Electric water pumps (was) alt charging cont sw

[steve ravet]

Bruce Plecan wrote:
> 
> -----Original Message-----
> From: Clive Apps Techno-Logicals 416 510 0020 <clive at problem.tantech.com>
> To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
> Date: Sunday, March 14, 1999 12:25 PM
> Subject: Re: Electric water pumps (was) alt charging cont sw
> 
> OK, but a 1-2 HP electric motor is alot of weight, no?.
> Then the waterpump coupling (mechanial/coolant), and pump itself.
> Now a hydralic pump is another matter, since at low speed it's use could be
> shared with the power steering, or for running a supercharger off of
> hydralics.
> Bruce

Just FYI, Summit shows 4 electric water pumps, 2 race only and 2 that I
guess are OK for street.  5.8 amps for the street one, 3.5 for the race
pump.  That's about 72 watts for the street pump, or about a tenth of a
HP.  30-35 gpm flow, 9psi static pressure.  They're real proud of them,
at $260 for SBC.

Can any mechanical guys speak up on if a constant rpm pump gains enough
efficiency over a variable rpm pump to make up for the
mechanical/electrical/mechanical conversion?

--steve

> 
> >> 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
> >
> >no pressure head
> >it just moves the stuff around
> >probably a lot of power is not required
> >maybe 1-2 HP
> >Clive
> >> >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