Dont want to blow up my welder.

[Neil Deaves]

HI i will get through the preamble as quickly as poss. I need help because i'm an ordinary person and not made of money.
My problem is

I have an inverter welder .
i need to use to repair my project car in a place with no mains supply.
inverter welders are well known to blow up on portable generators possibly because of supply variations.
i cant afford an inverter generator. i can just afford a used genny.
my welder needs 230v, 50 hz at max 21 amp but i could get by on about 16 amp.
i've thought about trying to find a used single phase 230v to 230v motor inverter /speed controller would either work
any other suggestions welcome, as a mech eng i'm happy to make or adapt anything, problem always is money and lack of maths

Thanks for any help

 

[duke37]

I do not understand the story. What you need is an alternator capable of 5kW plus.
A welder is a horrible load and an alternator may not be able to handle the variations. Also the invertor rectifies the mains which distorts the waveform. One alternator that i played with needed a 2kW resistive load to make it behave.
You will need a 10kW engine to give a reasonably constant speed. If you have a tractor, then a PTO alternator would be my favorite solution.

My brother used an aircraft DC generator driven by a tractor. Voltage was controlled by engine speed and current with yards of iron wire resistors. This Heath Robinson system needed very sophisticated driving which I never managed.

 

[Tha fios agaibh]

The welder is a horrible load because it's essentially a short circuit every time you strike an arc.
I agree with duke37 that you need upwards of 5kw. It's doubtful 16amps is enough. I wouldn't chance it. I would go with at least 7kw.
I don't see it being less expensive using an alternator either.

It's a lot slower but you could always weld with an oxy/acetylene torch.