Re: (ET) Armature Maintenance

["Konstanty, Walter (GE Energy Services)" <Walter Konstanty ge com>]

  Normal armature maintenance for a shop would be to steam clean and
bake above 300F for 4-6 hours to drive moisture out.  The problem with
brake cleaner or degreasers are that it can wash down contamination into
places you can't clean further or remove it.
  For us normal guys, a good clean air gun (done outdoors) to blow out
carbon is usually good enough.  Carbon will vacuum/blow out unless oil
is on the armature to make it sticky.  
  An air dry varnish would help "seal" the windings which were
originally enamel coated magnet wire.  You can get that at Graingers or
GEXPro industrial centers but make sure the windings are clean and not
grounded.
  The commutator can be sanded lightly but blow it out real good to
prevent loose copper particles from imbedding into the brushes which can
be a problem.  Clean the end of the commutator to prevent tracking to
ground.
  Blow the stator out and always install new bearings.... the motor can
be test run by wiring it to the tractor or even applying 12 volts to the
armature and field for bench testing.  Listen for abnormal clicking of
the brushes or bearings.
 
....Walt
    (supposed to be a motor expert)

-----Original Message-----
From: David Roden [mailto:etpost drmm net] 
Sent: Sunday, July 10, 2011 11:28 PM
To: Elec-trak cosmos phy tufts edu
Subject: Re: (ET) Armature Maintenance

On 9 Jul 2011 at 20:49, Karl Halbert wrote:

> 1. I have some wires that are nicked (shellac gone) but not cut all 
> the way through, what is the best way to seal them up again.

I'm far from being a motor expert, but since nobody else seems to have
tackled this, I'll have a go at it.  If I'm off base, someone please
correct me.

I think the stuff they coat windings with in electronics (such as small
transformers) is similar, and it's a baked shellac.  You might be able
to do it at home.  However, if you have a significant other who likes to
use the oven for baking, you might get some static.  ;-)

But come to that, the wire used to wind armatures and transformers is, I
think, coated in some kind of enamel.  A little research along those
lines might be in order.

> 
> 2. I have an armature that can from a rust bucket motor housing and i 
> covered in rust dust and stuff... what is the best way to clean it I 
> know I do not want to use chemicals that will cut the shellac
(alcohol)... WD40?

A longtime electric vehicle hacker once suggested automotive brake
cleaner to get the gunk out of my Comuta-Car's motor.  It seemed to work
well.  Just be sure to follow the cautions on the label - it's rather
nasty stuff.

If in doubt on either point, I suggest engaging a reputable motor shop
instead.  These motors are scarce enough and pricey enough that it's not
worth risking them, IMO.  Call your local golf course and ask them who
services their golf car motors (assuming they're electric golf cars).


David Roden - Akron, Ohio, USA

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