Abstract: A control system for poly-phase power inverters that uses feedback sensed voltages and currents to control the switching of solid state power switches in the inverter bridges, producing a nearly ideal sinewave voltage output regardless of load induced or switching harmonic voltages. The system operates in combination with the inverter power switches and switch drivers, particularly incorporating a digital programed optimal controller with virtually no delay in implementing the feedback control, and automatically correcting for any sensed line voltage distortions. The system inherently provides a high recovery speed for voltage transients.

Abstract: A method for controlling a power converter and an associated auxiliary commutation circuit ensures soft-switching of all switching devices employed therein. Such a power converter includes an inverter with at least two main switching devices per phase. Across each main switching device are connected an antiparallel diode and a relatively large snubber capacitor. The auxiliary resonant commutation circuit comprises two antiparallel-coupled auxiliary switching devices coupled in series with a resonant circuit including an inductor and the snubber capacitors. The gating and conduction times of the main and auxiliary switching devices are controlled so as to add boosting energy to the resonant operation, thus ensuring that the inverter output voltage at least reaches the positive and negative inverter rail voltages during each resonant commutation cycle. As a result, the control achieves commutation of the converter pole with substantially no switching losses.

Abstract: In a PWM control type power supply apparatus, a modulation (high frequency) signal component is eliminated from an AC output.

Abstract: A noncontact magnetic bearing has cylindrical magnetic members magnetized axially, slightly different in radius and different in length, disposed in opposite relation to each other, with their magnetic poles of reverse polarities displaced vertically relative to each other. Either the inner cylindrical magnetic member or the outer cylindrical magnetic member can be used as a shaft, and consequently, the other is fixed to a support member. The inner cylindrical magnetic member and the other cylindrical magnetic member are held at a stable and mutual-noncontact state to provide a noncontact magnetic bearing that is stable axially, as well as radially.

Abstract: A built-up stepping motor includes upper and lower housings each having an internal space and joined together with a support plate disposed therebetween. The lower housing retains therein a stator and a rotor disposed in the stator, while the upper housing holds therein a reduction gear for reducing the output speed of the motor. The output end of a rotor shaft extends through the support plate and meshes with a first gear of the reduction gear. The upper and lower housings are assembled together by interlocking engagement between locking projections and mating holes. A shock-absorbing damper is disposed between two stator cores to protect them against chattering.

Abstract: A construction of an electric induction motor having a stacked stator core (10) arranged around the outer circumference of a rotatable rotor (12) via an annular air gap (14), front and rear housings (20 and 22) arranged at front and rear ends of the stator core (10) and supporting the rotatable rotor (121) via rotary bearings (24 and 26), and mounting legs (28) separate from the front and rear housings (20 and 22). The stacked stator core (10) is formed, at a periphery, with through-bores (32) permitting tie-bolts (30) to pass therethrough, to thereby combine the front and rear housings (20 and 22) and the stator core (10) together as one body. The separately formed mounting legs (28) are fixed to the front and rear housings (20 and 22) by bolts.

Abstract: A drive system for a pump/compressor which feeds a pneumatic circuit of a portable waste water sampling device, and comprising individual electric motors (20) each operating at 12 volts and drawing a current no greater the 350 mA at 2.5 w, the motors driving a common pinion (23) with an output shaft (24) for connection to the pump/compressor. The use of a number of low capacity drive motors, which together provide sufficient torque to drive the pump/compressor, avoids the danger of spark generation, particularly in a potentially explosive environment such as may be found below ground. Since the motors are small they may be mounted conveniently within the sampling equipment, taking up no more space than would be occupied by a single motor of larger capacity.

Abstract: A switched mode power supply circuit includes a controllable switch for controlling the current in the supply transformer of the power supply circuit. During normal operation of the power supply, its DC output voltage is maintained at a substantially constant, first value in spite of variations of the DC input voltage and of the load on the output voltage by controlling the duration of the conductivity time of the switch. A function generator supplies a signal, which is a given function of the output voltage, to a control input of a pulse duration modulator for determining the duration of the conductivity time. At an output voltage which is considerably lower than the first value, the signal of a starting circuit is passed on by a selection circuit to the said control input in order to increase the conductivity time of the switch. This signal corresponds to a shorter switch conductivity time than does the signal of the function generator.

Abstract: An electrical power converter including both DC and AC power terminals which are respectively connected to a DC current source and an AC voltage source, the latter comprising the grid of an AC power utility. A capacitor is coupled to the AC terminals along with a load. A control and gating circuit is coupled to the converter for supplying control signals for the thyristors of a converter bridge included in the polyphase converter. When disconnected from the utility grid, a relatively fast acting control loop is coupled to the control and gating circuit and is responsive to the current flowing in the capacitor and an AC reference voltage to accommodate the current source characteristics of the converter for maintaining an output voltage of substantially constant amplitude across the AC terminals.

Abstract: An electrical circuit receives an alternating input signal and full-wave rectifies the alternating input signal. The rectified signal is then developed by the circuit into an output signal which has a frequency double the frequency of the alternating input signal. The doubled-frequency output signal is then output to a load. Alternatively, the circuit receives a direct current input signal, converts the direct current input signal into a periodically varying output signal, and outputs the periodically varying output signal to a load.

