Abstract: A capacitor motor and method is disclosed which utilizes one or more tap points within the auxiliary winding of the motor which can be selectively connectd to a source of AC power via a selector switch for multi-speed operation of the motor.

Abstract: A flat frequency, constant voltage power source device provided for parallel operation of a plurality of electric generators is arranged to have a starting sequence determination means which automatically determines which one of the electric generators is to be started initially and places the remaining ones of the electric generators sequentially into the parallel operation with the initially started generator, the plurality of the electric generators sequentially satisfying conditions for their parallel operation and being smoothly placed in parallel operation.

Abstract: This invention relates to a control system for an induction motor which has power factor control means for altering the power factor of the input current of a converter composed of self-arc extinguishing elements, such as transistors, to vary the d.c. output voltage of the converter to perform a pulse-amplitude modulation control in a variable voltage, variable frequency controller for controlling the rotating speed of the induction motor by the converter of a sinusoidal wave input to reduce noise generated by the operation of the motor.

Abstract: A method and apparatus for controlling the operation of an oil well pumping unit in which the prime mover is a polyphase AC electric motor. The system comprises means for generating a plurality of signals representative of motor fault parameters including a motor winding overtemperature fault, undervoltage fault, and a phase imbalance fault. Upon occurence of a fault, a contactor in the motor supply leads is open to shut down the motor. After such shutdown because of undervoltage or phase imbalance faults the fault parameters are continuously scanned and once the fault has been cleared the motor is restarted. Where motor shutdown occurs because of an over temperature fault, the motor is maintained in a latched off shut down condition until an operator implemented reset occurs. An accessible counting memory is provided having separate registers for each of the fault conditions.

Abstract: A method is described for controlling synchronous motor torque, utilizing a three-phase switch connected in a circuit to the input of a polyphase synchronous motor, and a switch control circuit. The switch control circuit senses the AC voltages input to the synchronous motor and produces signals that open and close the three-phase switch in phase with the input motor voltage, producing positive motor torque during normal operation. If input AC power is lost, the switch control circuit acts to prevent a reverse flow of high current from the motor from entering the power source bus. When input power, after a short time, returns, the switch control circuit acts to close the three-phase switch in such a manner as to permit only real power applied to the synchronous motor and thus positive torque that accelerates the motor speed and quickly restores the motor to synchronism with the input power source.

Abstract: In a circuit arrangement for operating a multiphase synchronous motor (10) on a direct current voltage main current valves (15-18), which are successively actuated via a ring counter (38), are connected in series with the phases (w.sub.1 -w.sub.4) of the armature winding (12) of the motor (10). A ring counter switching device (19) advances the ring counter (38) by pulses derived from the comparison of in voltages dropped across two blocked current valves (15-18). To restrict the self control range of the motor to an angular range which is much smaller than half a period, of the voltage drop decreasing in the course of time is additionally compared with a set voltage (k U.sub.S) by the ring counter switching device (19) and the ring counter advancement is enabled only for as long as this voltage drop is greater than the set voltage value.

Abstract: An electric motor has a rotor and a stator each of which is provided with a polyphase winding. The rotor and stator have the same number of poles but the number of phases in the winding of the rotor differs from that in the winding of the stator. The motor can operate as a stepping motor by deenergizing one of the phases of one winding while simultaneously energizing one of the phases of the other winding, and the motor advances one step whenever one phase of a winding is deenergized and, at the same time, one phase of the other winding is energized. The deenergizing and energizing steps are performed alternately for each winding. The motor can further operate as a synchronous motor by accelerating the motor, discontinuing the deenergizing and energizing steps for one of the windings while maintaining the excitation of such winding and, simultaneously with the discontinuing step, reducing the frequency of the deenergizing and energizing steps for the other winding.

Abstract: A power supply regenerating circuit according to the present invention is used in an inductor motor drive circuit which performs motor drive control and regenerative control. The induction motor drive circuit has a parallel circuit including a reverse connected diode (D10) and a resistor (R1) connected between a circuit (C2), which rectifies and then smoothes the induced electromotive force of an induction motor (M) during deceleration, and a bridge circuit (Tr1-Tr6) which effects a conversion into AC power. Regenerative power blocked by the diode (D10) is supplied to the bridge circuit (Tr1-Tr6) as a current limited by the resistor (R1), and the regenerative power is regenerated only during a predetermined interval of a three-phase period.

Abstract: Method of induction motor vector control in Cartesian and polar coordinates, whereby control of the rotor speed, induction motor torque, as well as dynamic, power, and thermal processes, which is interconnected with control of the rotor flux linkage amplitude and phase as functions of the desired induction motor torque, is achieved in an electric drive by synchronizing the stator current control by a controlled synchronization frequency by means of three control inputs, one control input is used to control the synchronization frequency and phase as functions of the desired rotor torque and speed; two other control inputs are used to control the amplitudes of ortho-phasal and current phase to a phase angle equal to the ratio of the ortho-phasal and co-phasal and ortho-phasal currents as functions of the desired induction motor torque, the actual desired amplitude of the rotor flux linkage, and magnetizing characteristic of the induction motor, while the amplitudes of the ortho-phasal and co-phasal currents is

Abstract: This invention relates to a method for controlling the torque of a synchronous machine supplied by a frequency converter, wherein starting from measured variables (i.sub.R, i.sub.S, i.sub.T, i.sub.f) representing the state of the machine the direct axis flux component (.psi..sub.d), the quadrature axis flux component (.psi..sub.q) and the pole angle (.delta.) for the machine are determined, and set values are produced for the flux (.psi. set value), excitation current (i.sub.fo set value) and current building the torque (i.sub.2 set value). To prevent the "pull out" of the drive in the method of the invention, from the determined pole angle (.delta.) there is formed, by means of a limiting block for the pole angle, a limited pole angle (.delta..sub.r) that equals the pole angle (.delta.) if the pole angle has an absolute value smaller than a separately adjustable limit (.delta..sub.max), but equals the limit (.delta..sub.max) if the pole angle has an absolute value equal to or greater than the limit (.delta..

