Re: (ET) E-15 not getting out of first speed

[Kim Petty <kim coveside net>]

Mike, You sent me a picture of your main disconnect switch with a melted 
plastic terminal insulation .This indicates too much resistance in the 
switch. It could be the contact area or the terminal connections. If you 
don't want buy a new one ,I think you will have to remove the old switch 
and clean to bright shiny metal all parts including the threads and nuts 
on the studs. I don't think just tightening the nuts at this point is 
really going to do the trick. What do others think about the main switch 
being the 1st problem to tackle here? 
Kimball 

Sent from my iPad

> On May 22, 2017, at 9:16 AM, Larry Chace <RLC1 etnainstruments com> 
> wrote:
> 
> Hi, again, Mike.  The various models of tractor use various means to 
> control the acceleration.  Your E15 uses time delays to control the 
> speed advance from electric speed #1 to #2 to #3 to Field Weakening; 
> each delay is about 2 seconds.
> 
> The E12 uses a centrifugal switch to make sure the motor is turning fast 
> enough before switching from speed #2 to speed #3 (the higher speed for 
> an E12).  Other permanent magnet motored tractors also use this 
> technique.
> 
> Early E20s use some transistors and diodes to check the motor voltage 
> before allowing Field Weakening, thereby disabling electric speeds 6, 7, 
> and 8 if the motor is working hard.
> 
> Later E20s (and my I-5) use a relay to sense the motor voltage and 
> thereby control the use of electric speeds 3 through 7.
> 
> So, for your situation, the other tractor models aren't relevant even if 
> they have exhibited similar problems.  (Though it is really difficult to 
> imagine *what* could be causing the problems you've seen...)
> 
> GE was experimenting, you might say!  Also, the foot pedal controlled 
> E20 and I-5 perhaps didn't need as much automatic control as did the 
> hand operated speed controls.  I use both types of controls and each has 
> its own advantage.
> 
> I've found it useful to have an extra toggle switch that disables the 
> higher field weakening speeds.  On the E15, that switch permits the 
> electric speeds 5, 6, and 7, so when I push the hand throttle full 
> forward, I get electric speed 4 (one stage of field weakening); that's 
> just a small increase over speed 3.  On the I-5, the switch permits the 
> use of speeds 4, 5, 6, and 7 (all of the field weakening speeds).  That 
> lets me just floor the pedal while remaining in speed 3; that is similar 
> to the "cruise control" but isn't locked in, so I can lift my foot to 
> slow down or stop.  Another small modification provides for dynamic 
> braking by keeping the field energized (from the shorted armature acting 
> as a generator!) until the tractor stops (which happens rather 
> suddenly!).
> 
> Too much blathering -- sorry!
> 
> Larry Chace, Ithaca, NY  I-5 and E15
> 
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