sepex problem distilled

I think that this post distills the sepex issue well. Inspires me to keep trying with the two sepexs

from:

http://www.mail-archive.com/ev@listproc.sjsu.edu/msg06741.html

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On 7/31/06, David Roden <[EMAIL PROTECTED]> wrote:

On 30 Jul 2006 at 21:22, Michaela Merz wrote:

> There are quite a few disadvantages with the available DC
> technology, regen braking, overspeeding of motors without load, full power on
> failures of controllers, just to name a few.

Ah, but the first two of these limitations are not characteristic of
seperately excited DC motors.  They are limitations of the series-wound
forklift motors that most DCers run >because they are relatively cheap and
readily available<.

Exactly.  Most production EVs in Europe have a very nice Sepex drive,
using a Sagem controller and Leroy-Somer motor.  As a package, it has
none of the disadvantages mentioned above, and it's single ratio as
well.  In fact, I'd challenge any AC car to regen to an absolute stop
as well as my sepex one does!

The problem is that there are few readily available sep-ex motors and
controllers suited to road EVs. I don't see this changing any time soon - in
fact with the adoption of AC induction motors in forklifts, it seems more
likely that those drives will fall to the price range that hobbyist EVers
are willing to pay before sep-ex drives do.

Probably true.   However I'm sure that anyone who really wanted could
take an ADC or similar old fashioned DC motor, have the field rewound
and make a really powerful sep-ex system out of a Zilla and a seperate
PWM field controller.

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