Brushes look Good ????

[bherr]

OK,
I finally got the motor pulled out far enough from the casting to really get a good look and discovered that the brushes look pretty good, I think. the second photos shows a lot of greease or oil on the brush connectors, so you think this could have been causing my spindle to shut down during cycle runs? I have pulled the Tacho to check those brushes yet, but curious on the photos attached. Need your opinions.

Thanks,
Ben

[Al_The_Man]

The brushes look a good length, you had mentioned in the other post that one had completely gone?
Grease is never good on brush gear, the grease becomes a carbon mixture and can be conductive to cause ground faults. As someone mentioned the Commutator looks worn, if you have gone this far it may pay to pull the armature and get the comm turned, some modern commutators do not need undercutting, the insulation between the slots wears with the copper, the older (and some current) motors used mica between the comm bars and this needs cutting down below the newly turned level. This can be done by hand with a hand made tool or there are electric ones available.
Al.

[bherr]

Originally Posted by Al_The_Man The brushes look a good length, you had mentioned in the other post that one had completely gone? Grease is never good on brush gear, the grease becomes a carbon mixture and can be conductive to cause ground faults. As someone mentioned the Commutator looks worn, if you have gone this far it may pay to pull the armature and get the comm turned, some modern commutators do not need undercutting, the insulation between the slots wears with the copper, the older (and some current) motors used mica between the comm bars and this needs cutting down below the newly turned level. This can be done by hand with a hand made tool or there are electric ones available. Al.

Thanks Al, the problem I was having was the spindle intermittenly shutting down in a cycle run. I wasn't looking in the right spot for the brushes, so they are all good, like in the picture. I do have replacement brushes for the Tacho, but haven't taken it off to inspect them yet. I think you and others are right, since I have the motor this far removed, I might as well take it all the way out and get the commentor milled down.

Ben