Motor Brushes and Cush Drives

[thamesmud]

Just looking at some motors I bought second hand and pulled the brushes to see what condition they were in.

I'm assuming the corrugated surface finish is put on from new to help the brush bed in, in which case I appear to have motors that have NOT been given the "BM" treatment
On big motors I know it's standard practice to bed in brushes to the diameter of the commutator to reduce commutator pitting and arcing. I wonder, Is fitting the brushes like this another way the manufacturers screw us over and reduce the lifetime of motors ? I cant believe they consider motors and gearboxes to be "non serviceable items" and don't supply at least the motors as spares.
I'm going to be sleeving the cush drives, I've got plenty of tube, does anyone else need some sleeves while I'm at it ?

[ICEUK]

Hk Thames,

I wouldnt mind some sleeving, I have a pair or linx motors that i intend to replace brushes as thry have done 2.5 miles. I just them as spare.

[rover220]

Just looking at some motors I bought second hand and pulled the brushes to see what condition they were in.

brush.jpeg

commutator.jpeg

I'm assuming the corrugated surface finish is put on from new to help the brush bed in, in which case I appear to have motors that have NOT been given the "BM" treatment
On big motors I know it's standard practice to bed in brushes to the diameter of the commutator to reduce commutator pitting and arcing. I wonder, Is fitting the brushes like this another way the manufacturers screw us over and reduce the lifetime of motors ? I cant believe they consider motors and gearboxes to be "non serviceable items" and don't supply at least the motors as spares.
I'm going to be sleeving the cush drives, I've got plenty of tube, does anyone else need some sleeves while I'm at it ?

The motors are supplied as spares by every manufacturer I've worked with.

[thamesmud]

The motors are supplied as spares by every manufacturer I've worked with.

That's good to know. I suspect I had to have the motor and gearbox due to the change from the 2 bolt AMT to the 4 bolt Linix.
Just an aside for anyone else converting from AMT to Linix. The Linix motor mounts (gearboxes) are bolt compatible with the AMT but the Linix gearbox is 5mm wider. On a "special" the Linix motors may foul on the battery box needing the brackets re-drilling.

[Burgerman]

I think rover means complete.

[owenminor]

Woah, nelly. Memories.
RC car racing involved a lot of blackmagic/voodoo on brushed motor break-in. Communicator lathes. Brush cutters. Breaking in the motor in distilled water. Brasso and oil to break in the bushings.

But ignore all that. The root idea is: Get the brushes to a perfect radius that matches the communicator, using as little voltage/current as possible, so arcing doesn't pit up the surfaces you're trying to mate.

My thought is that, probably, the easiest way to get that would be to plug the motors in before mounting them and tape the stick in place at a very slow speed forward. Let it run for 30 minutes, without interruption or messing with the stick. Every start/stop will cause more arcing.

Those serrations are quite definitely for reducing break in time. But not good for high load until they are worn away.

[rover220]

I think rover means complete.

Indeed.

I don't think any of the manufacturers sell gearbox seperate. Some will sell brushes as spares.