Unimig 375S auxilliary transformer specs?

[bcg1976]

Hi,

I have an old 375S mig that has decided to turn it's auxilliary transformer into carbon.

Would anyone know the specs on this part?

It's unimig part number 29080142.

The part from our friends at unimig is approaching $500. Which is obviously an uneconomical fix.

Any leads appreciated.

Thanks,
Brad

 

[RebarJunkie]

That’s a tough break, but you are right to look for a cheaper fix than buying the original part. That Uni-Mig KT-50 wire feeder is part of a larger transformer-based system, like the old 375S you mentioned.

The auxiliary transformer mainly supplies low voltage AC power to the control board (PCB), the wire feed motor, and the gas solenoid valve. A local electrical or transformer supplier might be able to rewind the old core for less than the new part, or they could sell you a generic control transformer with the right specs. You can take the burnt one in and ask them to match the output voltage and VA rating. Since the KT-50 wire feeder was used on several Uni-Mig Workshop Series models, like the 270 SWF and 425 SWF, you might find a used part from a welder that is being wrecked for parts. When replacing it, make sure the replacement matches the output voltage and has the proper VA rating or higher. Using a lower VA rating will just burn out the new transformer quickly.

It is frustrating when a small part costs so much. But you can likely fix it for much less if you can confirm the exact secondary voltage.