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#1
posted to rec.boats.electronics
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Varistor to shield voltage spikes
Hi group,
I want to use a welding machine on board and power it with my onboard 6 kW generator. The welding machine is a AC/DC HF-TIG with a lot of electronics inside. I have no documentation of my generator so I wanted to deal with the possibility of voltage spikes fi directly after stopping the welding-arc. My ships chandler gave me the following advice: In the power cord add an automatic fuse. Directlly after the fuse connect the phase and the null using a 235v Varistor. Under 235 volts it'll maintain high resistance and all will function normally. When the voltage exceeds 235 it will short circuit and the fuse will break the connection. What do you think of this setup. Will it operate fast enough to really prevent a voltage spike to reach my welding machine? Regards, Len, S/v Present |
#2
posted to rec.boats.electronics
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Varistor to shield voltage spikes
Silly me....I'd just disconnect the boat from the genset while I was
using the welder. Switch off the boat's breaker and run the welder directly from an outlet on the genset, even if you have to add it. KISS....(c; Len wrote in : Hi group, I want to use a welding machine on board and power it with my onboard 6 kW generator. The welding machine is a AC/DC HF-TIG with a lot of electronics inside. I have no documentation of my generator so I wanted to deal with the possibility of voltage spikes fi directly after stopping the welding-arc. My ships chandler gave me the following advice: In the power cord add an automatic fuse. Directlly after the fuse connect the phase and the null using a 235v Varistor. Under 235 volts it'll maintain high resistance and all will function normally. When the voltage exceeds 235 it will short circuit and the fuse will break the connection. What do you think of this setup. Will it operate fast enough to really prevent a voltage spike to reach my welding machine? Regards, Len, S/v Present |
#3
posted to rec.boats.electronics
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Varistor to shield voltage spikes
Hi Larry, thanks for responding, mate.
I do use an outlet directly off the genset. I wouldn't weld via the ships net... might fry the combined charger/inverter. Point is the genset may deliver voltage spikes (according to anyone here I speak to) when I use it to operate the welder. Particularly when I stop the welding-arc the genset could give a surge. I use the varistor/fuse to shut the power off when voltage exceeds 235v but I wonder if this really protects the welder... I mean when the varistor senses 235 it shortcircuits but that takes time. In this time only a superb being knows what can happen...or? Thanks, Len. On Fri, 13 Jan 2006 08:17:17 -0500, Larry wrote: Silly me....I'd just disconnect the boat from the genset while I was using the welder. Switch off the boat's breaker and run the welder directly from an outlet on the genset, even if you have to add it. KISS....(c; Len wrote in : Hi group, I want to use a welding machine on board and power it with my onboard 6 kW generator. The welding machine is a AC/DC HF-TIG with a lot of electronics inside. I have no documentation of my generator so I wanted to deal with the possibility of voltage spikes fi directly after stopping the welding-arc. My ships chandler gave me the following advice: In the power cord add an automatic fuse. Directlly after the fuse connect the phase and the null using a 235v Varistor. Under 235 volts it'll maintain high resistance and all will function normally. When the voltage exceeds 235 it will short circuit and the fuse will break the connection. What do you think of this setup. Will it operate fast enough to really prevent a voltage spike to reach my welding machine? Regards, Len, S/v Present |
#4
posted to rec.boats.electronics
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Varistor to shield voltage spikes
Len wrote in
: Point is the genset may deliver voltage spikes (according to anyone here I speak to) when I use it to operate the welder. Particularly If your welder were hooked to the genset as you say, then simply disconnect the boat from the genset by turning off the boat's main AC breaker at the panel until you're done with the welder. No surge makes it through an open breaker. The boat won't sink if it doesn't have AC power for a couple of hours while you're welding..(c; |
#5
posted to rec.boats.electronics
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Varistor to shield voltage spikes
On Fri, 13 Jan 2006 19:42:30 -0500, Larry wrote:
If your welder were hooked to the genset as you say, then simply disconnect the boat from the genset by turning off the boat's main AC breaker at the panel until you're done with the welder. No surge makes it through an open breaker. The boat won't sink if it doesn't have AC power for a couple of hours while you're welding..(c; Sorry Larry, didn't make myself clear enough. The boat _is_ shut off... I want to protect the welder's electronics. The d**ned thing is expensive. TIA, Len. |
#6
posted to rec.boats.electronics
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Varistor to shield voltage spikes
Len wrote in
: Sorry Larry, didn't make myself clear enough. The boat _is_ shut off... I want to protect the welder's electronics. The d**ned thing is expensive. The welder's electronics runs off a regulated power supply that already HAS circuit protection to keep the welder manufacturer out of the welder repair business. Welders are lucky if they get 80% of their spec voltage in a car shop...(c; Don't think so? Call the manufacturer or send him an email and ask 'em. |
#7
posted to rec.boats.electronics
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Varistor to shield voltage spikes
On Sat, 14 Jan 2006 07:53:29 -0500, Larry wrote:
