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Old 04-13-2009, 04:16 PM   #908 (permalink)
Roger Heuckeroth
EV Converter
Join Date: Mar 2009
Location: Saugerties, NY
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Originally Posted by edown View Post
One more question: I have Bob Brant’s book “Build your own electric vehicle” and he stresses using a large inductor (choke) in series with the motor to “control armature ripple current”..
“20 turns of 1/16” x ¾” copper on a 2” x 2” core” Do you think this would help, or is it just not necessary?
I don't think its needed in the motor circuit to protect the motor. Where I have seen this suggested more often is on the B+ side of the controller. In that location it smoothes out the current being drawn from the batteries. More specifically it acts as a low pass filter to keep the ripple current away from your batteries. Batteries get hot and experience shortened life when exposed to a lot of ripple current. The capacitors in your controller remove most of the ripple, but there is still some ripple at the batteries. A properly sized inductor will completely eliminate that ripple current from the batteries.
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