[ExI] Electric cars without batteries

John Clark jonkc at bellsouth.net
Sun Oct 24 17:28:45 UTC 2010


On Oct 24, 2010, at 11:49 AM, Keith Henson wrote:
> 
> The power output from a turbine is the product of the RPM and the torque.

I know, so the faster the RPM the weaker the torque. Gas turbines have very high RPM's.

> you can use any RPM for an AC generator.

Provided you have something with enough torque to turn it.

> It just changes the frequency.

Electrical frequency is not the problem.

> Reduction gears reduce the speed and increase the torque while introducing loses.

That's the problem.

> At the time I worked in the EMD plant, locomotive engines ran at 900 RPM.
> It would be no problem to replace one with a equal power 9000 RPM turbine.

And some gas turbines have an even slower RPM than that, but they tend to be HUGE, the sort found in power plants, more typically they operate between 10,000 and over 100,000 RPM, the smaller the faster, and the one in a car would be a lot smaller than the one in a locomotive.

> The point is that after you have electric power you can
> drive electric motors over a wide speed range.

But to get that electricity you need a gas turbine and they operate most efficiently under a constant load. That's not the sort of load you expect from a car, it's constantly accelerating and decelerating.

  John K Clark


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.extropy.org/pipermail/extropy-chat/attachments/20101024/3ec67d52/attachment.html>


More information about the extropy-chat mailing list