Abstract: The invention provides an electrically movable vehicle drivable by a simplified mode of control and a control program for driving the vehicle. A normalized value Y? representing translation motion and a normalized value X? representing turning motion are fed from a command value input unit 110 to a velocity command value calculating unit 120. The calculating unit 120 determines a translation velocity command value Vg—trg based on the normalized value Y?. The calculating unit 120 determines a turn angular velocity command value ?f—trg that will always satisfy Expression (2–4) for preventing the vehicle from falling down. The translation velocity command value Vg—trg and the turn angular velocity command value ?f—trg determined by the unit 120 are fed to a control command value calculating unit 130, which calculates control command values for left and right drive wheels. The control command values are fed to a motor control unit 140 to control motors Mr, Ml and control the drive wheels.

Abstract: An outer-rotor variable-speed motor, to which single-phase AC power is applied and on which a rotor is provided outside a stator, comprises first and second main windings provided on a stator of the motor to form a plurality of poles, a frequency detector for detecting the frequency of AC power applied to the motor, and a relay for connecting the first and second main windings in series if the detected frequency is 60 Hz and connecting the first and second main windings in parallel if the detected frequency is 50 Hz. The speed of the motor is kept constant even when power at different frequencies is applied, so that it is possible to reduce the manufacturing cost of the motor and reduce the power consumption, and also to reduce electromagnetic noise from the motor.

Abstract: A compressor driver for a compressor is provided, wherein at the start of the compressor, a phase of the current flowing in the motor is controlled to be ahead of an induction voltage, then the advancement of the phase is controlled to decrease. Under an unstable condition to detect a position, such as at the start under pressure-difference, the foregoing control allows the phase to advance up to the current-phase where the max. torque can be produced, thereby drawing the instantaneous max. torque of the motor for starting the compressor. Then the control reduces the advancement for obtaining a stable operation.

Abstract: A voltage detection section and current detection section detect a voltage and current supplied to a motor, and the detected voltage and current are supplied to a position detection section. An angular speed output from the position detection section is supplied to a differentiator to output an angular acceleration. A fundamental wave component extraction section extracts a fundamental wave component of the angular acceleration, and the extracted fundamental wave component is supplied to an amplitude adjustment section. The output of the amplitude adjustment section is subtracted from the average current command by a subtraction section. This subtraction result, current detection value, and the rotor position from the position detection section are supplied to a current control section to carry out the current control operation so as to obtain a current command.

Abstract: The invention concerns a drive arrangement of a lifting gear and/or a traveling gear, with a pole-reversible rotary-current motor with windings for at least two different actuating speeds, with a pole switching element connecting the rotary-current motor to a voltage supply for changing between the actuating speeds of the rotary-current motor. In order to create a drive arrangement of a lifting gear and/or a traveling gear with a rotary-current motor, whose switching behavior is optimized in relation to the actuation of the rotary-current motor, it is proposed that a power switching element (3) be hooked up in front of the pole switching element (5), and it can be separated from the voltage supply via the power switching element (3) for the pole switching process of the rotary-current motor (2).

Abstract: An apparatus, method and system of wash action control for an automatic washing machine. A manually operable user interface allows selection from between a plurality of discrete agitation speed selections which comprise at least a continuous speed agitation mode for a given agitation period during a wash cycle and an intermittent speed agitation mode for at least a part of a given agitation period. The intermittent speed agitation mode automatically varies agitation speed between at least two sub-periods of the given agitation period. The variation in agitation speed can be between a faster and a slower speed or a certain speed and no agitation.

Abstract: A system and method for controlling an electric motor is disclosed. The method comprises determining the operating load of the electric motor and then calculating the voltage to be applied to the electric motor in response to the operating load. The voltage to be applied operates the motor in an efficient manner for the given load. The frequency of the voltage to be applied to the electric motor is calculated in response to the operating load such that the frequency of the voltage to be applied operates the motor in an efficient manner. Power is applied to the motor with the voltage and frequency calculated in order to operate the motor in an efficient manner for the given load.

