Electric water pumps (was) alt charging cont sw

[steve ravet]

Bruce Plecan wrote:
> 
> -----Original Message-----
> From: steve ravet <steve.ravet at arm.com>
> To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
> Date: Sunday, March 14, 1999 11:32 AM
> Subject: Re: Electric water pumps (was) alt charging cont sw
> 
> Think about how much motor/pump it takes to do 100 GPM....
> (I'm guageing this on the 180 GPM Stewartcomponents mentions
> at 9,000 rpm).
> You might need 10-15 at idle..
> Or am I missing something here
> Bruce

It probably makes sense to drive the water pump mechanically, more flow
at higher RPMs.  But it seems like A/C, AIR, and PS would work better at
a constant RPM.  Or in the case of PS, lower RPM at higher road speeds. 
Just wondering out loud.

--steve

> >
> >But, isn't it inefficient to spin all those things at engine RPM rather
> >than a constant RPM?  Seems like a pump/compressor that has to work over
> >a 10:1 input speed ratio wouldn't be as efficient as one designed to
> >work at a constant RPM.  Like A/C, and esp power steering.  If those
> >were designed to run w/electric drive at constant RPM maybe they'd be
> >more efficient.  Especially if you had a dual voltage alternator and ran
> >the accessories at 100V 3phase.  maybe?
> >--steve

-- 
Steve Ravet
ARM, INC
steve.ravet at arm.com
www.arm.com