Chevrolet Volt will have liquid cooled batteries.

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Sep 19, 2007 | 05:34 PM

#61

jg95z28

Registered User

Joined: Sep 2002

Posts: 9,705

From: Oakland, California

Quote:

Originally Posted by Eric Bryant

Is that the input power to the train, or is that the architecture of the motors? There's a big difference. I'm guessing that your traction motors use AC drive, because damn near everything else either has gone that direction or is in the process of doing so.

You're right of course.

I'm just a civil engineer and mainly deal with the track and stations. We take 34.5kV AC down to 1000v DC to power the 3rd rail, which is then picked up through collector shoes by the trains, which in turn covert it over to AC to run the AC traction motors.

Sep 19, 2007 | 10:27 PM

#62

LS1_Disciple

Registered User

Joined: Jan 2003

Posts: 100

From: Colorado Springs, CO.

Quote:

Originally Posted by Eric Bryant

It will certainly be AC - DC is all but dead for traction applications.

The mod potential for this thing will be enormous - huge gains could be had by playing with phase advance (a software change), changing the controller's target V/f constant by increasing the modulation index (yet another software change), or physically rewinding the motor to change the Kv and Kt constants. Once people get their heads wrapped around EV architecture, modding the internal combustion engine is gonna seem like a total PITA. It'll be a good time to be an electrical engineer

The warranty claims that result from all of this tinkering should be entertaining as well.

You know, I had to take 1 circuits class in college and that was one too many. I think driving a full-electric car would trigger flashbacks - every time I went to start it, I'd expect a pop quiz.

Give me cams and valves any day.

Sep 20, 2007 | 11:00 AM

#63

R377

Registered User

Joined: Nov 2000

Posts: 2,712

From: Ontario

Quote:

Originally Posted by Eric Bryant

The push to AC is not universal. AC was looking to take over the freight locomotive industry, but DC is still simpler, cheaper, and better understood. A surprisingly large percentage of new freight locomotives are still built with DC power.

Sep 20, 2007 | 06:14 PM

#64

Eric Bryant

Registered User

Joined: Aug 2001

Posts: 2,400

From: Michigan's left coast

Quote:

Originally Posted by R377

Yep, but as semiconductor prices continue to drop and fuel prices continue to creep up, my guess is that AC drive continues to increase market share.

Also keep in mind that the cost of adding regenerative charging (as opposed to "mere" regenerative braking) to a DC system will add substantial costs and thus decreases the cost advantage relative to AC.