Abstract: Apparatus for driving a three-phase compressor assembly from a single-phase electrical power supply having first and second power lines, said three-phase compressor assembly comprising a compressor having a rotatable shaft, an electrical motor having a rotatable shaft coupled to the rotatable shaft of the compressor, the electrical motor having at least first, second and third motor windings and having at least first, second and third terminals connected to the first, second and third windings, means adapted to connect the first and second power lines of the single-phase power supply to the first and second terminals and a torque augmentation circuit for injecting current into the third terminal and including a capacitor and an electrical component in series with the capacitor, said electrical component having resistive characteristics and having means for essentially interrupting the current being injected into the third terminal.

Abstract: A method for changing the speed of a motor group, in particular for starting or stopping it, the motor group comprising a plurality of squirrel-cage induction motors or synchronous motors and network converters arranged for their control, when the nominal supply power (Pns), the acceleration power (Pacct) at the final speed (Vmax) of the motors and the losses (Ploss) of the used power are known.

Abstract: A switch for a variable-speed induction motor includes conductive connecting pieces, a rotary member, and a driving unit. The connecting pieces are mounted in a housing, are adapted to be connected to the induction motor, and have distal contact parts that surround an axis of the housing. The distal contact parts of any two of the connecting pieces form either an angular or height difference therebetween with respect to the axis. The rotary member is rotatable about the axis inside the housing, and is formed with contacting regions that are arranged along the axis and that are in sliding contact with the distal contact parts. The driving unit is operable so as to drive rotation of the rotary member about the axis such that the connecting pieces are bridged selectively and electrically by the contacting regions of the rotary member for varying the speed of the induction motor.

Abstract: A Hall sensing circuit generates a positional detection signal representative of a positional relationship between a rotor and a phase coil of a motor. A signal synthesizing circuit transforms the positional detection signal to a driving signal. Based on a comparison of the driving signal and a high-frequency reference signal, a pulse signal is generated for controlling a switching circuit to dive the motor. A current error signal is supplied through feedback to adjust a relative relationship between an amplitude of the drive signal and an amplitude of the high-frequency reference signal, thereby changing a duty ratio of the pulse signal. A duty-ratio limiting circuit is provided to limit the duty ratio of the pulse signal for ensuring a reliable rotation of the motor.

Abstract: The invention concerns a method for regulating the rotation speed, of a motor with which a digital rotation speed controller is associated and which, during operation, furnishes an actual-value signal for the rotation speed in the form of a rotation speed frequency signal, toward a target rotation speed setpoint defined in the form of a setpoint frequency signal, having the following steps: in a first time segment, a first numerical frequency value that characterizes the rotation speed of the motor is ascertained from the rotation speed frequency signal; in a second time segment that is substantially simultaneous with the first time segment, a second numerical frequency value that characterizes the frequency of the setpoint frequency signal is ascertained from the setpoint frequency signal; by means of the first and second numerical frequency values, the rotation speed of the motor is regulated in the digital rotation speed controller to a rotation speed that is associated with the setpoint frequency signal a

Abstract: A single phase, three-speed induction motor having 4, 6, and 8-pole speed configurations. In one embodiment, the motor is constructed and arranged to be used in connection with a washing machine. The 8-pole speed winding shares a portion of the 4-pole speed winding, but not all of the 4-pole speed winding is used in the 8-pole configuration. In one embodiment, the 4-pole speed winding includes four winding portions and the 8-pole speed configuration uses two of the four winding portions without the need for additional switch contacts to reconfigure the motor for operating in the 4-pole mode or the 6-pole mode. In one embodiment, shared winding portions are wound on the stator core in a generally non-sinusoidal distribution and non-shared winding portions are wound on the stator core in a generally sinusoidal distribution.

