Abstract: An improved conductor for an inductor device of the type having varying current carrying requirements along the length of the conductor, the improvement comprising having the conductor contoured such that the cross sectional area of the conductor varies substantially directly as the current carrying requirements of the conductor vary. In one embodiment, a coil for a variable transformer is cut from a cylinder of conductor material by numerically controlled machining, producing a contoured conductor and eliminating the requirement for coiling or winding of the conductor.

Abstract: A high torque-to-low mass variable reluctance motor includes a cylindrical stator assembly having a plurality of stator segments circumaxially arranged about a rotor wherein adjacent stator segments are maintained in a spaced apart relation with one another by non-magnetic pins which provide a radially inwardly projecting channel extending fully from the outer circumference to the inner circumference of the stator assembly to essentially magnetically isolate the stator segments from one another. A generally annular, non-magnetic shell coaxially surrounds and engages the outer periphery of the circular stator assembly to cause a compressive force to be directed radially inwardly to maintain the stator segments in a precisely aligned arrangement.

Abstract: A stator for electrodynamic machines provides for more efficient design by reducing the total number of stator legs required for two-speed, two-phase motors and for generators producing electrical power at either of two frequencies while operating at a constant speed. This is accomplished by external switching, so that at one condition, all coils on all stator legs are energized in the normal symmetrical pattern, while at the other condition, all coils on all stator legs are energized in a non-symmetrical pattern.

Abstract: A method for making an improved conductor for an inductor device of the type having varying current carrying requirements along the length of the conductor, the improvement comprising having the conductor contoured such that the cross-sectional area of the conductor varies substantially directly as the current carrying requirements of the conductor vary. In one embodiment, a coil for a variable transformer is cut from a cylinder of conductor material by numerically controlled machining, producing a contoured conductor and eliminating the requirement for coiling or winding of the conductor. A brush guide groove may also be provided in the conductor.

Abstract: Apparatus for controlling torque and torque ripple in a variable reluctance motor uses a generated torque waveform for each phase of the number of phases associated with the motor and corresponds to an electrical current having a predetermined constant magnitude. The generated torque waveforms are utilized to provide a table of values representative of the electrical current magnitude at each of a number of sensed rotor angular positions. The values correspond to the torque produced by the motor when excited by an electric current having that value and the location of the value in a memory device are defined by the sensed angular position of the rotor and a desired torque command signal. Depending on the torque to be produced by the motor and the rotor position, the motor is excited with the value of current selected for one or a combination of phases to cause the motor to develop a desired torque which has a substantially flat and ripple-free response characteristic.

Abstract: A magnetic rotary encoder system includes a magnetoresistive sensor having a magnetoresistive element array which is selectively connected to accommodate a number of different diameter encoder wheels each wheel of which contains a different number of pieces of magnetic information recorded at corresponding different wavelengths. A sensing and conditioning circuit is coupled to the magnetoresistive sensor and detects changes in resistance of the magnetoresistive elements when a magnetic field produced by a magnetic pole causes the magnetoresistive resistance to drop. Output signals are provided in quadrature to increase the resolution of the system.

Abstract: A magnetoresistive sensor includes groups of MR elements arranged on a non-magnetic substrate for selective connection to detect and sense magnetic information recorded on a number of different diameter encoder wheels of which each diameter wheel may have a different number of pieces of magnetic information recorded at corresponding different wavelenths (.lambda.) on a circumferentially running track located on the circumferential face of the wheel. The MR sensor includes an additional MR element arrangement for detecting and sensing index magnetic information recorded on an additional circumferentially running track located on the circumferential face of the wheel.

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 three-phase stepping motor having magnetically interacting stationary and moving members, the stationary member having first, second, and third sets of stator poles, each stator pole having thereon a coil for magnetic energization thereof. The coils on the first set of stator poles and one-half of the coils on the third set of stator poles are connected to one phase of a two-phase drive. The coils on the second set of stator poles and the other half of the coils on the third set of stator poles are connected to the other phase of a two-phase drive. The fluxes produced by the currents of the two drive phases are, in effect, magnetically combined in the moving member, as if the third set of poles wewre energized by a "third phase". In one embodiment, a twelve-pole, rotary, three-phase stepping motor with a 50-tooth rotor and a 48-, 50-, 52-, or variable-tooth-pitch stator produces a step angle of 1.8.degree. mechanical with a two-phase drive.

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: An electromagnetic machine of the type having a moving member and a stationary member, with a set of structures on the moving member to magnetically interact with a set of structures on the stationary member, has an improved construction comprising displacing by an angle of displacement, .alpha..sub.m, from their normal positions, a first portion of one set of structures whereby the displacement causes a harmonic of the fundamental torque/angle curve to be attenuated. The angle of displacement is determined by the following relationship:.alpha..sub.m =.alpha..sub.e /p,where.alpha..sub.e =displacement in electrical degrees,p=number of moving member magnetic pole pairs,further where .alpha..sub.e =180/h,where h=an integer equal to the number of a harmonic of the fundamental torque/angle curve to be attenuated.

Abstract: The pole members of each phase of a synchro have quadrifilar windings wherein each conductor is wound over six poles associated with a given phase. A voltage signal from an alternating current source is impressed across one conductor from each phase connected in series. The remaining conductors are connected to produce resolver-based Rsin.theta. and Rcos.theta. signals directly from the synchro without conversion from the normal three 120.degree. out-of-phase signals.

Abstract: A three-phase stepping motor having first, second, and third sets of stator poles, with the first and second sets of stator poles having single coils thereon and the third set having dual or bifilar coils thereon. The coils on the first set of stator poles and one of the coils on each pole of the third set of stator poles are connected to one phase of a two-phase drive. The coils on the second set of stator poles and the other of the coils on each pole of the third set of stator poles are connected to the other phase of a two-phase drive. The currents of the two drive phases are thus magnetically combined in the third set of stator poles to produce energization of the "third phase". In one embodiment, a twelve-pole, rotary, three-phase stepping motor with a 50-tooth rotor and a 48- , 50-, or 52-tooth-pitch stator produces a step angle of 1.8.degree. mechanical with a two-phase drive.

Abstract: A physically programmable electrical connector 70 has a first plurality of interconnected conductive paths 71-78. A second plurality of conductors 103-110 and a third plurality of leads 71'-78' are connected to the conductive paths. Electrical discontinuities 87-97 are selectively established in some of the conductive paths, such that the conductors become electrically connected to the leads in a predetermined pattern. A single connector design may be used for connecting varying numbers of conductors and leads.

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: A mid-range stabilization circuit for use in a multiphase stepping motor control system having motor current controllers responsive to first and second reference signal inputs, the current controllers providing a level of current to the motor phases proportional to the reference signals. The stabilization circuit includes means for measuring the levels of the reference signals and means for limiting the levels of the reference signals such that the motor current controllers can provide current chopping when the motor is operating at a mid-range velocity.

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.