Abstract: An apparatus for controlling an A-C powered induction motor for an elevator cage, said apparatus comprising a rectifier for converting 3-phase A-C power into D-C electric power, an inverter connected to the rectifier for converting the D-C power into A-C power of variable voltage and variable frequency, a current detector connected to detect input current of the inverter, a power detector for detecting power supplied to the inverter based upon an output of the current detector, a control unit for generating a command signal to control the inverter in accordance with slip of the induction motor as determined by the power supplied to the inverter, and a correcting unit operable responsive to the power detected by the power detector for correcting the slip of the motor to maintain the power supplied to the inverter at predetermined values.

Abstract: An induction motor system, including a housing, a stator supported by the housing and having a plurality of stator winding conductors positioned about an axis of rotation, and a rotor mounted in the housing for rotation about the axis of rotation, is provided with an integral electronic controller for dynamically and programmably controlling the currents supplied to individual conductors of the stator winding. The stator winding conductors are connected in common at one end and are individually connected to a switching circuit at the other end. The switching circuit supplies positive or negative current pulses through selected conductors. Pulse width modulated signals generated by the controller simulate sine wave energizing signals to provide various operating configurations. By programmed variation of the fundamental frequency, pole configuration, phasing and power level, the rotating speed, starting, acceleration, torque, reversing, dynamic braking and efficiency are dynamically controlled.

Abstract: A control apparatus for an escalator wherein a low speed operation is performed in the absence of passengers at the escalator, and a high speed operation is performed in the presence of passengers at the escalator the alternating current of a three-phase A-C power source is converted by frequency conversion means into a three-phase alternating current of low frequency, with which an induction motor is energized to perform the low speed operation, so that the induction motor is rotated near a synchronous speed corresponding to the low frequency, to realize the low speed operation of high efficiency.Moreover, when passengers have been detected, the frequency of the alternating current from the conversion means is gradually raised, and the conversion means is thereafter switched to the three-phase A-C power source upon detecting the synchronism of this alternating current with the alternating current of the three-phase A-C power source, so that smooth switching free from shocks becomes possible.

Abstract: An electrical motor contactor or controller is taught in which control signals from remotely located pushbuttons are supplied to the logic portion of the controller for the purpose of initiating or stopping a predetermined contactor or controller actions. The controller or contactor is of a universal nature adapted for the acceptance of relatively high voltage AC control signals or relatively low voltage DC control levels. For instance, a 120-volt AC signal may be provided or a 5-volt DC level may be provided. Because an AC signal may be provided to the controller, capacitive filter elements are utilized in the control circuit for filtering transients or AC components above a predetermined frequency which may be 60 Hz for example. Furthermore, voltage regulator elements within the control circuit and the microprocessor input terminals within the control circuit represent relatively high impedance in the discharge path for the aforementioned capacitors.

Abstract: In a load commutated inverter (LCI) motor drive, the motor is started from a rotor rest position by modulating the rotor winding with a field current at a constant rate to induce stator voltages which are detected in terms of signs, so as to identify the rotor rest position. The induced stator voltages are used to select an initial pair of thyristors of the inverter to be turned on in the firing sequence for the chosen direction of rotation under normal operation of the drive.

Abstract: An apparatus for starting and running a plurality of three-phase motors from a single-phase power source is described. Two of the main coils of a three-phase motor are used to run the motor as a single-phase induction motor. The third coil of a three-phase motor is used as a starting coil and is selectively powered through a switch and a capacitor. The capacitor provides the necessary difference in the phase angle of the current in the starting coil and the main coils to provide starting torque for the operation of the motor.

Abstract: In a single phase AC induction motor having a main winding (1) and an auxiliary winding (2) both connectable to an AC power source (4), and having a start switch (6, 74) for automatically connecting and disconnecting the auxiliary winding (2) to and from the AC source (4) in starting and running modes, respectively, and having a user operated reversing switch (207-212) for reversing the voltage polarity applied from the AC source (4) to one of the windings relative to the other winding, low cost circuitry is provided for detecting the polarity reversal by sensing when one of the main and auxiliary winding voltages shifts from a leading to a lagging position relative to the other winding voltage, whereupon the circuit automatically instantly reconnects the auxiliary winding (2) to the AC source (4) to immediately apply reverse torque.

Abstract: An electric drive system uses a multiphase alternating current motor and inverter to convert power from a battery source to provide propulsion. The phase sets defined by the motor stator winding are excited by a corresponding plurality of inverters. Time harmonic currents in the windings are effectively suppressed by providing the drive motor in a configuration having high leakage inductance in the stator winding. The windings are arranged in sets of multiples of three-phase windings. In the illustrated embodiment, the inverters are arranged to define three-phase inverters for exciting m sets, where m.gtoreq.2, of three-phase windings of the motor stator. The number of multiphase winding sets is determined in a manner that eliminates the need for paralleling of inverter switching devices.

Abstract: In a pumping-up generator/motor system comprising an induction generator/motor, at least one cyclo-converter connected to the secondary winding of the induction generator motor for controlling the rotational speed of the generator/motor in the motor mode and for maintaining the output frequency thereof in the generator mode at a constant level, the center of the speed range of the generator/motor in the generator mode is set near the synchronous speed thereof and a plurality of converter units constituting each cyclo-converter are connected in parallel in the generator mode, and in series in the motor mode thereby allowing the capacity of the cyclo-converter to be made smaller.

