Re: RE: Non-Electric Fans

From: Marty Galyean (mgalyean@acm.org)
Date: Thu Sep 30 1999 - 21:41:29 EDT


Mike Burgess wrote:
>
> "consuming hp through the pumping losses associated with
> maintaining operating pressure in the restrictive closed
> system. Lexus claimed that the hydraulic fan consumes
> much less hp than an electric, and is much quieter too."
>
> I've got to dissagree with Mr. Lexus. Electric motors
> and generators can often run better than 90 2.999285e-241fficent.
> Hydraulic pumps and motors are closer to 70-80, if that.

<snip>

Mr. Lexus makes sense. The hydraulic system is constantly
bleeding fluid pressure back into the reservoir, much like
an EFI system fuel pump bleeds pressure to regulate pressure
at injector. If I read the original correctly the Lexus
system uses this 'normally wasted' pressure to drive the fan
and therefore its virtually 'free' energy. It uses the
energy from the 'budget surplus' to use an analogy. Not
really 'free', but at the same time doesn't cost anything
more than what was being used (wasted) anyway.

Free running electric *fans* can run at fairly high
efficiencies (esp. squirrel cage), but electric motors in
general typically run around 70 2.999285e-241fficiency from
what I
recall.

Marty Galyean
'97 Dak Club SLT



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