DC motor brush failure
DC motor brush failure
(OP)
Hello,
I have a small DC motor that is burning up the Negative brush. See photo.
Anyone seen this before?
Any ideas what could cause this?
The motor is used by me in many linear stages, but only fails in one. The one that fails is unique only in that is has a faster lead screw. It operates at about 1/10 of it's rated peak current.
Thanks.
I have a small DC motor that is burning up the Negative brush. See photo.
Anyone seen this before?
Any ideas what could cause this?
The motor is used by me in many linear stages, but only fails in one. The one that fails is unique only in that is has a faster lead screw. It operates at about 1/10 of it's rated peak current.
Thanks.





RE: DC motor brush failure
What is the supply? Battery, Rectified, well filtered AC. Rectified poorly filtered AC, PWM drive?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: DC motor brush failure
What is the lead screw actually doing? is it lifting something?
RE: DC motor brush failure
Yes, in this case the lead screw is lifting a mass.
RE: DC motor brush failure
Well if you provide details of what its lifting and rotation speed + pitch of thread it might provide some clues to the failure, also if you provide duty cycles of the other loading conditions which don't cause it to fail that also might help, finally what is PWM driven.
RE: DC motor brush failure
Does the lead screw present unrestrained end thrust?
How does the commutator look? The supposedly good brush doesn't look very good.
Are you able to put an oscilloscope on the output of the drive?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: DC motor brush failure
RE: DC motor brush failure
RE: DC motor brush failure
Thanks for this paper. I believe it a brush type problem, where the film is too thin. This paper explains the phenomena very well, and gives me some things to try.
Thanks again!