In my youth, a good 35 years ago, I found a junk upright Pedal
Electric Duo-Art to restore here in the UK.  I remember finding this
large heavy mysterious felt "horse nose bag" hanging in the right
lower side of the piano.  In those days everything about Pianolas
was mysterious to me.

Inside was the Motora turbine pump.  I rebuilt it with new bearings,
balanced the fans and reassembled it with care.  I do remember being
surprised at the difference in quality between the rough Motora and
the rest of the Duo-Art.  To cut a long story a bit shorter I did
manage to get 24 inches of suction out of it by upping the voltage
a tad, but it ran even hotter.

I finally ripped out the unit from its quite neat housing and
replaced it with a vacuum cleaner motor that just fitted.  It ran
quite hot as well but at least it supplied an adequate vacuum.
Both were too noisy for me and I promptly sold the whole thing and
bought I nice Weber with a "Steamboat" pump in it.  The original
Motora innards are still with me, sitting on a shelf beside me
even as I write this.

The moral?  Don't waste time on your Motora unit if you want your
Duo-Art to work well; junk it.  I think this is one of those rare
occurrences where original is not good enough.  And now?  I have
a very nice upright Steinway PEDA with a box pump.  And what am
I doing?  I'm busy assembling a remote "Steamboat" pump as I have
decided that any pump inside a piano is too noisy for me.

Don't worry, this time I will keep the original pump in it for
originality's sake.

Regards,
James Black