Electrical motor controls including non-linear series resonant circuits

Claim 1

In a rotary electrical machine having a rotor and N stator windings, a high speed contactless commutator for energizing the stator windings in sequence from a source of direct potential, which comprises: N normally disabled gates individually connected between the stator windings and the potential source; N nonlinear series resonant circuits each including a saturable core reactor, a capacitor, and a noncapacitive impedance; an oscillator; means for connecting the oscillator in parallel with each of the series circuits; means individually coupling the voltage across the noncapacitive impedances in the series circuits respectively to the gates for enabling each gate when a voltage pulse appears across the associated noncapacitive impedance; a magnetic member coupled to the rotor for rotation therewith; and means for mounting the N saturable-core reactors at equal angular intervals around the rotor axis adjacent and in magnetically coupled relation to the magnetic member so that the member rotates past the reactors in sequence during each cycle of rotation of the rotor, the movement of the member past each reactor causing a gate-enabling voltage pulse to appear across the associated noncapacitive impedance of the series circuit.