My Hobart 250 airforce doesn't start
My Hobart 250 airforce after 2 years of good service stop working. When I turn it on it starts for a split second and then the yellow light go on and fade away as there wasn't power and the equipment go dead. I've checked the power supply inside the equipment , the continuity on the wires that go to the torch, the continuity on the temp sensor at the torch and at both switches on the torch and the power switch. Tanks for your time on this matter.
Welding Tools - Miller - Hobart AirForce 250A Plasma Cutter w/Builtin Air Compressor
Answers & Comments
On the main circuit board for the power supply, there is usually a thermal fuse installed, its a sealed unit and is not servicible, look for a black epoxied case,approx 3/8x3/4 long, with 2 leads coming out of it. Inside is a set of bi-metal contact points which serves as an over voltage/over current protection. These contacts deform/corode over time and it sounds like there not contacting properly. As soon as you try to load the machine, the current passing through this high resistance heats these contacts up, and shuts off power to the unit. I am not familiar with the guts of a hypertherm, but have extensive experiance repairing inverter based plasma cutting equipment, and i have encountered this before. I assume hypertherm must have some equivelent to this thermal switch inside the power supply.....Good luck..