Noob question about welders

admin

I apologize of this question is moronic, but I just have to know:What, exactly, is the purpose of the CONTACTOR in a welding machine.I have a vague 'idea', but I would appreciate a proper explanation. My "ideas" have gotten me into trouble occasionally...-andy-
Reply:The contactor is a heavy duty switch, it is usually wired in series with the input side of the welding transformer. The “Trigger” on the mig torch energizes the contactor coil, closing the open points and switches power to the welding transformer. Most all modern units use electronic contactors to rapidly turn on-off and control the heat of the arc. When the contactor is not energized and the points open, the torch is safe with no power applied.
Reply:It's like the starter solenoid on your car. When you turn the key, the starter gets power to turn over the engine. As soon as you let go, the starter stops..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Ah! So, my POS 90 amp mig rig, with the tip always 'hot', is always 'hot' because it has no Contactor.This is primarily a safety feature, and secondarily, a heat/temp/current regulator, yes?I assume that the regulator function requires a large solid state device capable of high frequency operation. Thank you very much for the info.-andy-