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Microwave problem with XPOWER 1000 Inverter
I just purchased a Tappan 550W microwave that consumes 850W. I
also purchased a Xantrex Xpower 1000W inverter (modified sine wave). About 20% of the time, when I start the microwave, the light turns on, the turn table starts to rotate, and just as the magnetron starts up, the microwave shuts off. The microwave seems to have lost power since the clock resets. The other 80% of the time, the microwave works fine. Once it successfully starts up, it will run continuously without a problem. The inverter has a continuous rating of 1000W with a peek output of 2000W. I can't imagine that the microwave ever uses this much power to start. The fault light on the inverter does NOT come on. I have 2 large deep cycle batteries connected in parallel. They are in excellent condition and provide over 260AH. I have connected the inverter directly to the batteries with 2 AWG battery wire that I purchased at the auto store. Is there a problem with the microwave or inverter? Should I buy a more powerful inverter? Thanks Brent |
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We run a 1000W consumption microwave (600W output) on our 1000W
Statpower Inverter (sine wave). Had no trouble with either. Lyn & Tony S/V Ambrosia |
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"Comcast" wrote in message
... I just purchased a Tappan 550W microwave that consumes 850W. I also purchased a Xantrex Xpower 1000W inverter (modified sine wave). About 20% of the time, when I start the microwave, the light turns on, the turn table starts to rotate, and just as the magnetron starts up, the microwave shuts off. The microwave seems to have lost power since the clock resets. The other 80% of the time, the microwave works fine. Once it successfully starts up, it will run continuously without a problem. The inverter has a continuous rating of 1000W with a peek output of 2000W. I can't imagine that the microwave ever uses this much power to start. The inrush current of a large transformer can be 5 to 25 times the nominal current. And that is when fed with a sinewave current. With a modified sineware (which is just a square wave which stays on 0-V for some time, every cycle), the inrush current can be much higher. Meindert |
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Comcast wrote:
I just purchased a Tappan 550W microwave that consumes 850W. I also purchased a Xantrex Xpower 1000W inverter (modified sine wave). snip snip Is there a problem with the microwave or inverter? Should I buy a more powerful inverter? Some types of electrical or electronic equipments do not work or do not work well on modified sine wave inverters. If you look in your manual or at the Xantrex web site, it will tell you what those are. That may be your problem. If it is, a pure sine wave inverter will cure it. Guess what? It may be time to throw another bucket full of money into your "hole in the water". :) Jack -- Jack Erbes in Ellsworth, Maine, USA - jackerbes at adelphia dot net (also receiving email at jacker at midmaine.com) |
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It sounds like the microwave is tripping off on undervoltage. I'd be
looking at my 12 volt connections, as that is the usual source of the problem. Depending on the length of the run, that #2 wire may be a bit small. An easy test is to plug in a low wattage bulb to the inverter and watch how much it dims as the magnetron comes up to speed. You might also try running the system with the engine running (assuming a MH) or a high power charger in place to see if the added voltage will help. FWIW, I run a 600 watt microwave from a 1000 watt Vector inverter with no problems at all. I chose a microwave with a mechanical timer so as to avoid all those glitch problems. John On Wed, 23 Feb 2005 01:54:01 -0800, "Comcast" wrote: I just purchased a Tappan 550W microwave that consumes 850W. I also purchased a Xantrex Xpower 1000W inverter (modified sine wave). About 20% of the time, when I start the microwave, the light turns on, the turn table starts to rotate, and just as the magnetron starts up, the microwave shuts off. The microwave seems to have lost power since the clock resets. The other 80% of the time, the microwave works fine. Once it successfully starts up, it will run continuously without a problem. The inverter has a continuous rating of 1000W with a peek output of 2000W. I can't imagine that the microwave ever uses this much power to start. The fault light on the inverter does NOT come on. I have 2 large deep cycle batteries connected in parallel. They are in excellent condition and provide over 260AH. I have connected the inverter directly to the batteries with 2 AWG battery wire that I purchased at the auto store. Is there a problem with the microwave or inverter? Should I buy a more powerful inverter? Thanks Brent --- John De Armond http://www.johngsbbq.com http://neonjohn.blogspot.com -- NEW! Cleveland, Occupied TN |
