Re: (ET) uh-oh what'd I do now...

[dave barden <daveb speakeasy org>]

Yesterday I got back to the E-trac and sure enough the reversing relay had
one set of burned points.  I couldn't get my ignition file between them so
clean them up best I could with sandpaper.  There was a 25amp fuse that
blown as well.  After replacing it and putting the relay back in I held my
breath and applied the power with the trans in neutral and heard the motor
turning normally both in forward and reverse.  Hot damn it runs again.

Thank you all who responded with probable causes and suggestions .  I 
really
appreciate and admire your knowledge and willingness to share it so freely.
Someday I hope to be able to do likewise.

BTW the relay I am using came from the Hosfelt catalog.  I have the $20
version from Bill G sitting on the shelf as a spare.  A friend of mine 
found
this relay that is pretty close (32v rated) for $1.49!  Now I'm glad I 
fried
that one and not the $20 one.  I really don't know maybe I got what I paid
for??  If anyone is interested in these inexpensive relays I'll dig up the
catalog and post the ordering info.

Yet another question.  Does the fact that my relay took a big hit point to 
a
bad varistor??  I understand the varistor is supposed to protect, soak up,
surges but that they do deteriorate with age.  I have a brand new one but
haven't put it in because it looked like a messy job (buried in amongst a
mess of wires).

thanks again, this is a great group and resource,

dave barden


"David Roden (Akron OH USA)" wrote:

> Changing direction before the motor comes to a stop can weld or burn the
> contacts on the reversing relay (which on my tractor reverses the
> polarity on the field, not the armature).  That would fit with your
> statement that the tractor now wants to go backwards -- the motor's only
> field now comes from a bit of residual magnetism, and that's the last
> direction it ran.
>
> Don't try to run it this way, or you'll damage the commutator and/or
> armature.  Visual inspection may reveal the problem.  The relay is
> located on the back of the vertical panel in the rear of the front
> battery compartment (at least it is on my E-15).
>
> To confirm or test, disconnect one of the armature terminals.  Then with
> the rear wheels off the ground and trans in neutral (for safety), apply
> motor power and measure voltage across the field at the motor.  If it's
> zero, that's probably the problem.  New reversing relays are available
> from Bill Gunn.
>
> David Roden - Akron, Ohio, USA
> 1991 Solectria Force 144vac
> 1991 Ford Escort Green/EV 128vdc
> 1979 General Engines ElectroPed 24vdc
> 1974 Honda Civic EV 96vdc
> 1970 GE Elec-trak E15 36vdc
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