Mailing List flyrotary@lancaironline.net Message #32592
From: george lendich <lendich@optusnet.com.au>
Subject: Re: [FlyRotary] Re: Nothing to do with Rotary Engines, but....
Date: Mon, 10 Jul 2006 16:29:30 +1000
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
I'm wondering if any of this sort of information is relative
(donkey reference aside) to use of electric water pumps and how they run with reduced HP but seemingly provided  sufficient coolant transfer, even if they appear borderline power wise.
 
George (down under)
----- Original Message -----
Sent: Monday, July 10, 2006 10:46 AM
Subject: [FlyRotary] Re: Nothing to do with Rotary Engines, but....


What I was alluding to is the Fact that gas engines produce torque during a smaller portion of the 360 degree rotation. An electric motor on the other hand puts out torque for 360 degrees. Hence when using an electric motor to drive for instance, a  pump; instead of a 4hp gas engine one can use approximately a 2 hp and get the same pumping efficiency - like amount of water moved.  I think I came across the formula in an old Grainger catalog but it isn't in the one I have now. FWI
 
Wendell ( I'll disregard the donkey crap statement for the donkey)
 
 
Wendell,  Actually it depends on the elect. motor as well.  If its DC then there is continuous torque put out, but if its a single phase standard 1800 rpm motor.. it only puts out torque for 1/2 a rev. If its a 3 phase motor its nearly back to 360 deg torque due to it changing phases.  However at the end of the day.. it still has to raise the lb's so many feet to be 1 hp. 
As far as the donkey comment..  I was just trying to inject a little humor into a rather dry subject.. no offense intended. My appologies if any was taken.
 
Jarrett
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