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Re: Synchronous Motor buy



Tesla List wrote:
> 
> Original Poster: "Paul Mathus" <pmathus-at-learningco-dot-com>
> 
>      Folks,
> 
>      I found a motor for sale in a catalog and was wondering if it would be
>      appropriate for use in an SRSG:
> 
>      Globe Model #186A147 Dual Shaft Synchronous Motor - $14.50!
> 
>      - Rated for 115VAC 60Hz 1 Phase 3600 rpm
>      - torque: 5 oz-in cont. 14 oz-in stall
>      - Requires 6 mfd cap
> 
>      Will this type of motor synchronize correctly?
>      I realize there are major issues with the low torque rating of the
>      motor, but wonder if you couldn't work around them using extremely
>      light electrodes and rotor, and maybe gearing down 2:1 or 4:1 to
>      increase torque.
> 
>      just an idea. .  .
> 
>      thanks,
>      paul

	At relatively high surface speeds, the primary source of drag (which
results in torque) is air friction.  (Don't have the windage formulae
handy, but seem to recall that the torque goes up as the fifth power of
the diameter and the square of the rpm).  For such a small motor I
suspect this would mean a very small diameter rotor.  You will probably
be disappointed.

Ed