Re: Electrical Pendulum Drive (was Re: moon's synchronism)

[brian whatcott <inet@intellisys.net>]

At 22:44 3/20/98 -0500, you wrote:
> ... are you sure the "60 Hz
> solenoid" is actually exerting a 60 Hz force on the pendulum?  Pardon my
> disbelief (or lack of understanding), but please verify.
> ...
> Bob Sciamanda 

The stationary solenoid exerts a force on a conductive bob comparable
to the force applied by the stator of an induction motor on the
squirrel cage rotor.

"The effect can be made stronger by placing a capacitor in series with 
the coil so that the combination resonates slightly below the 60Hz 
frequency of the power line."

 Versions of this drive can operate with a ferromagnetic bob or a 
conductive bob. There is a power assymmetry as between the bob approach 
and the bob departure in either case which effectively modulates the 60Hz
current. A change in inductance causes a marked change in current, so the
current rises with the approach of the bob. The current peaks however,
after the bob has passed the center of the solenoid. It is this unbalanced
force
 which maintains the pendulum in a strikingly simple way.

Whatcott    Altus