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Jon Elson[_3_]

wrote:

I asked him if a 10
HP shunt wound DC motor I have kicking around would make a good
electric vehicle motor. He said that it would not be ideal but would
work OK. I was thinking that with only 10 HP the car would have a
pretty low top speed and poor acceleration. He said that pushing a
small car, like a Dodge Colt, would be easy if I didn't want to go
more than 45 mph. However, acceleration up to about 30 would be good.
He said that my 10 HP motor could put out 50 HP for short periods
without damage to the motor. Of course, he said, don't hold me to
anything, we're just shooting the breeze. But DC motors can put out
much more power briefly than continuously.
I drove the VW bug on electric power, using the GE jet engine
starter/generator. It is rated at 400 A continuous as a generator, and
about 1200 A for one minute as a starter. I had too-small battery
cables, so I was afraid to go over 250 A. But, the thing ran better,
I would say, that with the original VW engine. PLENTY of acceleration
and no trouble at all climbing steep hills. The only downside to it
was with the field current cranked way up (which you had to do to keep
the RPM in check with 48 V on the armature) it was VERY noisy. I started
the motor with a series resistor, then cut out the resistor to run the
armature directly off the batteries.

So, the starter/generator was rated at 12 KW (30 V x 400 A) but at
100 A and 48 V that was 4.8 KW or 6.4 Hp. (250 A at 48 V is also 12 KW
or 16 Hp.)

Jon