Boxford TCL , Spindle motor problem

[John11668]

John you may find that the worn brush and loose connection has sent spikes back to the controller over a period of time and stressed some components on driver board. Knocking may have been the instantaneous changes in speed. It also may have damaged some segments of the commutator or has carbon shorting out in slots. You can clean segments out with a groundown back of hacksaw blade and run along slots to remove carbon. If commutator worn you can lathe down commutator and scrape out the insulation to below segments using sharp end of hacksaw blade as mentioned above---old trick used in automotive industry before throw away society became the norm. Can you check if commutator still arcing with new brushes by leaving the cover off to test. You may be able to reach in and clean slots without disassembling motor.

I have done all of this johnny ( Just had motor apart a second time to re-bed brushes again this time with 320 grade paper and now running in again)
Makers tech rep suggested that I run the motor with a current limit of half capacity (set about 2 amps ) and use the belts to gear down. I tried this now normal running is at about 0.8 amps, 100 volts max at 9.7v dc input, but it still stalled on screwcutting. No signs of any motor problems , no arcing at the com , . Motor runs sweet just no torque boost when needed.
And as I have said before it was fine initially and handled all the loads I was going to put on it . Frustrating!

[John11668]

I ran the motor today on a separate 42v power supply and of course it would only run at about 500 revs but at that I could take a millimeter off diameter in a single cut without stalling. So the motor seems to have the guts for the job.. Speed drops a tad and current goes up but the torque is there despite low voltage.
I reckon the drive has fallen over . Now waiting to hear what suppliers will do about it .
Drive is supposed to be self protecting so should look after itself if a brush wears out (you would think anyway)