Abstract: An inverter driving method for has an arrangement polyphase induction motor, for altering a plurality of winding connections of the motor and a storage arrangement for a plurality of motor control constant groups preset corresponding to the respective winding connections so as to perform optimal vector control. When the classification of the winding connection is selected, one set of motor control constant groups corresponding to the winding connection is read out of the storage arrangement and applied to a control unit of the induction motor as control constants.

Abstract: A controlling device for a permanent magnet synchronous motor wherein a permanent magnet is used as a rotor and which includes three-phase armature windings comprises a detecting means for detecting a rotational position and a rotational angle of said rotor, a comparison means for comparing the rotational speed detected by said cetecting means with a predetermined reference speed and for developing a value of a difference between the rotational speed and the reference speed, a converting means for determining currents to be supplied individually to said armature windings in response to a vector value obtained from the rotational position detected by said detecting means and the value of the difference delivered from said comparison means, and a current controlling means for controlling current flows through said individual armature windings in response to values obtained by said converting means.

Abstract: In apparatus for controlling the rotational speed of a synchronous motor arranged to be driven by an inverter having switches for selectively energizing respective windings of the motor, a current detector is provided to an input of the inverter for detecting input current to the inverter to thereby interrupt energization of the switches by using an output of a first timer circuit when the current exceeds a predetermined value, and a second timer circuit is provided for interrupting energization of the switches on switching between respective phases of the motor. An interrupting time duration by the second timer circuit may be varied in accordance with the rotational speed of the motor and by the plugging state thereof.

Abstract: A method and device are disclosed for braking a squirrel-cage motor in which the motor is controlled in a manner known per se by means of a voltage converter and a control circuit which switches off the main current to the motor in a braking situation, whereupon a direct current is supplied to the motor windings. To achieve a simple and inexpensive braking control system, the direct current fed into the motor windings is obtained from a rectifier bridge formed in the braking situation via electrical control from certain semiconductor components of the voltage converter.

Abstract: The properties synchronous motors are provided to an asynchronous motor fed with the aid of a digital speed control via a static converter. For this purpose, a signal proportional to an integral of the rotation-speed deviation, and a signal corresponding to the rotation-speed set-point value, are multiplied with each other and therefrom is obtained the control-pulse sequence for the converter. From an input sequence corresponding to the measured rotation speed, a signal corresponding to the period duration of the rotation-speed measurement-device frequency is obtained, and this signal is divided by a value corresponding to the rotation-speed set-point value. The period-duration signal referring to the rotation-speed set-point value thus obtained is switched opposite to the control-deviation signal, before the control-deviation signal is fed to the multiplier.

Abstract: In order to feed to the converter on the load side of an intermediate-link frequency converter a frequency control signal (fI(S)*) which is formed by means of an angle controller (RW) from the difference of an angle reference value (wi(F)*) and a corresponding actual value (wI(F)), an actual value of the phase current is required which, for stable operation, must not contain heavy harmonics in stable operation nor must not be damped excessively dynamically by smoothing. Therefore, the measured actual angle value (wI(S)) is fed as the reference value of a servo controller (RS), to the output of which the integral (wI(S)*) of the frequency control quantity is added and the output of which is fed back to the input of the servo controller (RS).

Abstract: An electrical machine driven by a pulse-controlled a.c. converter contains multiple phases subdivided into a number of n.gtoreq.2 equivalent phases sections that are extensively magnetically decoupled relative to each other. Each phase section is fed by a separate frequency converter. The clocking of the frequency converters for the n phase sections ensues out of phase by an angle of 2.pi./n relative to each other phase section.

Abstract: To reduce harmonics in an induction machine (33) which is fed by a self-commutated inverter (30), the trajectory of the flux vector of the induction machine is conducted along an edge path having at least 2.sup.p .multidot.q.multidot.m edges, where p is an integral number .gtoreq.1, q.gtoreq.2 is the number of voltage stages of the inverter and m.gtoreq.2 is the number of phases of the induction machine. In this arrangement, the flux vector is alternatingly conducted along straight and zig-zag segments. This reduction is essentially achieved by means of at least one second flux conducting circuit having a second coordinate con=verter (56) and a second comparator (57) in addition to a first flux conducting circuit having a first coordinate converter (54) and first comparator (46), the flux components (.psi..sub..beta.1' -.psi..sub..beta.3') at the output of the second coordinate converter being shifted by 30.degree. in phase with respect to the flux components (.psi..sub..beta.1 -.psi..sub..beta.

Abstract: A method and circuit for application in a PMW inverter for controlling power to an AC motor in which a hysteresis modulator is employed as a current limiter to override sine-triangle modulation in a PWM generator circuit. When the magnitude of motor current reaches a hysteresis band upper limit, the hysteresis modulator generates a large limit current to a summing input on a current regulator which feeds the PWM generator to override and mask out the normal sine-triangle modulated signal. When the magnitude of motor current decreases to a hysteresis band lower limit, the limit current is terminated, and the sine-triangle modulation is resumed.

Abstract: For connecting the d-c terminals of a voltage-source inverter to a direct current (d-c) power source, a d-c link capacitor is connected directly between the d-c terminals, a line capacitor is connected in parallel with the d-c link capacitor, and a series inductor is connected between the line capacitor and the source. A dynamic brake resistor and an electric power chopper are connected in series with one another across the line capacitor. Between the two capacitors, no inductance is provided but a resistor is inserted in the braking current path during electrical braking operation of the inverter.