Re: (ET) Ideas please - E15 reverse only

["David Roden" <etpost drmm net>]

I wonder whether the long power-on period might be a red herring here.

Sidebar: I did the same thing once or twice, so I added an off-seat 
Sonalert.  It yells at me if I get off the tractor without turning off the 
key.  It's annoying, but it keeps me from being careless.

Anyway, the reverse design on the E15's GE controller is straightforward 
and *should* be reliable.  It's a DPDT relay that reverses polarity to the 
motor's shunt field.  It's often NOT reliable.  I'm not an electrical 
engineer, but I think that GE both undersized the relay and failed to 
provide enough (reliable) surge suppression for the inductive kick that 
its 
contacts have to handle.  

In my limited experience the best long-term fix is to junk the GE 
controller and fit a modern solid state controller to the tractor.

Before I did that, my usual reverse problem was that the ET wouldn't 
reverse when put in reverse. That can be disconcerting, to say the least. 
The final straw was plowing the driveway with the hood up and the relay 
panel tilted down, reversing the tractor by pushing on the relay flapper.

I haven't had the GE controller in mine for many years and am going from 
memory here.  If I make an error below I hope that others will correct me.

For the E15 to *stay* in reverse, the relay contacts would have to have 
welded or stuck, or the circuit powering the relay coil to have somehow 
closed and stayed closed.

I can't recall now when the microswitch on the speed lever engages the 
reverse relay.  You'd think it wouldn't pull in the relay until it's 
actually in a reverse position, but a little mouse is whispering that 
maybe 
it does so in stopped position. Somebody help me out here, please.

If you haven't yet inspected and tested the reverse relay that's the place 
to start.  It's mounted to the black metal panel below where the hood 
opens.  Unscrew the panel and tilt it out.  You may be able to see that 
the 
relay contacts are in the down position. Otherwise break out the 
multimeter 
and check contact continuity (wires disconnected).  Power up the tractor 
and check for voltage across the relay coil.  If the relay clicks when you 
turn on the key and the speed lever is in forward (trans in neutral!), 
check for a stuck reverse microswitch on the speed lever.

Voltage tests are better done with an analog voltmeter as the very high 
input impedance of a DMM will fool you with "phantom voltage."  Or you can 
put a resistor of around 47k ohms across the DMM's test leads.  The value 
isn't critical, 27k, 33k, 68k, or 82k is probably OK too.

Good luck!  Please let us know what you find.


David Roden - Akron, Ohio, USA

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