Welder not charging battery
Most engine driven welders have the charge armature located underneath the flywheel of the engine, but you need to check a couple of other things before you start tearing down the engine. Look for a small rectangular module on the blower housing of the engine, on a Kohler this is at the side, on an Onan it's at the top. This is the rectifier/charger module and it will have 3 wires, the 2 on the outside will be the AC from the armature, and the middle one is the battery charge positive. With the engine not running, use a DC voltmeter to measure the voltage between this middle tab and the engine block, you should see a voltage that's very nearly equal to the battery voltage. If you don't see a voltage there you may have either a blown fuse, a tripped circuit breaker, or a broken wire leading to the battery. On some welders the fuse or circut breaker is inside the welder cabinet on the bulkhead between the engine and the generator parts of the welder.
If you did see battery voltage at the charge terminal, start the engine, switch the voltmeter to measure AC voltage and measaure the voltage from one of the outside terminals to the other, you should see 15 volts or more (be careful not to short out anything). If you get a nice AC voltage, switch back to DC and measure the charge output again (engine block to middle tab), it should be greater than the battery voltage we measured before and it should be slowly getting greater, if not the rectifier/charger module is bad.
If you didn't see enough AC going into the module, stop the engine, disconnect the plug from the module and use an ohm meter to measure the resistance between the 2 outside wires that go back to the engine, something between 100 and 1500 ohms is good. If you measure an open circiut (OL on my meter) or if you measure 0 ohms, the armature is probably bad. You have to take the flywheel off the engine to see the armature. If you got a good restance reading but the voltage is still low you may have one or more broken magnets inside the flywheel, again you have to do some serious disassembly to see if that's the case.
Nov 14, 2008 |