A 1-phase 48-pole axial peg style electrostatic rotating machine utilizing variable elastance

Starting from the duality of magnetic reluctance and electric elastance, this paper discusses design features of an axial peg style electrostatic rotating machine. Axial peg style refers to the geometry of the machine. Interdigitated pegs (cylinders) come into, and out of, radial alignment as the machine rotates causing variable capacitance between the stator and rotor. A prototype with peak torque of 0.9 N-m and gap field strength of 14 kV/mm was constructed. The specific torque density of the machine is 0.126 N-m/kg, comparable to fractional horsepower NEMA class induction machines. This was achieved by filling the machine with a dielectric fluid whose relative permittivity is 7.1, rather than ultra-high vacuum typically employed in canonical macro scale electrostatic machine designs. Selected experimental measurements presented include angular capacitance, stall torque, average torque and losses under stall conditions.