Alternator Unable To Supply Power To Welding Machine

Maybe a flywheel will help?

Quit, and Get the job where a healthy alternator found.

What type of welding machine is it? Transformer, motor driven generator, spot welder, etc. What different type(s) of welding can it do? AC stick, DC stick, Dc reverse polarity, Mig, Tig, submerged, high frequency, spot welding, etc? It sounds like a transformer but is this correct?

The better and more complete the question is, the better the answer will be. List the things you think are important, list the things you think are maybe important and then list the things we might find helpful.

Is there a loose contact in the outlet for the welder on the alternator system? If the lathe and drilling machines work fine on the alternator circuit, the welder will not run on the alternator system, the welder will not work on the alternator circuit when it is the only tool connected, and the welder will work on the 3 phase system it sounds like the socket on the alternator supply to the welder is faulty and the socket for the 3 phase system is good. Take an volt meter and check the supply to the sockets and the voltage on the wire terminals of the welder plug and see if there is an open connection in the sockets or plug.

Good Luck, Old Salt

I would guess that a welder takes somewhere between 3-7 times its "running" current at weld start, due to it being an inductive load.

Like AC motors for example, though I must admit that I have never monitored that myself on a welder. The welder manufacturer might be able to supply more detail on this point. It may even be called "inrush" current, or at least that should be the name you can use when asking....its a good starting point!! There is maybe a better name....

But if true, does this exceed the maximum current that the generator can supply? Blowing a diode could be an indication of just that. Did you notice the diode characteristics and the type name? That could also indicate whether a lack of power is part of the problem or not!!

Post the type name here please?

You found a shorted diode,but did you check the other diodes?

I suspect you may have a diode that has failed in the open condition.

This would limit the current available without shutting the alternator down,as with the shorted diode.

There are normally 2 diodes per phase,so check them all.

Also check your welder (is it a DC welder?) for ampere draw,and open diodes,if it is a DC welder.

It could have an internal fault(diodes?) making it draw more current than can be supplied by the Alternator.

Remember, something made the original diode fail.