[gagendel]

Here's a look at some things to come:

I just got my June 6th edition of design news magazine. They had an article by Raser Technologies( http://www.rasertech.com/ ) where they put their electric motor in a Formula Race car to demonstrate it's capabilities. It's enough hype to drool over.

The big claim is that they don't loose efficiency like standard induction motors when they're operated beyond their torque range. Only 3-4% drop in efficiency at 4x their torque range as opposed to ~60% drop normally. It's also significantly cheaper to build one of these than the permanent magnet engines ( like Toyota uses ).

They aren't letting much out of the bag because their waiting for their 20+ patents applications to come through.

BTW, This is the engine that the US Army is putting into their next generation Hummer.

Here is the comparison with the Prius engine:

Prius (Toyota)
-----------------------------------
Motor type: Permanent Magnet
Torque: 400 Nm ( 295 ft-lbs )
Dimensions: 205 x 320 ( est. )
Volume: 16.5 L ( est. )
Torque Density: 24.3 Nm/L
Weight: ( not published )
Cooling: Liquid

Symetron P2 (Raser Tech)
-----------------------------------
Motor type: AC Induction
Torque: 570 Nm ( 420 ft-lbs )
Dimensions: 205 x 320
Volume: 16.5 L
Torque Density: 35 Nm/L
Weight: 67 kg
Cooling: Air
Power:
179 kW (240 HP) @3000 rpm
373 kW (500 HP) @6250 rpm

 

[RSnyder]

It can run air cooled for 60 seconds, but what about a four hour trip through the mountains? The two motor/generators in the Prius are active during most driving, even though the battery isn't always involved.

Reduced weight and reduced cost are always good things (if they don't involve reduced functionality).

Can it generate. It seems like it ought to be able to, but they don't come out and say so, which makes me suspicious. Hybrids rely heavily on generation as well as motoring.

Another annoyingly missing figure: input voltage. It's easy to increase torque by increasing the input voltage, but there are other issues, like battery weight.

Finally, with current going to the rotor, are there any conditions where arcing occurs (maybe as the motor ages)? Don't want to be making ozone at highway altitudes.

They claim 92% peak efficiency at 3000 RPM. Toyota doesn't publish efficiency numbers, but many estimates in the 85% to 95% range have been suggested based on Prius performance. With little to no efficiency gain, weight and cost reduction will need to carry the day.

Well, hopefully they'll discuss this kind of thing with serious investors, but the rest of us will just have to wait until real products ship I suspect. The real question is: Will it give a hybrid or other electric motor powered automobile manufacturer enough competitive advantage to make it worthwhile?

 

[clett]

Elsewhere on the website they say that re-wiring existing motor designs with their windings leads to a ~3x increase in torque capability - which would mean a lot more power from the Toyota motor.

But as mentioned the limiting factor for increasing EV power in the Prius is not the motor but the battery and inverter.

 

[RSnyder]

Elsewhere on the website they say that re-wiring existing motor designs with their windings leads to a ~3x increase in torque capability - which would mean a lot more power from the Toyota motor.

But as mentioned the limiting factor for increasing EV power in the Prius is not the motor but the battery and inverter.

The Prius uses permanent magnet motors. The Raser designs are inductive motors. So it's a bit of a stretch to suggest that their rewiring could help a Toyota motor. I think if you want to use Raser technology in a Prius, you'll need to buy a couple new motors that are already configured as induction motors.

 

[clett]

RSnyder, good point! I stand corrected.

 

[Hobbit]

I haven't heard of *anyone* getting good regeneration
performance from an induction motor -- not that I've
researched it heavily or anything, but there doesn't seem
to be anything really positive in the literature. Solectria
tried. The industry seems to have given up on that and
now favors PM as good for regen.
_
The only other option is a field winding, right? Which
gets into the issue of slip-ring maintenance, etc...
_
_H*

 

[clett]

The AC-propulsion T-zero, and GM's EV1 both have great regenerative capability (the T-zero can be driven without the brake pedal most of the time, and the EV1 had a 44% increase in urban range with regen switched on). Both use AC-induction motors, so they can't all be that bad.