Re: (ET) Electronic controller

["David Roden (Akron OH USA)" <roden ald net>]

On 7 Jan 2002 at 15:58, Bob Murcek wrote:

> For what it's worth I used a controller made for a PM field motor and 
> just
> kept the factory reversing method.  I used a Scoota 120 from
> http://www.4qd.co.uk/ and it's been working perfectly. 

I believe the ET motor is actually a compound, not 100% shunt, but this 
should work OK.  I have considered the 4QD controllers for mine, too. 

The advantage of a 4QD over a Curtis golf car controller is that the 4QD 
is a true ~speed~ control -- that is, it's designed to hold the vehicle 
at a constant speed.  When you move the speed potentiometer to a lower 
setting, for example, it will apply regenerative braking to drop the 
motor speed as quickly as possible.  (At least that's how I read their 
specs.)  Curtis will just let the vehicle coast -- OK in a golf car or 
road EV, I guess, but less desirable in a tractor.

The only cautionary note I would sound in using a controller intended for 
a PM motor is you should probably have some kind ot switching system that 
ensures that the field is always energized ~before~ voltage is applied to 
the armature, and that the field is always shut down ~after~ voltage is 
removed from the armature.  (This might not be so important with a 
compound motor, but it's still a reasonable precaution.)


David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1979 General Engines ElectroPed 24vdc
1970 GE Elec-trak E15 36vdc
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