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Re: (ET) More lift motor thoughts
I think your rear is on the wrong taps. They should BOTH be run off "18V".
Getting the taps wrong is REAL common. Even though I can count batteries, checking
with a volt meter saves some work and money later. The motor will run on 24V... for
about 3 up and down cycles...then the insulation melts.
Nope. I checked the voltage: 19 volts or so right after the motor died.
I have a 24 volt tap on the back of the tractor, but that's an Anderson
plug and used for the Homelite stuff (which has not blown up despite it
being 18 volt equipment)
Now I am running it at 12 volts and it seems a lot happier.
In addition; GE did NOT re-wind the motor; it's a standard "12V" automotive motor.
They knew the duty cycle, which is part of what governs the winding temperature,
would be short. This is not unique. The starter motor in your car would melt if
you ran it at the nominal 12-14V for say 1/2 hour. The torque on a motor is proportional
to the current in the windings times the number of winds. The torque does not
know anything about voltage, BUT; the to get the current up requires voltage. To get
the current REAL high requires MORE voltage. That's when ohmic losses come and carry
you away; voltage=current times resistance. To get more windings you use small gauge
wire, which is higher resistance. In addition, the wire resistance increases with
temperature. This is something every motor designer deals with. So if a motor is not
expected to see continuous duty; the lift motor or a starter motor, you just design for
that case and hope no one tries to run it too long.
Hm. Then it's possible that Delco made different types of motors. I'll
post some pictures of the armature, but I will say it went from creamy
perfect to cremated. I ran it on 12 volts for about 10 minutes with nary
a problem, so I don't think it was a short. And just about all of the
windings on the armature were turned into burned caramel, so I don't
think it was a single short.
The other thing was the amount of commutator crud. I literally sanded
down the commutator with fine-grit paper just to make it shine. And the
condition of the field windings; they were burned and shorted.
Chris