Re: what is the max bus voltage, 300V?

[Lee Hart <leeahart@earthlink.net>]

David Dymaxion wrote:
> Car without regen burns up brakes down a hill = big lawsuit.
> Solution: AC.

Except that normal cars don't have regen; they get along just fine. And
regen can be done with any motor, AC or DC. It is exceptionally easy
with sepex DC, for example.

> DC system is easy to modify, customers start adding things like
> bypass contactors, raising the voltage. Could lead to an expensive
> lawsuit. AC is much harder to tinker with.

The auto companies don't have any problem building even the simplest
things so they are impossible to fix!
 
> DC has full on failure modes.

So AC EVs. So do normal cars. You just have the engineers deal with it. 
> Foreseeably silicon will be cheaper than the copper and iron motor,
> so eventually it could be cheaper to put more into the controller,
> and use a cheaper common AC motor.

We've discussed this one before. "Eventually" may take decades. There
are going to be both AC and DC motored EVs for a very, very long time
yet.

> Gearboxes are only cheaper for converters because it is already there
> -- try pricing a new transmission for fun sometimes! Wide AC
> powerband helps save on tranny cost when designing from scratch.

As we've discussed before, the wide power band is not intrinsic to AC;
it's a consequence of a purpose-built drive system. Trains and buses
have used DC traction motors and direct drive for many decades -- they
work, too.

> Advertising: Do you want to say you are using 100 year old technology
> or the latest and greatest?

Advertising deals with fantasy, not facts. They can make up anything
they want :-)

> What has surprised me is sepex hasn't been more popular, it seems
> like a good compromise between AC and DC.

The main problem has been a lack of suitable motors. Almost all
on-the-road EV motors are borrowed from some other application, so they
are not really an optimal choice.

-- 
Lee A. Hart                Ring the bells that still can ring
814 8th Ave. N.            Forget your perfect offering
Sartell, MN 56377 USA      There is a crack in everything
leeahart_at_earthlink.net  That's how the light gets in - Leonard Cohen