Need for Speed: AC vs. DC motors

by Tim
(Chandler, AZ)

I'm considering converting a Mazda Miata to an electric car, and I've learned a lot reading your site. I really liked the page you have concerning AC vs. DC motors. You make some very convincing arguments for AC. I stated doing research, specifically looking at the data entered for AC conversions on the EVAlbum online.

I was surprised to see that so many of them list the acceleration as slow or "not what they'd hoped." All of the points that you've made for why an AC system is better are quite good, but can you tell me is the trade off that you have a car which is slow off the line? I'm not looking to build a dragster, but 0 to 60 in 25 seconds just isn't acceptable.

All things being equal (batteries, volts, amp/hours etc) is an AC system simply going to be slower than a DC system? If I want an AC system is the price of that a slow car?

Hi, Tim!
You know, I've been pondering this myself for quite a while.
I thought...Hey, why not have two motors, one AC (for efficient use of your batteries on the freeway) and the other a series-wound DC (for brisk acceleration from a standstill)?
Turns out I wasn't the only one thinking along these lines. I'll quote "Build Your Own Electric Vehicle" (p. 57, second edition) once again: Darwin Gross (EV engineer) says "the ideal EV drive for tomorrow has...DC (motor) to get started, AC (motor) to run over 30 mph."

Sounds like a whole new hybrid to me!

Regards,
Lynne