Abstract: In the prior art, a DC motor is often utilized for controlling speed of servomechanism for its simpleness in operation and excellent control. However, as a DC motor is equipped with brushes and commutators, it inconveniently requires periodical maintenance and inspections in order to keep normal operation. As electric semiconductors such as power transistors along with control technology have made a remarkable progress in recent years, a demand for motors which do not need maintenance is keenly felt. Studies have been conducted on control by DC motors and some have been put into practice. According to this invention, there is provided a synchronous motor which has a small field loss and which does not need slip rings or rotary transformers. Further, there is provided synchronous motor which can be simply constructed at a low cost without using a permanent magnet as a rotor and which can realize a larger capacity, and provided a control unit for the synchronous motor.

Abstract: Disclosed in a variable speed pumping-up electrical power system comprising a variable speed generator/motor, a frequency converter connected between the generator/motor and an a.c. power system, a controller controlling an effective power input to the generator/motor by controlling the frequency converter on the basis of the difference between an actual effective power input from the a.c. power system and an externally-applied effective power command, and a correction circuit correcting the effective power command on the basis of the difference between the frequency of the a.c. power system and a frequency setting.

Abstract: A reluctance motor control system is stabilized by a load angle feedback control loop provided by a computation of the load angle from sensed voltage and current on the terminals of the motor with the assist of a derived frequency signal. The motor is operated at most efficient load angle in motoring or braking, while the motor voltage is being controlled so as to maintain the desired load angle as the speed and/or load vary.

Abstract: An autosynchronous motor comprises a control and power circuit for the windings of a stator generating a rotating field the angular direction of which is a function of the magnetizing direction of the permanent magnet of the rotor, and to a positioning device producing a signal representing the angular position of the rotor relative to the stator windings. This positioning device emits one pulse per rotation; it comprises a moveable member integral with the rotor and a steady or fixed member integral with the stator.The stator member of the positioning device and the stator comprise complementary means so that this stator member can, by manual operation, be rotated around the axis of the motor. Marking references are provided for predetermined angular positions of the stator member. These complementary means are, for example, on the stator constituted by a ball repelled by a spring and on the stator member by a number of notches equal to the number of pairs of the rotor.

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 connected to a source of AC power via a selector switch for multi-speed operation of the motor.

Abstract: An electric motor run and brake control circuit for controlling alternating current to a three-phase motor in which the circuit is operated by a single logic level input signal. When the input signal is low, a run relay is closed and AC power is applied to the motor. When the input signal goes high, the run relay is opened and the motor is braked for a fast stop. A brake capacitor and charge resistor limit both the time during which braking current is applied and the repetition rate of braking cycles.

Abstract: When an inverter is disconnected from a rotating motor due to power failure or motor accident, it is necessary to connect the inverter power again to the rotating motor by the inertia force in order to keep the motor rotating. To achieve the above reconnection, the inverter is controlled in accordance with open-loop control method, without use of any motor speed detecting means, thus improving control response speed. In reconnection, the inverter is started at a frequency higher than the rotating motor speed and at a voltage lower than the rated value; when a predetermined time has elapsed after the starting voltage was applied to the motor, only the frequency is decreased; when inverter driving current drops below a predetermined value, the frequency is held and only the voltage is increased until the voltage-to-frequency ratio reaches a predetermined value.

Abstract: A speed control apparatus for a synchronous motor is provided with a resolver fixedly connected to a rotor of the motor, which produces a phase modulated signal corresponding to an angular position of revolving magnetic field in the motor, a circuit for converting the phase modulated signal into a rotational speed signal of the motor, a phase compensation circuit for advancing in phase a reference signal in accordance with the rotational speed signal, a multiplier for multiplying the phase modulated signal and a rotational speed instruction signal, a synchronous rectifier for synchronously rectifying the output of the multiplier by an output of the phase compensation circuit, and a current control loop circuit for receiving an output of the synchronous rectifier and for producing a signal having a phase angle delayed as much as the phase angle is advanced in the phase compensation circuit.

Abstract: A method and apparatus for damping oscillations in the rotor load angle of a synchronous motor to provide stable rotational alignment in high precision applications. The damping method includes sensing the angular position of the rotor and utilizing the position signal to generate an error signal in response to changes in the period of rotation of the rotor. The error signal is coupled to phase shift amplifiers which shift the phase of the motor drive signal in a direction to damp out the oscillations in the rotor load angle.

Abstract: In an induction motor drive controlled by SCR devices connected in the AC power supply phase lines of the motor, a plurality of channels establish, on a common input to a digital gate pulse generator of the SCR's, various signals occurring in the course of the motor drive operation. These signals relate to motor operating modes, such as soft start tripping, current limit. A central large scale integrated (LSI) chip responds digitally to such common input so as to establish the required firing angle at any instant and for any situation.

Abstract: A reduced voltage starter for gradually starting a polyphase motor having an acceleration control circuit for gradually applying power to the motor and detector circuits for detecting various fault conditions for terminating power to the motor. A shorted solid state switch detector senses when one of the semiconductor switches applying power to the motor is shorted to terminate the application of power from the remaining phases. A phase angle control circuit insures a uniform application of power to the motor. A phase rotation detection circuit detects when the three phases are in other than their correct sequence and terminates power in the event of such detection. An underload detection circuit senses when the current drops beneath a preselected reference after the motor has reached its full speed and terminates power in response to such detection. A line-to-line to line-to-neutral converter produces signals representative of the line-to-neutral voltages which are necessary for other circuit functions.