Re: (ET) Brush issue...

["RJ Kanary" <rjkanary nauticom net>]

If there is no obvious burning, or discoloration of the bars, a light
polishing is the most that I would do. Do not use emory cloth, due to the
fact that the abrasive is conductive, and has the potential to cause
problems. This I have never been able to verify, since I have never used 
it.
   Any well equipped starter/ alternator shop would be able to assess, and
address, and major concerns, such as truing up the commutator, and
undercutting the mica, if needed. If an armature  does need 'turned', be
prepared for a comment from the technician about how hard the material the
segments are made of is. GE did not cut corners on the motor construction.
They are simple, and built to last.



RJ Kanary
Member TRNi  Since 1998
ASE® Certified Master Auto Technician

rjkanary nauticom net

----- Original Message -----
From: "Tom Coate" <tcoate coate org>
To: <elec-trak cosmos phy tufts edu>
Sent: Wednesday, May 29, 2002 9:41 AM
Subject: Re: (ET) Brush issue...


> Taking this off on a slight tangent...  Is there a preferred approach to
> cleaning the commutator bars when inspecting or replacing brushes?  Or is
> it best to just let them be, especially if the motor has been seeming to
> run OK?
>
> At 09:37 PM 5/28/2002 -0400, RJ Kanary wrote:
> >That can be a concern, as the brushes get shorter.As the brush shortens,
the
> >spring tension that keeps it against the commutator is reduced. This, in
> >conjunction with the shorter brush more readily transferring heat to the
> >brush holder, makes sticking a possibility. Add to this, increased
armature
> >run out, caused by fair wear & tear, of both the commutator bars, and 
> >the
> >armature bearings, and the recipe is complete. This input was gleaned 
> >for
my
> >Dad's many years of maintaining DC operated overhead cranes, and small
> >Diesel / Electric switch engines.
> >
> >
> >RJ Kanary
>
>