Sparking comutator
Sparking comutator
(OP)
Ive got two quite old but decent quality small angle grinders here(one Metabo, one Bosch)that I have put new brushes in but are both sparking quite violently at the comutator. Its actually several years ago that I put the brushes in so I can't exactly remember the history but I think the Metabo stopped because the wear springs popped out and I replaced those with correct brushes I had in stock. I think I then checked the Bosch to find that they too were worn and put some in that had come as spares with a "far eastern" grinder, they fit well in the carrier and the joining wires are soldered. I have susequently turned the Bosch comutator on a lathe which has made no difference. Any advice on action or things to check would much appreciated as it would be a shame to throw them away if its something simple. Thanks.





RE: Sparking comutator
Turning them on a lathe is not always commendable if you do not have the right tool (small angle) and run at a very high speed.
After turning, you have to remove the mica (could also be plastic) between the commutator bars. And grade the bar edges. But that is not something one does with these small machines. They are use and scrap items.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Sparking comutator
Muthu
www.edison.co.in
RE: Sparking comutator
Very often worn out brushes and a damaged commutator go hand in hand.
I agree with Gunnars advice also.
How to tell if the sparking is excessive? Poor performance is one indicator. Use the tool, if the sparking is really excessive, the armature will soon fail completely and remove all doubt.
Bill
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"Why not the best?"
Jimmy Carter
RE: Sparking comutator