Electric water pumps (was) alt charging cont sw

[Greg Hermann]

>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?

You still need more water flow AND head at higher engine speeds!

Greg
>
>--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