My thanks to all those who responded to my query regarding a suction
source for a reed organ.  All the answers raise in my mind another
issue regarding what is the difference in basic design of electric
suction units for organs or for pianos

I have a Lee unit which has a simple 9" diameter radial blade with
straight fins perpendicular to the shaft (similar to a simple paddle
wheel).  It uses a 1/2 hp 3450 rpm motor.  When running at a slightly
reduced voltage the unit will produce about 3.5 inches of vacuum (no
load conditions). When the organ is running full bore (say 6 notes
playing on 6 ranks), the vacuum is reduced to only 3.2 inches. It thus
appears practical to use this blower without reservoir or regulator.

If I use a player piano/vacuum cleaner type unit I can use a voltage
regulator and air bleed to give me 3.5 inches of vacuum under no load
conditions.  When however I run the organ under full bore conditions as
above the suction level will drop to below 2 inches.  Some sort of
regulator in this scenario would seem desirable.  This large drop seems
inherent because the characteristics of the vacuum cleaner type turbine.

Most of the responses to me suggest using a player piano type turbine.
It seems to me however, that I will have a much more stable vacuum
source if I use a paddle wheel type radial fan system.

Any further comments ?

Phil Dayson