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Spot Welder Run Off Generator

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#1 Scott Brown

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Posted 06 May 2019 - 01:53 PM

Does anyone run there spot welder off a generator if so what generator do you have.

#2 humph


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Posted 06 May 2019 - 03:31 PM

My spot welder constantly trips a 13amp supply, needs a 16amp. Never run it off a genny.

#3 Scott Brown

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Posted 06 May 2019 - 04:18 PM

My garage is a distance from the house so running a new power cable would cost a lot of money

#4 tiger99


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Posted 18 May 2019 - 12:23 AM

So would a large generator.


Check the actual power requirements of your spot welder, and anything else such as lighting that you need at the same time, and maybe someone can give you better advice. But generally generators don't like heavy pulsating loads, and need to be rated much higher than the welder. An old-fashioned diesel generator with a very heavy flywheel is going to be better than a modern lightweight thing with electronic speed control. If the regulator in the alternator can't keep up with the pulses drawn by the welder, the voltage drops considerably as the weld begins, the regulator starts to increase the alternator field current to correct it, probably gets up to near maximum, the weld ends and current drops to zero, but the field current is still at maximum so the alternator generates a massive overvoltage, and BANG!


It is like subjecting a car alternator to many severe load dumps.


With a crude, oversized  diesel, and primitive voltage regulation, the kinetic energy in the flywheel should be sufficient to complete a weld, The engine may grunt, but not stall. 


Think about maybe a 10kVA generator, which will be heavy. But the good news is that the same generator may be suitable for most MIG and TIG welders too.


But please don't do anything without asking your suppliers to confirm that your proposed equipment will all work together.

#5 Ethel


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Posted 18 May 2019 - 10:09 AM

There are welder generators for constuction sites. Expect they'd blow holes in car panels big enough to fit RSJ's through, but it's an avenue of enquiry. 


Don't know your specific circumstances but a run of SWA cable could cost you about £3 a metre. You'd have to do some calculations, but if you can go that route it's likely to be your cheapest option if it's within 100m or so. 

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