Electric Motors

Post by **shyouss** » Mon, 05 Oct 2009, 21:52

Dear friends,
Electric motor is the heart of any EV. Which electric motor do you think is the best option for an electric vehicle and what are your criteria to choose one? It is a good idea if you can combine your personal experiences with some technical information and details so an amateur like me can take more practical benefits from this topic discussion. Thanks

Post by **shyouss** » Mon, 05 Oct 2009, 21:58

One of the interesting articles that I read recently was the use of SUPERCONDUCTORS and liquid nitrogen to minimize electric resistance and inducing more magnetic fields in an EV electric motor. Does anyone knows if this technology has been used in a significant scale in any EVs yet?

Post by **Electron** » Tue, 06 Oct 2009, 01:35

shyouss wrote: Dear friends,
Electric motor is the heart of any EV. Which electric motor do you think is the best option for an electric vehicle and what are your criteria to choose one? It is a good idea if you can combine your personal experiences with some technical information and details so an amateur like me can take more practical benefits from this topic discussion. Thanks

Series DC motor, just look at it's torque curve and past history.
A good subject for discussion at a branch meeting.

Ron

Post by **evsports** » Tue, 01 Dec 2009, 22:31

DC motors are cheaper and simpler but suffer from brush wear and losses. ac motors should be three phase to take full advantage of their efficiency. (More than three phases add efficiency but at greater weight and cost which outweighs the added efficiency. 3ph = 96%, 4ph ~98%) Switchmode controllers that are needed for DC motors are not really much simpler than three phase Inverters, which have a better control over both speed and torque than DC machines. Suitable ac machines should however have laminations suitable for higher frequencies than 50 hertz, preferable up to 200 Hertz. (or higher) The frequency also determines the weight of iron required for the motor, therefore (large) aircraft use 400 Hertz making a motor of the same output about 1/8th the weight of a 50 Hertz motor. That doesn't have to mean that the motors have to be high speed either. Note the sound a Fisher and Pykel (F&P) washing machine motor makes, the same sound as an electric train, and for the same reasons. The motor is driven by a variable frequency driver. The F&P motor might even be adapted to driving a light vehicle such as a motor cycle, where it would be directly mounted in the hub. The best electric vehicle motor is not yet in existence, but necessity will soon have designers making the changes needed. Some motor manufacturers are already experimenting with three phase battery powered hand tools. (i.e. DC power switched to drive a permanent magnet 3 phase motor in the tool.) The F&P motor uses permanent magnets, three phases, and multiple poles, the number of which I am not aware of, directly driving the machine bowl so there are no transmission/gear/belt losses.

Post by **gmacd33** » Thu, 28 Jan 2010, 03:46

I see Kostov motors have recently appeared on the EV Works website - anyone have any experience of them? I see they are a fair bit cheaper than the Netgain ones of similar size?!?

Post by **7circle** » Thu, 04 Feb 2010, 04:21

Wow shyouss

"One of the interesting articles that I read recently was the use of SUPERCONDUCTORS and liquid nitrogen to minimize electric resistance and inducing more magnetic fields in an EV electric motor. Does anyone knows if this technology has been used in a significant scale in any EVs yet?"

My AEVA Search found only your one post, referring to the Superconductor Motor technology

Here was one I saw back when it first popped up in 2008.

The SUPERCONDUCTOR technology did make it to a proto type:

http://pinktentacle.com/2008/06/superco ... c-vehicle/

But they haven't released any newer R&D

There must be others out there!

More info at:
See Page 2

http://global-sei.com/super/topics_e/index.html

Interesting reading on there site.

Wonder how further they have got since 2008.

and .. My First post

AEVA has Great forums created by its members.

Post by **coulomb** » Thu, 04 Feb 2010, 05:31

Welcome! So many newcomers lately.

I think the big problem with superconductors is the energy needed to keep the conductors cold enough. For an EV application, you'd need more power for the refrigeration that you would save on copper losses.