Well, my rusty E15 has started having issues recently. Specifically
the motor power would drop, then come back. Intermittent, and was
not a problem with the contactors since the armature and field
voltages were both a nice solid value.
So the motor came off. Getting the end off is tricky; you have to
tighten and loosen the screws bit by bit before they come off. But
use the exact right screwdriver, and it will work.
With the motor end off I saw the problem; one of the brush wire
forks had broken off the motor stud and as a result the motor would
run with high resistance from time to time. Also the plastic shield
around the brushes was broken into bits, and the brushes were
getting small.
Since I didn't have spare brushes, I decided to swap them. I took
out the brush assembly, and put a new fork on the damaged brush
wire, then swapped the brushes. Then I cleaned out the whole end
bell, and vacuumed out the motor (what a mess of carbon).
With that done I took a look at the end bearing. It was sound, but
kind of stiff. I sprayed a bit of penetrating oil and rubbed in some
30 weight oil and the bearing went to nice and smooth. I should
replace it, but it seemed to just have dried up the oil in there,
now it's refreshed.
The E-145 motor is a pretty simple shunt-compound motor. The power
for the brushes goes through the brush, commutator, other brush, to
a compensating field, then to the other side. Only two brushes, I
thought it might have four; does the E20 motor have 4 brushes?
Then put the motor back together, put it in the E15, and it's
running fine. I'll order a set of new brushes a new shield, and a
new square spacer. Then I'll drop the motor again and refresh it.
Next up is to POR15 the seat deck and put the new seat on. I got the
old one off, but one bolt is still stuck on there. Maybe I'll burn
it off...
Chris
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