The product Bill Chapman referred to in 060123 MMDigest is called
a "Green Plug", made by Green Technologies, Inc.  I can only assume
that Green Technologies is out of business as a web search turns up
a company by the same name that makes custom designed wheelchairs.

I remember seeing a display for the Green Plug at Home Depot
a few years back.  The display showed an electric motor and two push
buttons.  One button would run the motor with the green plug and the
other without.  When pressing the button that would put the Green Plug
in-line, there was a noticeable difference in sound: the motor ran
quieter with the Green Plug.

The display also claimed that the Green Plug would save on electricity
although it didn't specify by how much.  The main selling points seemed
to be to make the refrigerator run quieter and to save energy.  After
only a couple of months the display came down and Home Depot was no
longer selling the device.

Doing a web search on Green Plug I found only a few hits, but one item
that I kept coming up was a story about a guy who decided to test the
Green Plug on his refrigerator.  After a few months of running on the
Green Plug the compressor burned out and stalled.  The next time the
refrigerator kicked on (or tried to), the Green Plug burst into flames
and smoke.  He contacted the company about the problem; this seemed
to be something that happened with their product from time to time.
They replaced the compressor and the Green Plug.  Not very encouraging.
There may be very good reasons why Green Technologies, Inc., is no
longer in business.

The savings in electricity seem to amount to only two or three dollars
a year.  Technically speaking, these devices do save energy but playing
the player piano one less time per month would probably save the same
amount.

For the most part I think the Green Plug is probably not worth the
trouble.  It saves energy by slightly modifying the power that comes
out of the Green Plug and by providing less power to a motor during its
initial start-up phase, when a motor uses (and needs) the most amount 
of power.  This carries with it the risk that the motor may unexpectedly
not start-up one time or another.

Being that replacing (or rewinding) a player piano motor is a lot of
trouble and is expense, I wouldn't recommend using this device on your
player piano.  In fact, I wouldn't recommend using this device on
anything!

Ray Finch
Albuquerque, New Mexico