Dear MMDers,  It is with great interest that I have been following the
recent thread about testing wind motors.  For the first time in 20
years I am dealing with a motor which has me terribly stumped, so I'm
fielding some questions in hopes that someone has vast experience with
Lauter pouch type wind motors.

First, does the 'plug the vacuum supply nipple and turn the crank
backwards' test apply to these pouch motors?  Frankly I can't see how
it can, as the way the vacuum lines are drilled and timed in this one,
a pouch that's pulling vacuum can just borrow the air from some pouch
that's exhausting.  Am I missing something here?  To be honest,
I'm not even sure I have all the parts to this motor, as the whole
piano arrived in boxes, and all the parts weren't there to start with.
To the best of my knowledge, I have assembled the whole motor and it
is complete, but this is the first one I've seen.

Second, is there to be any play between the slide valve surfaces and
the surface of the motor face?  I have one slide valve that's snug,
but still slides freely, and two valves that have 1/32" or 3/64" play,
so they can rise up off the face of the motor and leak air unless the
vacuum is holding them down tightly.

The pouches are airtight.  I isolated each one and checked it under
pressure.  The slide valves are centered so that in each extreme of
their travel they uncover the same amount of hole.  The thing runs
smoothly when I hook it to an external source, but when treadling it
seems to gobble up air in huge quantities.

The ports which admit air are 1/2" diameter, the central port is closer
to 9/16.  Seems a little generous to me, but I don't want to mess with
changing it (by bushing the hole so it's a smaller opening) as it
appears to be original.

My frustration is that the motor appears very inefficient and is being
a vacuum hog, so that I can't continue on with the rest of the stack
regulation and debugging.  I hope somebody has some answers because
at the moment I'm ready to toss the motor completely, or just hook the
piano up to our Kirby.  (Just kidding, mostly.)

Thanks in advance.  Skip Downing, Lebanon, NH