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RE: NFC: A filter idea

	I am amazed at the (lack of) efficiency of power filters!

	AC motors turn in whichever direction where the AC current happens
to be the strongest. DC motors turn in one direction only. I suppose that
AC motors can be coerced to turn in one direction only by appropriate
winding of the coils inside. It has been a long while since my class on
Electric Motors and Generators :(

On Sun, 9 Jan 2000, D. Martin Moore wrote:

> > It is true that the swept vane design is more efficient than the
> > straight vanes found in most impellers.  However, the type of AC motor
> > used in these filters does not have a preferred direction of rotation,
> > and it may start rotating in either direction when the motor is
> > plugged in.  For this kind of motor, the straight vanes make sense. 
> Not talking about swept vs. stright vanes, but the direction of 
> rotation would be extremely important in my design.  How do you 
> design an AC motor to have a preferred direction of rotation?  I 
> guess I always assumed they all turned in only one direction.
> Prost,
> Martin
> ------
> "Cry to it, nuncle. as the cockney did to the eels when she put 'em i' the
> paste alive; she knapped 'em o' the coxcombs with a stick, and cried 'Down
> wantons, down!'"

Sajjad Lateef       <http://www.lateef.org/sajjad/>
sajjad at acm_org      sajjad at lateef_org