The welder's electronics runs off a regulated power supply that already HAS circuit protection to keep the welder manufacturer out of the welder repair business. Welders are lucky if they get 80% of their spec voltage in a car shop...(c; Don't think so? Call the manufacturer or send him an email and ask 'em. I did. But I guess these pimplefaced youngsters that call themselves full blown sales-people don't know anything usefull and therefor tend to avoid any just ANY risk of being accountable. But what do you think of the varistor/fuse setup? I also want to use it in the incoming shore connection. Some shore connections are generator powered. That means there is a risk of the null hanging a bit loose what may cause v-spikes also. Would this setup protect my combined inverter charger in your opinion? CU, Len. |
#8
posted to rec.boats.electronics
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Varistor to shield voltage spikes
Len wrote:
But what do you think of the varistor/fuse setup? I also want to use it in the incoming shore connection. Some shore connections are generator powered. That means there is a risk of the null hanging a bit loose what may cause v-spikes also. Would this setup protect my combined inverter charger in your opinion? Destructive transients are done in microseconds. Fuses take tens or hundreds of milliseconds just to consider tripping. Varistor life expectancy is defined by a parameter called joules. And then you must define the type of transient - longitudinal or transverse. The most damning part of your theory is no numbers. With numbers, you have far more to consider. Properly noted is that electronics already have internal protection. So your only question means you must first define how bad that generator really is. Again, get numbers - specifications. Without first defining what you are protecting from, then no one can provide anything but wild speculation - Rush Limbaugh type response. |
#9
posted to rec.boats.electronics
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Varistor to shield voltage spikes
On 14 Jan 2006 17:18:24 -0800, "w_tom" wrote:
Len wrote: But what do you think of the varistor/fuse setup? I also want to use it in the incoming shore connection. Some shore connections are generator powered. That means there is a risk of the null hanging a bit loose what may cause v-spikes also. Would this setup protect my combined inverter charger in your opinion? Destructive transients are done in microseconds. Fuses take tens or hundreds of milliseconds just to consider tripping. Varistor life expectancy is defined by a parameter called joules. And then you must define the type of transient - longitudinal or transverse. The most damning part of your theory is no numbers. With numbers, you have far more to consider. Properly noted is that electronics already have internal protection. So your only question means you must first define how bad that generator really is. Again, get numbers - specifications. Without first defining what you are protecting from, then no one can provide anything but wild speculation - Rush Limbaugh type response. Wow, of course, thats it, get numbers and specs.... Why didn't I think of that???? |
#10
posted to rec.boats.electronics
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Varistor to shield voltage spikes
Len wrote in
: I did. But I guess these pimplefaced youngsters that call themselves full blown sales-people don't know anything usefull and therefor tend to avoid any just ANY risk of being accountable. It's called creating an "implied warranty of suitability for a particular purpose". If you sell can openers and, in your zeal to get the sale, tell the "consumer" (legal term in the law) that this can opener will open any can that contains food, you have created an implied warranty of suitabilitiy for a particular purpose. If the item doesn't perform TO THE CONSUMER'S SATISFACTION, the consumer can demand replacement or refund. So, it's best to tell your sales people to keep their big mouths shut and tell the "consumer" as little about the defective can openers you sell as possible, making no promises it will open any can at all. http://www.ftc.gov/bcp/conline/pubs/...s/warranty.htm Every consumer should read this FTC manual. It explains to the seller what the implied warranties HE CANNOT JUST DECLINE AWAY on his limited warranty wallpaper are and what his responsibility to the consumer is. Great reading if you have a lemon...(c; Unless the manufacturer can talk the FTC into a waiver, the Magnusson-Moss Warranty Protection Act (15USC50 section 2300) is in full force. It's even written in English, for a change, and is very specific, no matter what bull**** the dealer/store says. http://www.law.cornell.edu/uscode/ht..._15_10_50.html The part that worked for me is: http://www.law.cornell.edu/uscode/ht...5_00002304---- 000-.html Little paragraph a4 reads, interestingly enough: "(4) if the product (or a component part thereof) contains a defect or malfunction after a reasonable number of attempts by the warrantor to remedy defects or malfunctions in such product, such warrantor must permit the consumer to elect either a refund for, or replacement without charge of, such product or part (as the case may be). The Commission may by rule specify for purposes of this paragraph, what constitutes a reasonable number of attempts to remedy particular kinds of defects or malfunctions under different circumstances. If the warrantor replaces a component part of a consumer product, such replacement shall include installing the part in the product without charge." Notice it says "MUST PERMIT THE CONSUMER TO ELECT", not the dealer or the manufacturer's weasles. I think it could easily be used on those defective boats you're all buying they tell you they can't or won't fix. The judges tell them 3 attempts or 30 days....all the time. The manufacturers have a buzzword to explain it all away. They call it "buyer's remorse", placing all the blame on the buyers. My attorney disagreed....(c; |
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