Re: car alternators as motors

[Robert McDonald <s348607@student.uq.edu.au>]

Hi,

R Subramanian wrote:

>         Hey Rob, I thought PM motors are AC????

not brushed PM motors, just brushless ones.  And apparently brushless motors
take a square wave input, not a sine wave like AC.

> > battery pack, use it to drive an alternator with the rectifier taken out
> > and then you'd have a source of AC to run an induction traction motor or
> > something!  It would be no where near as efficient as a proper inverter
> > or whatever you call them, but it would be a hell of a lot cheaper,
>
>         Would it? I don't know the cost of an inverter, but an efficient
> PM motor wouldn't come very cheap...
>
> > wouldn't it?  Hmmm... a bit of a messy solution though.  Speed control
> > etc would still be a problem...  don't mind me - I'm just rambling :-)
> >
>
>         Hmmm..lets see...if you vary the frequency applied to the PM
> motor, (I still think PM motors are AC...:-))...nope - requires an
> inverter to supply the PM motor - but, varying the frequency would vary
> ...this is too complex - I am going round in circles! :-)

ok I admit it is a silly idea, but if you were bored enough and had enough
spare time and parts, you could use a PWM controller running the DC motor then
... you're right this is a waste of time!! :-)

Rob.

> p.s. yes, alternators should be a good alternative to DC generators in a
> series (or even parallel) hybrid.

ok... but car sized alternators would be a little small for an APU... would
bigger ones still be cheaper than DC generators??

Hey is it possible to use an onboard charger to charge the batteries while
driving along???  What I mean is that you could hire a little diesel generator
that has a standard 240vac (australia) power point on it, that is designed for
use as a back up supply for normal appliances and stick the generator on the
back of a ute or whatever and plug the charger into it... I suppose the
charger would get all confused if you were drawing amps out of the pack while
the charger is trying to charge it...

sorry... more ramblings...
Rob.