UQM PowerPhase125 Electric Car Motors

by Tom Villars
(Washington DC)

I'm interested in investing in UQM and would like to hear your opinion on their new product the PowerPhase125.

In quantities of over 200,000/year they are quoting a price of $1418 for both the motor and controller. I'm not an expert but their spec sheet seems to address many of the concerns you've raised about DC motors. Is this a viable alternative for a mass produced EVs?


Hi, Tom -
Is it a viable alternative? Yes, I think it is.

Toyota must have thought so, too, because this is the same type of motor they put in their Rav-4 EV back in the day.

The UQM Powerphase motors are brushless per-mag motors which - as I look at the spec sheet (pdf) - have qualities of the AC motor and also qualities of the DC motor. The torque curve looks like a typical golf cart motor, but when powered by 300 or so volts, it just feels like a rocket. Who cares that it tops out at 75 mph or thereabouts?

I really, really like what little I've seen so far - like this gorgeous Lotus Elise conversion with the UQM Powerphase 75 inside. (The difference between the 75 and the 125 is that the 125 is more powerful - but basically the same motor.)

As far as investing based on my opinion? I really liked Phoenix Motorcars and those Altair NanoSafe batteries, too - didn't keep them from going bankrupt.
Shows you what I know; )

Regards,
Lynne

Radial flux electric car motors

by Tom
(Sydney, NSW, Australia)

What are the advantages of Radial flux AC induction motors? From what I have read, Axial flux motors have a higher efficiency and lower volume per power and energy basis. Is it just the dimensions that inhibit them from being more widely used?


Hi, Tom -
I'm sorry, but I have no idea. Axial flux motors, I've heard of them being used in hub motor applications, as in the video above...but I'm not familiar with radial flux motors.

You might try the guys over at the EV Discussion List, or maybe someone else can comment?

Regards,
Lynne

Brushless DC Motors

by Anonymous
(Little Switzerland, NC, U.S.A.)

I may be showing my ignorance, but I believe brushless DC motors run on three phase AC. Why is it called a DC motor?

Well...
Brushless DC motors run on batteries when you put them in an electric car, and 3-phase AC induction motors do the same. That's not the part that makes classifies them as AC or DC electric motors.

Wikipedia's opinion: "...more a de facto convention rather than a rigid distinction."

Brushless DC (BLDC) motors DO look and act a lot like 3-phase AC induction motors - including needing a more complicated controller than a series wound DC motor - but the torque curve of a BLDC motor is more similar to a permanent magnet DC motor (because that's basically what it is), and induction (slip) doesn't generate torque as it does in a 3-phase AC induction motor.

Please check out ZEVA's excellent motors page for an animated illustration of these electric motors!

Regards,
Lynne