I agree that the Curtis controllers used in this manner are quite
practical. And now I'll share my secret: I have top speed WITHOUT
weakening the field. I use a larger motor pulley with a smaller trans.
pulley, sized appropriately to achieve top speed with full field voltage.
Since speed control with an electronic controller is almost
infinite,losing the lower gearing is of no great consequence.
Additionally,I don't use *any* contactors,only a master disconnect
switch. The switch on the pot is used to turn the KSI (Key Switch Input)
on the controller on and off. A toggle switch with center off is used to
reverse the field polarity thereby achieving motor reversal.The center off
turns off the KSI,requiring the foot pedal to be brought back to neutral
to restart.This prevents slamming from F to R while the motor is running
and also gives a bit more time for the field to collapse before polarity
reverses.I do use a varistor to help with that,though.
Sincerely,
Harold Zimmerman
Clean Power Supply
Ephrata PA
717-859-4234
Parts Supplier for GE Elec-Trak,New Idea& Wheel Horse Electric Tractors.
On February 10, 2011 at 4:05pm -0500, you wrote:
I am here to tell you the answer is simply and emphatically YES.
I have an E15 w/a Curtis 36V golf car controller in it. When you step on
the
"go" pedal (it's an E-15, but I put a pedal on) a microswitch closes which
energizes two contactors' coils. When the contactors close, they energize
the field windings (full 36v across the windings) and energize the
controller. Further motion of the pedal turns a 5k pot (a very familiar
set-up to those of you who have messed with Curtis controllers, not to
mention others) which increases the current from the controller through the
armature. Off you go!
A simple DPDT allows reverse (an h-bridge for reversing the field winding
current). I plowed with that set-up for two winters... worked great.
Buttery
smooth! Just not much of a top speed w/o the field weakening.
I have NOT put field weakening on that set-up, but it would be easy enough
to do using relays and an original resistor card.
Note that sometimes you can find Curtis 36v Sep-Ex controllers on ebay for
short money... I have one that I intend to put in another E15 whose
original
control system was badly damaged. Got it for $79 last year... looking
forward to trying it out.
Oh, speaking of which:
http://cgi.ebay.com/4-CURTIS-PMC-SepEX-DC-MOTOR-CONTROL-24-36-VOLTS-400-AMP-/110642253704?pt=LH_DefaultDomain_0&hash=item19c2cacf88
Best to all,
-Max
On Thu, Feb 10, 2011 at 3:00 PM, Neil Dennis<wombatt gmail com> wrote:
Just a thought, can you use a PWM type control on that motor ? Or change
to a PM motor and then PWM ?
wombat
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