Dan, look at the two 4.8 HP air motors, then look at the link. A torque motor and not much more than a ring and inner rotor with permanent magnets.Compressing air is one of the least efficient ways to store energy. As a former air-brake remanufacturer and troubleshooter, I can tell you about the terrific heat a compressor makes as the air is compressed. The Gas Laws of physics will tell us that when we reduce the volume of a given amount of a gas, its temperature and pressure will both rise. The heat is radiated and convected away from the compressor, its discharge lines, and the tank, and as the compressed air cools its pressure falls somewhat. When we use that compressed air its temperature falls enormously as the pressure is bled off, and this increases its density and reduces the effective pressure further.
The heat generated in air compression, along with the small amounts of lubricating oil that inevitably gets past the compressor's piston rings, causes coking in the head and discharge lines, evidence of serious heat. I have found heads and lines completely occluded by a coal-like material. Another problem with air compression is the condensation of atmospheric water vapor in the tanks as the air cools, causing corrosion and other problems with the air system, including freezeup in the winter.
The only real reasons for using compressed air include its ease of control and the fact that it doesn't make an oily mess everywhere if there's a leak.
The air vane motor acting as a compressor, if extended to an 18" diameter, would take on dimensions almost equal to the 18" torque motor disign. Just a little change of air intake and discharge ports, then enclose the setup and you have what would look a little like a pancake compressor tank.
The stator rings could turn with the top set of rotor blades and the rotors of the electric and air maker would turn opposit by the lower set of rotor blades.
Air would only be in the system from center intake to tip discharge.
I really can't comprehend why nobody seems to be able to see the simplicity here.
"No energy would be harmed in this process"
Torque motors do the trick | Machine Design