Abstract: Method and means are disclosed for producing a D.C. signal proportional to the peak amplitude of an A.C. signal, which peak amplitude is proportional to the frequency of the A.C. signal. A second A.C. signal is generated from the first signal, having a frequency higher than that of the first signal and the second signal is rectified to produce an analog signal. The increase in frequency permits the subsequent processing of the analog signal in a high-frequency filter having a lower time-constant than would be possible were the analog signal produced directly by rectifying the first A.C. signal.

Abstract: An electric motor having a rotor and a stator with two sets of stator poles. The poles of one set of stator poles are disposed in positions about the stator which they would normally occupy if all stator poles were disposed symmetrically about the rotor. The poles of the other set are displaced from their normal positions by an angle. The angle is chosen so that a subharmonic of the fundamental torque/angle curve is substantially reduced, thus improving the performance of several types of motors.