I support Mark Kinsler's comments in that it is preferable to use
a step-down transformer and keep the original motor as it is.  This
is what I have done on my Seeburg which still has its original motor,
although the lamps are wired directly to mains with 240 volt bulbs
utilising the American Edison screw base (which are readily available
over here).  I have increased the motor pulley diameter, of course,
as the motor rotates slower on the 50 Hz mains frequency.

With respect to Robbie's comments about Walter liking authenticity,
I believe that it is more authentic to _not_ rewind the motor so if the
piano returns to its home country in the future the 'conversion' can be
easily undone.  It is certainly cheaper with a transformer and doesn't
offend my purist principles!

Best wishes from the land of 240 volt, 50 Hz mains,
Nicholas Simons.

P.S.: They actually dropped the voltage a few years ago to 230 volts,
but nobody noticed.