WWII airplane generator

Charlie

Eons ago, my dad did that. There's multiple problems as a welder. First the generator is driven through a quill shaft so the engine speed can be varying while the generator speed isn't. Its a spring. That prevents belt drive without an outboard bearing or two. That quill shaft breaks under heavy welding and is hard to replace. E.g. the spares aren't on the shelf.

The generator is shunt wound with interpoles to make it have good voltage regulation. That's the last thing you want for welding. In welding you want current regulation. When you try to turn down the fire by introducing resistance into the field circuit you loose open circuit voltage and its hard to get an arc started.

My dad drove his from a model B Ford engine. First from the flywheel end and then when the quill shaft broke, from the crankshaft pulley end with the stub of the quill shaft stuck into the generator backwards. He wound a large choke to give the arc some stability, it had a core made of a roll of #9 fence wire rerolled into a torus about a foot in diameter with a single layer of about #4 insulated wire through the torus. The core had a round cross section about 3" diameter.

He rigged up a solenoid to open the throttle on the engine in response to a button on the electrode holder so he didn't have to run the engine fast except when actually welding.

It was good for welding currents way over 100 amps, 100 to 250 amps. Wouldn't work below 100 amps, so light work, like water pipe tended to have more holes after welding than before. With 1/4" and thicker stock, though, the welds came out fine.

My dad has been much happier with his Lincoln 125 amp arc welder. Far more compact, immensely quieter, and much easier to weld with.

As for alternative energy uses, the aircraft generator was made for lightness while attached to a several hundred HP engine. There are several models, some are made to work only at high speeds like 4,000 to 8,000 RPM. Energy efficiency was not a major concern. Probably the more modern automobile or truck alternator does everything better but will handle the same range of speeds but work fine a lower speed.

Gerald J.

15 or 20 years ago I picked up a repair kit for one model that had a manual and spares.

For me wiring is easy, but I'm an electrical engineer. The connect up similar to a car generator, just more voltage and current.

Thing about a DC generator is that with the field voltage held constant, the voltage is directly proportional to the shaft speed. So if you wanted 14 volts you could turn it slower than the military rated minimum speed.

Some have ratings on the nameplates. Sometimes Burden's Surplus Center in Lincoln has data in their catalog. Might be some other places with them that have information. Aircraft shop manuals like for the WW2 B24 will have data.

Gerald J.