"Martik" wrote in message
news:Hj3Id.133368$KO5.1002@clgrps13...

"James Sweet" wrote in message
news:zy%Hd.13338$Os6.4292@trnddc08...

"Martik" wrote in message
news:jeIHd.36644$06.34415@clgrps12...
Posted here a while ago broken speed control: Well they sent me a
new
one - no charge! but the damn thing still won't work. The motor just
hums
in
all positions of the control. I measured 100VDC going to 2 of the 4
wires
to
the motor. The motor bearings and brushes look good. Any ideas what
further
diagnosis I could pursue?



There's 4 wires to the motor? I had assumed the brushes would be in
series
with the field coil, you need voltage to both pairs of wires for the
motor
to run.

The 2 wires to the brushes have the 100VDC, I do not know what the others
are for.

Here is a picture, the red and blue wires go to the brushes:

http://www3.telus.net/martik/motor.jpg



Can't really see much there, that's definitly the commutator of a universal
motor though. As I said before, you need power to the stator windings for
the motor to run, otherwise you'll just burn up the armature.