[ausev] High torque or High RPM?

[Chris Robison]

On Thu, 2007-12-06 at 13:31 -0600, Donovan Becker wrote:
> Josh,
>  
> We might be able to give you a better idea of whether or not to use a
> motorcycle or car tranny soon. I'm working with Gary K on his electric
> trike. (www.zwheelz.com for pics) We're using a 30kw AC induction
> motor with an off the shelf motorcycle tranny similar to what Harley's
> use. Our vehicle will run about 3000 lbs with 24 lead acids, and we're
> hoping to get similar performance specs to what you're looking at.
> It's conected via belt drive so we'll find out whether the tranny or
> belts will give first, or ideally not give at all. The motor at 30kw
> is a pretty good size and has regen braking, a 90000 rpm range, and
> liquid cooling so we can beat it up continuously w/o over heating:)
 
Inductive AC motors lack a commutator and therefore have a torque
characteristic that's much kinder to transmissions and drivetrains.
Moderate torque and high RPM. However, if your motor is truly capable of
90,000rpm, I'd be very impressed that you've found a transmission and
belt drive that will tolerate it!  :-)

I suspect it's closer to 9,000rpm. Some AC motors are capable of
10-12krpm, but I haven't seen many that go higher.

A sealed case and liquid cooling is a huge plus for AC as well, and is
very difficult to imagine on a DC motor.

The big downside is cost. And with the Siemens systems, that high pitch
whine.

  --chris