Abstract: An induction generator is disclosed wherein both the stator and rotor windings are utilized to generate power with the three phase winding of the stator and rotor each connected in parallel with a delta connected capacitive network connected therebetween. The electrical output may thus be increased by a factor of four over a conventional generator of the same size.

Abstract: Disclosed herein is a swing-arm type linear d.c. brushless motor, wherein at least one coreless type armature coil such as an air-core armature coil is arranged on the inner wall of a linear motor body and a field magnet is formed by magnetizing a magnet member with a single pair of N/S poles so as to permit the generation of thrust in a predetermined direction face to face with only one active conductor of said at least one armature coil and which does not contribute to the generation of reverse thrust. The field magnet is opposite through an air-gap in the axial direction to only the active conductor portion, and is supported relatively and swingably through the air-gap. It is suitable for use in small, economical and high-speed magnetic head positioner mechanisms more useful in small-capacity magnetic disk units and the like and capable of performing position detecting, feed control, etc.

Abstract: An actuator has a permanent magnet ring with a plurality of radially magnetized poles rotatably positioned between a pair of toothed pole pieces with interdigitated teeth, an electromagnetic coil and pole elements coupling the coil flux to the pole pieces. The pole pieces may themselves be rotatable or stationary. The permanent magnet circuit attempts to move the magnet ring to a first position relative to the pole pieces, and the electromagnetic circuit, depending on the direction of current in the coil, torques the magnet in one direction or another toward stable positions on either side of the first position. The device is used as a two or three position actuator or as an actuator operating against an external force and seeking a position as a function of current.

Abstract: An improvement is provided for a circuit having a first winding of N.sub.1 turns connected in series with a total inductance of L across a first voltage V.sub.1 and a second steering winding of N.sub.2 turns connected in series with a total inductance L.sub.2 across a second voltage V.sub.2 with the second winding magnetically coupled to the first winding and the first winding having an inductance L.sub.c produced by the N.sub.1 turns as seen across the first winding comprising L.sub.1 set substantially greater to zero and L.sub.2 set substantially equal to (L.sub.c) (N.sub.2 /N.sub.1).sup.2 ((V.sub.2 /V.sub.1) (N.sub.1 /N.sub.2)-1)). The setting of L.sub.1 and the setting of L.sub.2 providing an improvement to reduce ac ripple current.

Abstract: A double swing power unit for use in a plasma nuclear fusion experimental system comprising a bias bank, a bias switch provided by a semiconductor switch element having a rectifying function, a decoupling inductor, and a load coil connected in series, a series connection of a reverse switch and a reverse bank and a series connection of a hold switch and a hold bank, both thereof being connected in parallel with the load coil, and a control switch connected in parallel with the bias switch.

Abstract: Current sharing between paralleled power converters is attained by adjusting the error signal in the converters regulation circuit to assure that all the paralleled converters have a regulated output voltage that forces the converters to share the load equally. In particular circuitry is provided to limit the variation in output voltage that can be achieved through operation of the current sharing control.

Abstract: A power supply for converting a variable DC input potential (12) to a regulated DC output potential in accordance with the invention includes a plurality of DC to DC converters (300), each converter operating in response to a DC input potential having an operating range, having an input for receiving a DC input potential which is variable in magnitude, and an output for producing the DC output potential, the outputs of the converters being coupled together; a variable voltage divider (18) having an input coupled to the variable input potential, a plurality of connected stages (100) coupled to the input potential, at least one control signal applied to the variable voltage divider for controlling a number of stages across which the variable input potential is dropped; a switching circuit (200), coupled between the variable voltage divider and the plurality of DC to DC converters, responsive to at least one switching control signal, for coupling an output potential developed by at least one of the stages to at

Abstract: A PWM converter apparatus having phase detection means including an error detection protection device for outputting an estimate value as a present phase signal when a phase signal in each computation cycle deviates for a predetermined value or more from the estimate value obtained according to the former phase signal, the frequency of a power voltage, and a computation cycle.

Abstract: A permanent magnet rotor for an electric motor includes longitudinally extending main rotor field and sensor field sections, the sensor field section being substantially shorter than the main rotor field section and being disposed at one end thereof. The sensor field section is magnetized in circumferentially disposed parallel strips of alternating magnetic polarity around the rotor. The main rotor field section has longitudinally extending strips of alternating magnetic polarity which are skewed in a predetermined pattern. The predetermined pattern includes a first portion in which each longitudinally extending strip runs generally at a first predetermined non-zero angle with respect to the longitudinal axis of the rotor, a second portion in which each longitudinally extending strip runs generally at a second predetermined non-zero angle with respect that axis, and a third portion in which each longitudinally extending strip runs generally at the first predetermined non-zero angle with respect to the axis.

Abstract: A voltage multiplier circuit of the present invention includes a first power supply line, an oscillator circuit connected to the first power supply line, a serial circuit composed of an inverter for receiving the output of the oscillator circuit, the first capacitor for receiving the output of the inverter and the first and the second diodes, an output circuit and a second capacitor both connected to the output of the serial circuit, a third capacitor connected between the input terminal of the inverter, and the connection point of the first and the second diodes, a first Zener diode connected between the connection point of the first capacitor and the first diode, and the second power supply, a second Zener diode connected between the second power supply line, and the connection point of the first and the second diode, a third Zener diode connected between the first and the second power supply lines, and a fourth Zener diode connected between the second power supply line and the third power supply line conne