50's welder/generator

[The_Supernerd]

I found a welder from the early 50's that is suppose to be military surplus. It can weld 400 amps DC and has a Chrysler industrial inline 6 flathead engine. It will only weld at 400 amps, none of the lower settings work. Would this most likely be an easy fix or does it sound like it could be complicated? Will I be able to find parts for it? I do not have experience fixing welders, but I have some basic knowledge of electronics. Thanks in advance.

[Phillip Hutchinson]

G'Day
If it has a rotary type of rheostat the wiper arm may be at fault,but as to why it runs flat strap is a bit of a mystery.I have repaired these type of welders in the past (very distant i might add).just thinking about it i think a D.C welding generator has the armature in series with the armature and uses the rheostat to control a set of shunt coils (in parrallel with the armature) to control it,hense goes flat out with no control
I think your kowledge of electonics would be waststed on this piece of machinery.I'm not saying that i am right but its a bit hard to tell whats wrong with it from the other side of the planet,hope this is of some help.
Regards Phillip

[Andrew Mackey]

There should be 2 sets of controls - one for voltage (fine tune), and one for current. Eirher the resister that controls current is not turning to a lower setting, or there is eiyjer a short, or dead open wire within this section. On an old Lincoln welder I had, the resisters were coil wound0on ceramic, units. The ceramics had broken, leaving an open circut. Replacements were expensive, at the time - $275 just for the fine tune resister I didn't wait to find out what they wanted for the other one!
Andrew

[The_Supernerd]

Thanks for the advice. I will look at it closer before I decide to buy it.