Abstract: A star-connected sensing resistor at the A.C. output side of a PWM inverter detects an output voltage across the resistor, a PWM control according to the invention then amplifies the detected voltage, compares the amplified voltage with a sine wave voltage command signal, amplifies the compared output in a P-I amplifier having a definite gain for a D.C. current, compares the P-I amplified output to a carrier and thus provides a PWM output for controlling the inverter.

Abstract: There is provided a motor having a frequency generator comprising a frequency generating base plate on which a frequency generating coil pattern and a land are formed, in which a signal of the frequency proportional to the rotational speed of a rotary driving apparatus which is generated from the frequency generating coil pattern is output from the land to another base plate. The land is formed in the frequency generating coil pattern.

Abstract: A synchronous rectifier is able to operate at higher frequencies and provides an output having lower noise than prior art FET synchronous rectifier system by using field effect switching devices which contain only one conductivity type of semiconductor material and connecting a high speed, low charge storage diode in parallel. Schottky diodes are preferred whereby there is no junction diode in the structure. Conventional FETs may be used when paralleled with a Schottky diode which prevents the FET's parasitic internal diode from becoming conductive.

Abstract: A pulse width modulated inductive load controller including a load switching circuit having a plurality of switches which are operative in pairs; each pair including first and second switch devices for controlling power to a load. Commutation logic enables various sequential combination of pairs of switch devices and a clock defines the operation period of each sequential combination of switch device pairs. Pulse width modulation circuitry controls the closed time interval of the switch devices during the operation period of each combination of switch device pairs. Transition control circuitry maintains closed at least one of the switch devices in each sequential combination of switch device pairs after the other switch device is opened, thereby assuring that any regenerated current from the previously energized load coils is provided a path to recirculate through the load.

Abstract: A reactive power controller for a reactive power output from a self-commutated inverter connected to an AC system power source via an AC reactor, the inverter alternatively acting as a capacitor or a reactor, in which an operating unit produces a DC reference voltage for the inverter from a reactive power reference signal and a system power voltage. A differential operation device produces a phase difference angle for the inverter, in which a phase controller outputs firing pulses for controllable rectifier elements of the inverter according to the phase difference angle. An output AC voltage of the inverter is controlled by varying a supply of an active power from the inverter or the system power source to the latter or the former according to the phase difference angle so that the DC voltage of the inverter may be equal to the DC reference voltage.

Abstract: A drive unit for direct drive of an information-storage disk comprises a brushless dc external-rotor motor having a permanent-magnet rotor magnet arrangement of considerably reduced axial length. Electrostatic charge is removed from the rotor shaft by a metallic spring element which engages the shaft periphery from within the interior of the rotor housing. An electromagnetic braking arrangement is located interiorly of the housing. The packet of stator plates for the stator has an axial length shorter than that of the rotor magnet arrangement, but is provided at its axial end faces with skirted-rim flux-conducting elements whose peripheral skirt portions form useful-air-gap extensions in cooperation with the rotor magnet arrangement.

Abstract: A dc commutator motor can be switched off when the motor rotor is short-circuited by the rotor's coming to a halt, by an operating switch (10). The switch is provided in the line connecting the brushes to a radio suppression network in a compact and simple design. The switch is operated by an ac voltage induced when the motor is running, with a frequency corresponding to the motor speed. A sensing winding connected to the operating switch for inducing the operating ac voltage is wound preferably around a radio interference suppression choke of the radio suppression network.

Abstract: A D.C. motor is provided with a higher sustaining torque by providing an ascially extending slot on each tooth of an armature core. The slot is located in the center of the outer surface of each tooth opposite the field magnets.

Abstract: A fan drive and water slinger seal for a vertically mounted electrical motor. A fan is placed on a motor shaft so opposing flats on the interior surface of the fan hub fan mater with corresponding flats on the shaft to prevent slippage between the fan and shaft during motor operation. The hub contains a spring like finger extending upward axially along a groove in the inner wall of the hub and engaging an annular groove on the shaft to prevent axial movement of the fan along the shaft. The fan is positioned between a motor endshield and an overlying drip pan which encircles the shaft and carries liquid away from the motor. A flexible slinger snugly and adheringly fits on the shaft and has an O-ring type interior seal for sealing within a second annular groove on the motor shaft.

Abstract: A power source control system for controlling a power source of a terminal device, including a timer in which an actuation time is preset and a control circuit which receives a signal from the timer. At the actuation time, the timer outputs the signal to the control circuit such that the control circuit performs on-off control of the power source of the terminal device.

Abstract: A plug-in power supply includes a housing dimensioned to fit into a space designed to accept a circuit breaker in a load center to provide D.C. power from an A.C. main power. The housing encloses a circuit card that has components that are connected between A.C. inlet terminals and D.C. output terminals to provide a peak current for a short duration, limit the output to a D.C. voltage maximum, and interrupt the output current when the output voltage drops below a certain level.

