On Jun 17, 11:24*am, wrote:
How close to maximum speed are you running the motor?
Much less than 1/2 max speed, I think. I measured the voltage the
rheostat is outputting at my usual setting, and I was surprised to see
it was 104 V, with ~ 120 V input.
Ideally I'd have an inline sensor to measure air speed in the hose,
and if the air speed is outside a preset range, the sensor would raise
or lower the voltage.

Another solution may be a CPAP machine.

An airline respirator has a powerful motor for pushing air through a
long length of hose, unlike a CPAP machine.

Laura