Re: car alternators as motors

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

Thomas Shay wrote:

>    Simple DC generators  ran into design limitations about 1960
> when larger generators were needed to cope with the increasing
> number of electric accessories.  They had no interpoles and
> couldn't be pushed to deliver higher currents without sparking
> problem and brush/commutator problems.  Also reliable,
> compact and cheap silicon rectifiers had become available
> and made it practical to build AC generators with internal
> rectifiers.
>   Switching from generators to alternators solved the current
> limitation problem and as a bonus eliminated the trouble
> prone brushes and commutators.
>
> Tom Shay     1983 Ranger pickup conversion

  Hi Tom,
when using auto alternators as they were designed, what is their efficiency??  Is it
upwards of 80%??  This may be just another theoretical but impractical idea... but if
alternators were fairly efficient, you could run a high efficiency DC motor (eg PM) off
the 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, 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 :-)

Rob.