Tach testing

[mack]

Could be

I'm going to clean up the motor side and look very closely at the rotor. There are some filings in there too but for the most part it looks good. I'll check to see if I can find any scores or abraded locations on the rotor itself.

[mack]

Coil

So after cleaning up in there, I found the offending area. It's on the narrow inside sleeve of the rotor which the bolt goes through. Looks like when the coil windings fried the inside lip of the coil wobbled and caused the abrasions. The larger circumfrence of the rotor looks good. The red was from burnt copper, not rust. It blew out with an air gun but lunch won't be tasting too good.

[motoman]

So after cleaning up in there, I found the offending area. It's on the narrow inside sleeve of the rotor which the bolt goes through. Looks like when the coil windings fried the inside lip of the coil wobbled and caused the abrasions. The larger circumfrence of the rotor looks good. The red was from burnt copper, not rust. It blew out with an air gun but lunch won't be tasting too good.

Glad you chose to remove the alt. cover and found the culprit. That would of just got uglier in there with use....