Re: Rotary gap motor

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
> 
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<FutureT-at-aol-dot-com>
> 
> In a message dated 3/27/02 10:49:06 AM Eastern Standard Time,
> tesla-at-pupman-dot-com writes:
> 
> Jeff,
> 
> See my website at:
> 
>   http://hometown.aol-dot-com/futuret/page3.html
> and     http://hometown.aol-dot-com/futuret/page6.html
> 
> It depends on the size and weight of the rotor disc.
> I've built rotary gaps with tiny motors, and with larger
> ones.  When a tiny rotor is used, a tiny motor can be
> used.  I've used 1/50th HP motors and smaller for a
> 42" spark output.
> 
> Cheers,
> John

	Somewhere I have an old NACA report which gives the power required to
turn a disk of given diameter and a given speed.  Can't find it, but
seems to me the power varies at least as the cube of the diameter and
the fourth power of the speed.  The actual formula I remember was that
the variation was as the cube of the speed and the fifth power of the
diameter, but that doesn't agree.  Anyhow, the windage goes up real fast
as you increase the diameter!

Ed