[major]

Hi Dunc,

Been hoping to view your photos on larger screen. But this tablet will do. Guess you're lucky not to have big damage in the motor from the sounds of it. I don't see anything obvious which would cause symptoms of shutting down or losing power as you described.

Comm looks a bit raw like high current/arcing has stripped the film. I'd definitely check out the comm for t.i.r. Needs to be 30 microns.

When you lost traction it may have oversped the motor causing a bar to lift. A high bar, or segment could damage/chip those brushes. I think you need the bar-to-bar deviation at 5 microns.

Replacement brushes/springs. Maybe forklift repair shops. Motor rebuilder.

If comm checks out or is serviced, I'd be tempted to install current brushes and do a lengthy break-in.

I found an excellent read on Mersen website.
https://www.mersen.com/publications?s=Commutator&p=63

Regards,

major

 

[major]

Hi Dunc,

Sorry for the delay. Lucky you found the same motor for replacement since you were pleased with its performance. From what I see in the photos, it looks good to go except for the brushes. BTW, break in for longer than an hour. Like maybe a week.

For extra insulation and "gluing", use Glyptal 1202. Factory likely used a polyester resin. Retreating an entire armature nothing beats vacuum impregnation.

You might be right about damage to the original armature but the arc flash event could have spread those laminations as well.

Good luck,


major

 

[major]

Hi Dunc,
I typically use emery cloth or even sandpaper, fine grit, for the contact buttons. Blow the dust out afterwards. Smooth to the touch and closing without any gaps should be good to go.
Regards,
major