In a message dated 5/8/2013 11:43:10 AM Mountain Standard Time,
[email protected] writes:
> Subj:Re: [EVDL] Weird Rear Brush Sparking
> Date:5/8/2013 11:43:10 AM Mountain Standard Time
> From:[email protected]
> Reply-to:[email protected]
> To:[email protected], [email protected]
> Received from Internet:
>
>
>
> The rear brushes of a dual set will wear down faster than the front
> brushes.
> The rear brushes may shunt the front brushes thus more current flow
> through
> them.
>
> My first motor was a GE-11 that was blue printed by a GE company in
> Michigan. They v-groove the communtator just enough to take off the
> communtators bars sharp edges. Then they micro mirror the surface to a
> mirror surface.
>
> This motor was ran from 1976 to 2000 before pulling it out for
> maintenance.
> The rear brushes were half the length of the front brushes. This shorten
> length will cause lower spring tension then the front brushes.
>
> I use a WarP 11 spare motor while I have the GE-11 motor in maintenance.
> I
> first run the WarP 11 motor non blue printed on a motor test stand to
> check
> the running action. The communtator bars had very rough edges and surfaces
>
> where you can cut yourself.
>
> Run the motor to see what the brush action was, and as I suspected, there
> was a lot of brush chatter which started to chip the edge of the brushes.
> I
> than remove the rotor and V-groove the communtator bars with a V-file and
> than micro mirror the communtator on a lathe using a fine crocus cloth.
>
> Before installing this type of motor in a EV, it is recommended to take
> and
> record the ohm value throw the rotor circuit, rotor to motor frame, field
> circuit and field to motor frame.
>
> Normally a brush type motor should read over 20 meg/ohms to the motor
> frame.
> In about 10 years this reading could be reduce to 50 K/ohms where it is
> recommended for maintenance.
>
> The problem with a brush motor is that the brush dust tracks from the face
>
> of the communtator down on to the motor shaft which causes a current leak
> to
> the frame of the vehicle. This is why some people has read a voltage on
> the
> frame of there EV even if the batteries are in a isolated non-conductor
> battery box.
>
> Roland
>
Good post here Roland.I have in the past(my dragster and S10)removed some
shunt lead from the inside(rear) brush because of the above.I wanted ALL the
brushes to Share equally.Also check the spring pressure.
Dennis Berube
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20130508/75a5679c/attachment.htm>
_______________________________________________
UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
http://lists.evdl.org/listinfo.cgi/ev-evdl.org
For EV drag racing discussion, please use NEDRA
(http://groups.yahoo.com/group/NEDRA)
