What are the annular grooves in this motor's commutator?

[mjhoshaw]

I've seen other images of Ametek motors that have them.  What purpose do they serve? It's hard to tell how deep they are. I have to think they would make the brushes wear unevenly.


 


Clearly they're there for a reason, but I have no idea why. We have so much combined knowledge here that someone must know. Thanks.


 


Joel

 

[mjhoshaw]

A question on top of a question

I'm adding this to the thread because both questions have to do with motor design and construction.


 


I know there are exceptions, but it seems like most vacuum motors today have double ball bearings. Is that because they run at such high speeds compared to yesterday's motors, and a sleeve bearing wouldn't last?


 


Joel

 

[madman]

I don't know for sure but I'll bet you the commutator is perfectly flat and normal. It's the brushes that have grooves in them and a motor with very very few hours on it would pick up the marks of the brushes' grooves before wearing them down enough to get past the grooves. I'll bet the grooves in the brushes are very shallow, perhaps to quicken a break-in period.

 

[mjhoshaw]

Thanks, I hadn't thought of that

It makes sense though. Under high magnification it appears the brushes indeed are grooved. I appreciate your reply.


 


Joel