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Re: (ET) Most insane ground fault ever...
That is strange. I guess the first thing I would do is, with batteries
disconnected, measure ohms from main and lift motors wiring to frame to
see if anything truly has a short and then narrow it down from there. If
the main motor field has a short, it is not a big job to pull it and
tear it down. You may just have a rubbing wire or something else simple.
I have never opened a lift motor, but others have - it's not too bad
to get to either.
Frame shorts make for some very interesting problems. Let us know what
Chris Zach wrote:
This is going to go down in history as the most insane grund fault ever...
E20-AA type tractor. For purposes of this discussion, the headlight
wires are disconnected.
Here's the symptoms:
If I unplug the common wire to battery from the lift, the tractor works.
However if I toggle the lift switch up or down, the field weakening
relay closes with a *click*
If I plug in the lift to the midpoint of the pack (18 volts), the lift
will go up and down. However the tractor is pulling current thru that
wire to power the tractor field with 18 volts and the cc relay with 18
volts (not enough to pull it in).
If I move the lift wire towards the + terminals, the lift gets weaker.
However the current draw increases, and at around 30 volts the field
weakening relay closes with a *click*. At 36 volts there is no lift,
relay closes, full field on tractor motor.
If I move the wire towards the battery - terminal, the lift gets way
stronger fast. I don't want to go that way too far, as the lift will
All of the above only happens when the motor field is connected. For a
bonus, the drawing of current happens even when the tractor's main
disconnect is *OFF*
What the HECK is happening?
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