How to fix a dead welder?

[mgoncalves]

I just got an arc welder from my neighbor yesterday. When the switch is turned on it blows every breaker down the line, a very bad dead short obviously. Now, I ohm'd out the plug and do not get any continuity from ground to either hot leg with the switch in both off and on. I do get continuity between the two legs with the switch on, which to my understanding is normal.



How do I track down a short in a welder? I don't really know how it works, so it's kind of hard to diagnose.



Matt

 

[Rotty]

Use a multimeter or ohmmeter. It should be a few ohms from each of the two hot legs. No continuity from either hot leg to gnd.

Try that... .

 

[GKulp]

my thoughts about your welder

From what you measured, you don't have a short from either side

of the input power wiring to ground. That is good! However, you

might have a short in the windings of the input transformer. You

measured some amount of resistance so that means that some of

the windings are okay. But, are all the windings ok? The blowing

fuse problem suggests that the resistance of the windings is too

low, which suggests that there is some sort of short in the

windings. I would suggest that you contact the manufacturer

of the welder and ask what the resistance of the transformer

should be. If you have somewhat less resistance than what

they specifiy, then I think you might need a new transformer.

Maybe, that's not too expensive, provided you can buy it and

replace it yourself. Good luck with the repairs.



George

 

[KBennett]

I think George has this one nailed, probably a short on the primary side of the transformer or the internal wiring. Take the cover off and see if there is anything that looks out of order. Traditional AC welders are pretty simple, just a transformer with a switch to select the tap.