You're correct, the gauge shows it's charging once the squealing stops. I'll take a look at the exciter to learn more about it.
Thanks for the idea.
The squealing is from it slipping. If it was an field excited style it would not squeal as there would be no load at that time. Next time start it rev it up two or three times. Shut it off and feel the pulley for heat. If its hot its slipping. Tighten it some more and see what it does. I guarantee I could have it stopped in 5 minutes. The 304 is hard to get the belt tight.
