/4 inch bolts with nuts. Kinda overkill for vacuum piping but that's what the ASME code calls for. Once you get off into "equipment" the NEC is largely silent. For IBM, it stopped at the line plug although in places like Chicago the IBEW still wanted a taste of the labor (or all of it). We built and installed a custom system for the deposition of hard carbon (diamond-like coating) onto M1 tank infrared windows. It used a RF power supply as part of the process. It was installed at a company a couple of miles or so from O'Hare Airport and the local inspector demanded that it needed to be CE Certified which was news to me. He inspected all the components we had purchased and used for it ... down to the small air actuator valves but when he asked what it was used for he just signed off on the whole thing. |
Flurries
On 1/6/2018 1:21 AM, wrote:
On Fri, 5 Jan 2018 16:32:19 -0500, "Mr. Luddite" wrote: On 1/5/2018 2:06 PM, wrote: On Fri, 5 Jan 2018 12:28:51 -0500, "Mr. Luddite" wrote: On 1/5/2018 11:37 AM, wrote: On Fri, 5 Jan 2018 05:34:25 -0500, "Mr. Luddite" wrote: I agree the harmonic problem is just on wye but that is the most common configuration, 208 or 480. I think the problem first showed up on 480/277 wye systems where they had a building full of 277v electronic ballasts. Then it started showing up in those 208 systems that were feeding 120v lines in cubicles through the internal wiring with a 5 wire feeder as PCs started replacing terminals with ferro power supplies and space heaters. Delta is always funny stuff, depending on where or even if you land the ground. Corner grounded is probably the easiest to confuse the novice. It will look just like single phase until you get your meter out. (2 pole breakers, white wires etc) Not familiar with that. The majority of the systems we built were designed to run on 480v, 3 phase. All the main breakers, fused disconnects, motor starters, etc. were three pole. Ground was run separately. We used a dedicated control transformer in each power cabinet to generate whatever the low voltage control wiring was ... 120v in the early days but later 24 volt. IIRC, the control transformer on the 120v systems was a 480v/240v step down with a center tap, providing a neutral. Did you ground your 480 delta at all? If so where did the ground land? I understand your control circuit voltage can be 120 if you want. That is just a class 1 control circuit. Most people are familiar with class 2 but they are both controlled by the same article in the NEC. Class 1 just looks like regular line voltage circuits because it is not voltage or current limited like class 2 and 3. The center tapped 240 delta is commonly called "red leg" or "wild leg"because the corner between the center tapped windings will be 208v to ground. "Red" is a misnomer tho because the NEC requires the wire to be orange. That is very common in places where they want discount 3 phase and have a significant amount of single phase loads like those small industrial bays. The PoCo can do it with 2 transformers, generally the wild leg will be on a much smaller one. One "winding" is actually open. hence another name, "Delta Veep". http://gfretwell.com/electrical/red%...ansformers.jpg 99.99% of the time, if you see 3 transformers on the pole, it will be wye. but I have seen one place in Key West where they had red leg delta with 3 transformers. The only tip off was one was bigger than the other two and it was confirmed by analysing the wiring. http://gfretwell.com/electrical/Tran...%20_breath.jpg Yeah my wife thinks I am crazy too, taking pictures of transformers. Ground for the 480 Delta system service was run separately back to the physical (metallic) ground at the panel, usually via a 6 awg wire. Ground was not taken from any of the legs of the 3 phase Delta the way you have described. Many of the systems we built also had a RFI ground consisting of wide, copper flashing to two, 8' copper rods driven through the floor and into the ground. The rods were about 10-15 feet apart and we tried to get close to 1 ohm resistance between them. This often required a copper sulfate solution to be poured into the rod holes. The reason for the exotic grounding had nothing to do with safety. Many of the systems utilized a RF transmitter running at 13 Mhz. The load for the RF transmitter was a plasma (ionized partial pressure gas) generated within the vacuum chamber. We had specially designed "matchboxes" that allowed load impedance matching of the 50 ohm transmitter output to the very low impedance of the plasma. Other systems used an electron beam operating at 10,000 volts. A stream of electrons are emitted from a filament and focused magnetically onto various metals or dielectrics that were vaporized by the beam and deposited on optics in very carefully controlled thicknesses. Anyway, there were often some arcs and sparks within the chamber with either of these deposition methods that would raise hell with some of the very sensitive measurement instruments. The elaborate grounding, using a wide conductor (flashing) is much better at RF and EMI quenching of the arcs. A simple, round ground wire has too much inductive reactance. It's only purpose on these systems was to serve as a safety ground. Sometimes we'd have to chase our tail for a while however because the use of both grounding systems sometimes generated a ground loop which only magnified the RFI problem. So you were running ungrounded delta. That is fairly rare and usually only for systems that are very intolerant of faults, like a glass plant where a power failure makes the whole place pretty much trash. I assume you had ground fault indicators since the first ground fault is "free". I have never actually seen ungrounded delta here. The other option is impedance grounding that grounds the system via a resistor, just to stabilize the voltage, not to provide any fault protection. You are right that there is no exception that allows the non current carrying parts of the system to be ungrounded. They are really trying to change that terminology to "bonded" to avoid confusion with the "grounded conductor" that we normally call the neutral and the "grounding electrode" that is your physical connection with earth. Article 250 may be the most misunderstood article in the whole NEC, hence the one I spent the most time studying. They are trying to redefine some of the terms to make it easier to understand because "ground" is such an all encompassing word that it misses the intent about half the time and when you actually start testing, it isn't even the same voltage from one place to another when you actually test with stakes in the dirt. I don't think the configuration I described is all that rare. In fact it's pretty common for industrial machine tool wiring for equipment that requires significant power. There are literally thousands of systems similar to the ones my company built, designed manufactured and installed by other companies in the USA and world wide, going back to the 1950's. I don't know. Like I said I have never seen ungrounded delta but I know the guys to ask. I am still wondering if it was impedance grounded or corner grounded. They do not need to bring the grounded conductor out to distribution equipment, in fact we never did in computer rooms. It stopped at the service disconnect. Ah .. I think I see the confusion. Yes, the secondary of a 3 wire, 480v delta service will usually have one leg tied to *earth* ground but it's not used as a current carrying conductor. The primary side of a 3 wire service transformer is not grounded. There is also a 4 wire delta service that includes a neutral from the service side. You are talking the service side. I am talking the load side. The equipment we built was powered by the 3 wire, 480v legs for power to the various motors and heaters. A safety ground is run back to the service panel that is tied to earth ground. It's why we used a separate transformer to generate the single phase, 120v and 24v control voltages used for the instruments and control switches. |
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