Re: (ET) E-20 rebuild report

["David Roden (Akron OH USA)" <roden ald net>]

On 26 Jan 2002 at 14:34, Christopher Zach wrote:

> Lesson one was learned: When experimenting with something, always start
> out with nice, small batteries.

Wrong lesson!  Nice small batteries will ~also~ damage parts which are 
not intended to have batteries connected to them.

Right lesson #1:  RTFM.  (Read the friendly manual.)  

Right lesson #2: Examine closely before connecting anything, and test 
with an ohmmeter first.

Right lesson #3: Think before acting.

Right lesson #4: Never assume.

Right lesson #5: Email this list before taking things apart.

> put a dab of oil on the brush. 

Ouch.  I repeat, RTFM.  You do not put oil on brushes.  They get warm or 
hot. The oil will get gummy, and do unpleasant things.  You need to 
disassemble and clean all the oil off there.  I'm not sure whether oil 
contamination can be removed from carbon brushes -- you now may need to 
replace the brushes in addition to the temp sensor.

> Put a drop of oil on the bearing, reassembled the motor (tough to 
> get those washers in there right) and bolted it all down.

The bearings are supposed to be sealed and permanently lubricated.

> Put 12 volts across it, motor spun up. A trifle noisy; I am not 
> sure why, but it spins.

It's probably noisy because the bearings (or at least the lower one, the 
most common failure) is/are worn.  Operating with worn bearings can cause 
destruction of field magnets; this is very expensive to repair.  

Take the motor to a motor shop, and have the bearings pulled and 
replaced.  Or send it to Bill Gunn for rebuilding.  I don't recommend 
this procedure for someone not familiar with motor construction.  

Be sure to tell Bill or the repair shop that you put oil on the brushes.


David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1979 General Engines ElectroPed 24vdc
1970 GE Elec-trak E15 36vdc
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