Abstract: A motor for rotating a magnetic disk, an optical disk, or a magneto-optical disk comprises an armature concentrically secured to a center shaft affixed to the base frame of a disk drive unit. A rotor frame is rotatably supported in a cantilever fashion on a free end of the center shaft by a pair of bearings. The rotor frame is cup-shaped with a depending cylindrical sidewall encircling the outer peripheral surface of the armature. The sidewall includes a disk support that projects outwardly from the sidewall. A permanent magnet secured inside the sidewall interacts with magnetic fields produced by the armature. The cantilever support makes it easier to bring armature leads through a hole in the mounting frame as a part of the manufacturing process.In an alternate embodiment, the center shaft is shortened so that the lower bearing on the shaft rests upon the frame. The cup-shaped rotor is mounted on the bearings with a hub having a depending cylindrical wall mounted on the lower bearing.

Abstract: A PWM (pulse width modulation) inverter generating an a.c. output having a variable voltage and a variable frequency supplies a.c. power to a linear induction motor. An electric car supported by wheels is driven by a driving torque produced by the linear induction motor. While the electric car is running, the motor torque varies due to various factors among which a variation of the air gap length is representative. The power factor cos .phi. of the PWM inverter is detected to calculate the motor torque, and the output voltage of the PWM inverter is regulated or mechanical brakes are controlled so as to compensate the torque variation. Thus, the variation of the air gap length, which is representative of the factors giving rise to torque variations and which has been difficult to be detected, can be reliably detected to permit torque control according to the torque variation of the linear induction motor.

Abstract: An electric actuating bolt motor with a gear unit for use in a motor vehicle, the motor including a shaft rotatably supported in a motor housing and a toothed part arranged externally of the housing, and further including a bearing shield, an attachment flange and an aperture side wall which embraces the toothed part, the bearing shield also having an end wall in whose region a bearing area for the shaft is provided. The bearing shield prevents damage to the shaft and the toothed part of the actuating motor prior to its assembly with the gear unit.

Abstract: A magnetic frequency triplo-multiplier for use as a power source for metal melting furnaces and the like. The frequency triplo-multiplier has Y-connected primary windings that are resonant with each phase of a three-phase alternating-current power source and serially-connected secondary windings that are resonant with a triple frequency so as to produce a large single-phase power. The frequency triplo-multiplier uses a five-legged iron core, and capacitors connected in parallel with first, third and fifth leg windings of the five-legged iron core to bring about resonance with the three-phase alternating-current power source, while second and fourth leg windings of the five-legged iron core are connected in series and shunted by a capacitor so as to bring about resonance with a triple frequency.

Abstract: In a generator exciter composed of a stator (12) for producing a dc field and a rotor (16, 18) mounted to rotate relative to the stator (12) and including armature windings (18) connected to generate ac output currents, the rotor (16, 18) is mounted radially outwardly of the stator (12), and is insulated from its support.

Abstract: A lightweight electromotive device with a high power-to-weight ratio capable of operating as an efficient motor, alternator or generator includes an mangetic-flux producing assembly comprising spaced magnetic elements, and an armature assembly formed by winding conductive, non-magnetic wire, such as copper wire on flux carrying core or stator bar elements. The elements are shaped to form an eddy current shield for the windings and provide two heat radiating surfaces. This allows the device to operate with minimal eddy current losses and maximum radiation and convection cooling. The armature windings and flux carrying elements are dispersed as a further measure to avoid creating opposing induced currents.

Abstract: A system for regulating the operating point of a direct current power supply comprising a current generator system connected to a pulse width modulation converter includes a circuit for sampling and measuring the voltage and the current supplied by the current generator. A threshold detector circuit responding to stalling of the converter supplies a logic signal representing the stalled or non-stalled state of the converter relative to threshold values. A regulation loop includes a switching device for inverting the sign of the error signal so that the operating point can be moved towards the maximum power point on the output current-voltage characteristic of the current generator. The system is applicable to regulation of the electrical power supply circuits of spacecraft, space probes, satellites and the like.

Abstract: The present invention relates to a 3-position rotational actuator which obtains three stable points by two pairs of field poles, in which the magnetic flux to a rotor due to one pair of field poles of a stator for maintaining the rotor at the first stable point is substantially equal to the magnetic flux to the rotor due to the other pair of field poles of the stator for rotating the rotor from the first stable point. The magnetic flux density of the other pair of field poles of the stator applied to the rotor is set to be smaller than the magnetic flux density of the one pair of field poles of the stator. Therefore, the detention torque can be maintained to the same degree and the drive torque can be improved.

Abstract: A series voltage regulator includes a protective circuit that detects the collector current from a PBP power transistor and the collector-emitter voltage thereof. Such current and voltage signals are generated, respectively, by an auxiliary PNP transistor having a collector current which is proportional to that of the PNP power transistor, and by a circuit connected between the emitter and the collector of the PNP power transistor. The collector current and collector emitter voltage signals are processed by a circuit which, whenever the current and voltage values are greater than preset maximum values, reduces the PNP power transistor current and maintains it within permissible limits. The protective circuit does not affect the minimum voltage drop between the input and output of the regulator and may be dimensioned so as to use the maximum extent of the S.O.A. of the PNP power transistor.