Based on your description there should be 2 contactors. One is the contactor that controls power to the welder primary winding, this one should be quite large compared to the other one, the other controls the 24 volt (most common) supply to the wire feed speed control board and gas solenoid. If you do have 2 of these contactors, the 24 volt contactor may supply the control current to the larger contactor..
If blowing out the cabinet has not helped, and at this point it is not likely, the 24 volt contactor should be replaced. If a sealed one is available I would upgrade to that style. The ratings should be embossed on the contactor somewhere, otherwise your control voltage should be 24 volts, use a meter just make sure you are in that range, US, UK and Euro standard share some common specs. You may have a 2 pole or 3 pole type- it depends if the gas solenoid is powered off the same pole as the motor control board, or if it is powered by it's own pole. These would be the "N/O" contacts, and all would have current supplied by the 24 volt supply/control supply. The larger contact coil winding would be on it's own pole. Contacts should be rated at 15 Amps minimum
Replacing both contactors at the same time if so equipped is a cost effective bit of maintanence.
If you have only the single 24 volt contactor, the tip will be live at all times and it will only be the gas and the wire feed control board that would be switched by the contactor.
Again, based on description, I would replace the 24 volt contactor. Contacts should be rated at 15 Amps minimum
I would also just check the gas solenoid with a jumper wire to make sure it opened and closed as it should.
Feb 21, 2012 |