[Robaroni]

Originally Posted by dh1

Most GE Elec-Trak drive motors are Separately excited, some are PM type.
This is the Alltrax controller that is recommended for the Elec-Trak with SepEx motors.

Electronic Controller - $418.00 : The Electric Tractor Store :: Elec-Trak Parts

With the manual and Wiring diagram.
I am currently doing a Alltrax conversion on an E15 tractor.

Doug,
Doesn't matter.

Why throw out the 'baby with the bath water?' Let's say we use a microcontroller to 'dry' switch the motor direction using the relay from the ET, which should last indefinitely dry switching it. All we need to do then is PWM the field or armature with the same uC using a quadrature encoder as the throttle. The uC does all the work and programming it is what I do. The simplicity of the design goes way down.
I'm planning on building a couple of these for 50 to 75 bucks tops, if there's enough interest I may see about selling boards and programmed chips.

Rob