Re: car alternators as motors

[Thomas Shay <tshay@ix.netcom.com>]

Robert McDonald wrote:

> Can someone please explain to me why cars use alternators instead of just plain DC
> generators??  Is it to do with the variable speed that they have to run at??
> (wild guess)

   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