[DeTomaso] Electric Water Pumps, The 21st Century of Water Circulation

Guido deTomaso guido_detomaso at prodigy.net
Sat Apr 13 16:08:13 EDT 2013



Shooting from the hip here, I'd say we'd expect an alternator/generator to have 
a linear output to rpm.  The faster it turns, the more magnetic fields are 
moving past wires, which pushes the electrons, so to speak.

But unwanted physical effects, electrical resistance, loss of "saturation", etc, 
soon flatten the curve.

OTOH hand a non-positive displacement pump ( like a water pump or turbocharger, 
not like a rootes blower ) we'd expect a non-linear output, as most of your 
formulas for centrifugal acceleration have a squared component, but again 
physical factors flatten the output curve as some optimal point is reached.

As a practical example, I believe Paxton centrifugal superchargers of yesteryear 
have a small transmission to slow them down at high rpm, to create a more linear 
output.  Whereas the aforementioned rootes blowers typically run at a constant 
ratio to the crankshaft speed.

Or, I could be wrong.

GD



________________________________
From: "MikeLDrew at aol.com" <MikeLDrew at aol.com>
To: guson at home.se; eb0711 at kolumbus.fi
Cc: detomaso at poca.com
Sent: Sat, April 13, 2013 12:26:41 PM
Subject: Re: [DeTomaso] Electric Water Pumps, The 21st Century of Water 
Circulation


In a message dated 4/13/13 12 16 42, guson at home.se writes:


> 32 A is the max output and that won't supply lights and engine cooling 
> fans reliably unless you keep the engine at constant redline.
> 

>>>At the risk of showing my electrical ignorance, which is considerable 
and profound....

I didn't think alternators had a linear output (unlike a belt-driven water 
pump, where the volume pumped is directly proportional to engine speed).  
Don't alternators generate their output almost regardless of engine rpm, from 
just above idle to redline, with power output 'trimmed' by the voltage 
regulator based on electrical demand?

Mike
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