(ET) E15 motor problems.

[Christopher Zach <cz alembic crystel com>]

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