From: "David Roden (Akron OH USA)" <roden ald net>
To: elec-trak cosmos5 phy tufts edu
Subject: (ET) Using 4QD controllers
Date: Thu, 05 Jun 2003 11:17:23 -0400
This is forwarded with permission from a message sent to me by Christopher
Goddard. He was responding to my post about using a 4QD controller in an
ET.
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I have used many 4QD controllers (very commom in UK) to power separately
excited motors. The simple way is to use the brake drive output to drive a
relay which switches the field on. The brake drive is energised just before
the controller output comes on and drops out just as the output drops to
zero.
With a 4 quadrant controller this gives smooth control in drive and regen
braking. I suppose a cheaper solution would be to use a 2 quadrant
controller and achieve reverse by simply reversing the field current with
relays.
I also have an International Cadet 81 which I converted some time ago to
electric power with an E tech motor and 36v 200amp 4QD controller. Works
very well but have doubts about the transaxle strength!
A few years ago I built from scratch an electric tractor running a Lynch
motor at 48v and 300amp controller. It is very lively and capable. Really
hard work, shame it seems to have been taken over by 7 year old son!!
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David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1970 GE Elec-trak E15 36vdc
1974 Avco New Idea 36vdc
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