I agree with George - there are issues with that motor. I would guess bearings - especially if they are the cheap Chinese ones. Cooling off the outside of the motor will not solve a bad bearing problem nor will it solve an internal motor wiring problem.
Since you also have problems with the spindle overheating, I would undo the mods to the motor and send the whole machine back. You are just asking for trouble down the road if you continue to run it the way it is.
Greg
Since you also have problems with the spindle overheating, I would undo the mods to the motor and send the whole machine back. You are just asking for trouble down the road if you continue to run it the way it is.
Greg