High Power Electrostatic Motor 95% Efficency

[TinselKoala]

I agree that it is not a "high voltage" motor. That is my point, in fact: it cannot be, unless it uses a harder vacuum than is practicable considering the shaft seal, etc. Even then as you point out the clearances are tight, putting oppositely charged parts in close proximity.

However for there to be enough electrostatic attraction/repulsion to provide substantial torque I think the field strength must be pretty strong. Certainly small voltage differences acting over very small distances can result in high field strengths and steep gradients. I'd like to see the motor working, I just can't get a feel for how it could be so powerful and I can't imagine why a vacuum would be preferred over pressurization.

[mscoffman]

From my study of historical Wimshurst literature, being able to jump a spark gap of distance x implies
a more or less linear relation relationship with circuit voltage. This indicates to me that this motor's
input voltage will be in the range of vaccum-tube plate voltage; something  like 100VDC -> 1KVDC
or else it's pieces will arc to one another. One way to make some arcing self terminating would be
to operate the motor on a high voltage square wave (AC) input. This may be what is being heard in
the manufacture's web site videos. It may be that the motor operates to some extent on DC but needs
switched AC for full power.

I think the comment as to; "a vacuum operation" is most likely in reference to high-altitude and space
based operation in an unmodified open environment - which would need to be seen on the manufacture's
specification sheet BTW. Hopefully this motor will come with some sort of of plastic or metal enclosure
to keep loose parts or wires from falling into it.

:S:MarkSCoffman

[TinselKoala]

I've had a closer look at the description and diagrams of the motor on Revolution-Green. This motor is, I think, a commutated enhanced Franklin electrostatic motor. It works by exactly the same principle as my enhanced Franklin motor shown here:

http://www.youtube.com/watch?v=vqf3bUL4YqE

..... except it has optimised electrode geometry that doesn't waste most of the field like my simple "tub-motor" does. My motor is commutated by very small spark gaps between the balls and the primary field plates, whereas this motor apparently uses actual commutator and brush system at the armature just like an ordinary DC motor with stator and armature coils. As I suspected the motor doesn't produce a lot of torque and operates at very high RPM.
The motor design is also interesting in that it is very similar to the electrostatic generator I used in the video above, the Moore's Dirod, which will also operate as a motor if supplied with HV at its field plates. The Dirod's drum/rod assembly is doing just what the rotor does in the motor, and the Dirod's stator plates are doing what the stator rods are doing, and the Dirod is commutated by carbon fiber brushes, essentially wired in the same way as the motor's brushes.

So in response to mscoffman, the motor appears to be supplied with DC and does its own "chopping" by the commutation system. I imagine that it could also be controlled by supply PWM just like an ordinary DC brush-type motor.

Maybe it needs to operate in a vacuum because of the aerodynamic drag of all those rods on the rotor, spinning inside that cage of rods on the stator!!