Re: (ET) E-20 rebuild report

["Christopher Zach" <czach computer org>]

Took apart the motor again and cleaned out the brushes. Used electronics
cleaner (leaves no residue) on the brushes and the housing. All back
together and now running. The motor is smooth turning by hand, no grumbling
or play in the shaft.

The core problem with the motor was the sticking brushes however. I wonder
what caused the brushes to stick; was it a bad design, or something 
happened
in the field (maybe the blade hit a rock or something, but that wouldn't
explan a slightly off-square brush housing.)

Chris


----- Original Message -----
From: "David Roden (Akron OH USA)" <roden ald net>
To: <elec-trak cosmos phy tufts edu>
Sent: Sunday, January 27, 2002 12:51 AM
Subject: Re: (ET) E-20 rebuild report


> On 27 Jan 2002 at 0:37, Christopher Zach wrote:
>
> > Are these brushes a common-stock item, or are they not
> > manufactured anymore? Any particular places to get them (along with the
> > temp sensor)?
>
> Bill Gunn should be able to supply all these parts.  I recommend ordering
> a "homeowner's service manual" at the same time.  It has an excellent
> section on troubleshooting with flowcharts.
>
> I mostly trade with Bill now, instead of searching for equivalents
> locally, so as to keep him in business and supporting the ET.
>
> >
> > I'll remove it tomorrow. Can one use rubbing alcohol on the brushes and
> > housings to clean things off?
>
> Don't know -- never had to do it.  Note that rubbing alcohol may also
> contain non-solvent ingredients which can leave a residue.  I would use
> denatured alcohol from the drugstore, or shellac thinner from a paint
> store.
>
> >  It's also possible I don't
> > know the sound of a good motor. What do they sound like when running?
>
> Hard to describe, until you've heard worn bearings and good ones.
>
> It's easier to gauge the bearing condition by feel.  Unplug the deck and
> turn the mower blade by hand.  It should feel smooth, not rough, as it
> turns.  Give it a spin; it should coast a bit, and should also cause the
> other blades to spin up a little, since the motor is acting as a
> generator.  There should be very little noise at that speed.  If you hear
> a metallic sound, the bearings are definitely going.
>
> >
> > > Be sure to tell Bill or the repair shop that you put oil on the
brushes.
> >
> > That big of a disaster?
>
> Just so they know that the brushes and brush holders need to be cleaned
> or perhaps replaced.
>
>
> 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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