Abstract: Two-phase voltage signals for use with a resolver-to-digital converter (RDC) are produced as a periodic function of permeance developed across an air gap between a rotor and stator wherein the permeance varies as a periodic sinusoidal function which can be related to the electrical angle of the position of the rotor. The two-phase voltage signals are developed as a function of inductive reactance and follow the form ##EQU1## wherein the phase angle between V.sub.x and V.sub.y is exactly 90.degree. and the term [A+A.sub.n +B+B.sub.n ] is completely free of second harmonics.

Abstract: A brushless D.C. motor drive circuit provides full available D.C. bus voltage to the motor during periods of motor speed acceleration and deceleration and modulated D.C. voltage to the motor during periods when no demands are made on the motor to accelerate or decelerate, thus avoiding time-lag problems inherent in the type of conventional brushless D.C. motor drive circuits which employ pulse-width modulators to continuously provide modulated D.C. voltage to the motor.

Abstract: A circuit for operating a brushless DC motor, the circuit receiving as inputs the positive/negative, or negative/positive DC power normally applied to reverse a brush-type DC motor, with the polarity of the input power determining direction of rotation of the motor. The input power is full-wave rectified to provide positive/negative DC power to the brushless DC motor drive. A polarity sense circuit determines the polarity of the input DC power and provides to the brushless DC motor drive a logic signal indicating commanded direction.

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.

Abstract: A method and means are provided for increasing the frequency of update of direction information contained in two essentially identical alternating current signals, essentially sinusoidal in waveform, and in quadrature. Eight electrical signals having rectangular waveforms are generated from the two primary signals. The eight signals are differentiated and the eight derivatives combined with the eight signals into two sets of eight additive pairs each, with a high level logic signal from one set indicating one direction and a high level logic signal from the other set indicating the opposite direction. The direction information is updated eight times during each full cycle of each of the two primary signals.

Abstract: An up/down counter interface converts input information suitable for the operation of one type up/down counter, which type receives input information in the form of a direct current logic signal indicating direction and a train of electric pulses representing increments of information, to input information suitable for the operation of a second type up/down counter, which second type receives input information in the form of two identical pulse trains representing increments of information, direction being determined by the relative displacement in time of the two pulse trains.

Abstract: The rotor in each of the disclosed stepping motors comprises a permanent magnet disc between toothed pole pieces, the diameter of the magnet disc is essentially equal to the outer diameter of the toothed pole pieces.

Abstract: A bobbin wound stepping motor has a stator formed of a plurality of stamped metal pieces that are concentrically secured together by projection welding through the use of an arbor except for its rear plate which is positioned concentrically by locating holes and half-blanks and secured in the assembled motor by push nuts after insertion of the rotor.

Abstract: Lead wires of a motor are stapled to a somewhat rigid, insulating disc to have their stripped ends be at selected points on the disc, the ends of the motor windings are placed in selected slots adjacent the stripped ends and wrapped thereabout and then soldered thereto to interconnect the winding ends with the appropriate lead wires, another insulating disc is positioned over the first and push nuts secure the assembly to the stator.

Abstract: The firing circuit serves to interface a load circuit including a semiconductor device capable of large load currents and a control circuit operating at logic power levels and provides a relatively low current output to the gate terminal of the semiconductor device, which may be a triac, for controlling the load circuit.

Abstract: A motor system having interchangeable modular components including a prime mover, a speed reduction unit, an output shaft and detachable electrical leads is disclosed. Various combinations of components easily may be mounted together to meet specific power input and output speed requirements as well as to provide various output shaft style configurations for driving connection with a driven member. The output shaft is releasably locked to the gear reduction unit and has means for coupling the output shaft to the output gearing.