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On Wed, 23 Feb 2005 11:45:14 -0500, Neon John
wrote: It sounds like the microwave is tripping off on undervoltage. I'd be looking at my 12 volt connections, as that is the usual source of the problem. Depending on the length of the run, that #2 wire may be a bit small. ============================= I agree that #2 wire is marginal at best. You are pulling well over 100 peak amps and voltage loss in the cable increases as the square of current flow. I'd sugggest something like 2/0 cable both to the inverter and for your battery parallel straps. It is true however that some devices just refuse to run on modified sine wave power. We had to try several different brands of electric blankets before we found one that worked. |
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Wayne.B wrote in
: It is true however that some devices just refuse to run on modified sine wave power. We had to try several different brands of electric blankets before we found one that worked. Oh, Wayne. I just gotta hear all about your house battery banks and charging system. How many amp-hours are aboard to run electric blankets and the other loads all night? Thanks..... (Nothing is funnier than a boater with a new 4KW inverter carrying his electric heater down the dock with that knowing smile on his face....) |
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On Thu, 24 Feb 2005 11:46:01 GMT, Larry W4CSC wrote:
Wayne.B wrote in : It is true however that some devices just refuse to run on modified sine wave power. We had to try several different brands of electric blankets before we found one that worked. Oh, Wayne. I just gotta hear all about your house battery banks and charging system. How many amp-hours are aboard to run electric blankets and the other loads all night? I just looked at the tag on my king-size electric blanket. It draws 200 watts. That'd be about 16.67 amps at full load from the battery. Not many people would use a king size bed in an RV. More like a twin or regular. I'd guesstimate the draw to be more in the 60 watt range or 5 amps. This corresponds well to my 12 volt electric throw that I use that draws 3.5 amps. Remember that these things are thermostatically controlled so they don't run all the time. That makes the actual situation better than it looks. I have a couple of Group 29 batteries in my rig and have no problem running the blanket, the furnace and other loads for a day at a time. According to the E-meter, I'll typically use 80 ah per 24 hour period in the winter. (Nothing is funnier than a boater with a new 4KW inverter carrying his electric heater down the dock with that knowing smile on his face....) Yup. Old rule of thumb, a gallon of gas is about the energy equivalent of about 1000 lbs of lead-acid batteries. John --- John De Armond http://www.johngsbbq.com http://neonjohn.blogspot.com -- NEW! Cleveland, Occupied TN |
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Neon John wrote in
: (Nothing is funnier than a boater with a new 4KW inverter carrying his electric heater down the dock with that knowing smile on his face....) Yup. Old rule of thumb, a gallon of gas is about the energy equivalent of about 1000 lbs of lead-acid batteries. John Thanks. Good rule of thumb. http://www.fleetsubmarine.com/battery.html |
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On Thu, 24 Feb 2005 11:46:01 GMT, Larry W4CSC wrote:
How many amp-hours are aboard to run electric blankets and the other loads all night? ====================================== It's not really a problem believe it or not. On our old boat the house bank was 4 golf cart batts in series-parallel, total capacity of 440 A-H, usable capacity about 150 A-H. We had a 7.5 KW genset so recharge was never a problem. The electric blanket has a peak load of 300 watts translating to about 30 amps at 12 v. Duty cycle is about 50% on a chilly 50 degree night in the north east. So for 8 hours of sleep we were pulling down about 120 A-H for the blanket (15 x 8), and maybe another 30 A-H for the fridge. Never had a problem. The batts were 3+ years old when I sold the boat and still going strong. For the new boat (GB49 trawler), I plan a house bank made up of individual 2 volt cells bolted together. It will weigh close to 1,000 lbs but that's not really an issue on a boat that weighs 60,000 fully loaded. Total capacity will be over 1,000 A-H with usable capacity greater than 350. Those 2 volt cells are guaranteed for 10 years so they may turn out to be the last battery I ever buy. Recharge will be via a high power inverter/charger, 20KW generator, and/or high capacity alternators. |
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