Abstract: A simple and economical mechanism providing automatic motor control. The mechanism includes a motor-rated relay directly connected to line voltage and the input terminal of a motor winding, and receiving a signal from a sensing device connected to line voltage and to a signal input on the relay. The relay and sensing device may be housed within a waterproof enclosure, or may be separately housed within a connection enclosure and a separate sensing device enclosure remote from the connection enclosure, the two enclosures being connected by a cable. The sensing device triggers the relay to control the supply of current to the motor winding.

Abstract: A stator in a synchronous fan includes first and second main windings, and an auxiliary winding. Illustratively, the first and second main windings are wound in a bifilar arrangement. In addition, the stator has a switch to switch the stator between a plurality of configurations. One of those configurations is an induction configuration that permits the first main winding to induce a voltage in the auxiliary winding when a current (e.g., a time-varying current) is transmitted through the first main winding. Moreover, the first main winding is electrically isolated from the auxiliary winding when in the induction configuration.

Abstract: A washing machine motor drive device drives a motor using an inverter circuit, which implements a constant torque control through a change in the torque-revolution speed characteristic of the motor. This facilitates an easy control of braking torque (negative torque), thereby providing a maximized braking torque. An easy control of regenerative energy is also provided, and back electromotive force is consumed by the internal resistance of the motor. Practically described, DC power of a rectifier circuit connected to an alternating current source is converted by an inverter circuit into AC power for driving the motor for operating an agitator or a washing/spinning tub. Motor rotor position is detected by rotor position detector, motor current is detected by current detector, and a control device controls the inverter circuit for resolving the motor current into a current component corresponding to magnetic flux and a current component corresponding to torque.

Abstract: A speed controller for a single phase motor such as a permanent split capacitor motor allows the motor to be operated at a first speed, n1, and a lower speed, n2. High speed motor operation is produced by passing a single phase AC current through both the main and auxiliary windings of the motor. For low speed operation, the controller passes first and second reduced frequency AC waveforms through the motor's auxiliary and main windings, respectively. The first waveform bypasses the motor's auxiliary winding capacitor and is phase shifted 90 degrees from the second AC waveform. A split source capable of generating an AC signal and its inverted signal can be used by the controller to generate the reduced frequency waveforms. Specifically, the controller uses selected half cycles from each split source signal to produce the reduced frequency waveforms.

Abstract: A sensorless motor starting system of a simplified structure is capable of starting a sensorless spindle motor under optimal target starting conditions with low power consumption in accordance with the motor type and the kind of an optical disc to be driven, by executing manual fine adjustment of start parameters in response to any abnormal rotation caused at the start time. In this system, a rotation frequency signal is outputted from an edge detector on the basis of position signals in a start acceleration mode, and then is compared with a reference frequency signal by a comparator. And if the result of the decision therefrom signifies abnormal rotation, a switch is turned to its another terminal to select a manual setting mode. An operator performs manual fine adjustments of a phase switching time, a phase switching number and a drive voltage in order while monitoring phase switching control signals and position signals to thereby normalize the start state of the sensorless spindle motor.

Abstract: A motor controller controls a motor operated by an AC line voltage. The controller includes an SCR connectable between an AC line and a motor terminal for controlling application of AC line voltage to the motor. Contacts are connected in parallel with the SCRs for selectively bypassing the SCRs. A sensing circuit senses if the contacts are bypassing the SCRs. A control is connected to the sensing circuit and the SCRs for varying relative duration of on time and off time of the SCRs during each cycle of line voltage to control motor voltage at a reference level. The control adds a time delay to a running operation prior to turning the SCRs off to stop the motor if the contacts are bypassing the SCRs.

Abstract: A method for changing the speed of a motor group, in particular for starting or stopping it, the motor group comprising a plurality of squirrel-cage induction motors or synchronous motors and network converters arranged for their control, when the nominal supply power (Pns), the acceleration power (Pacct) at the final speed (Vmax) of the motors and the losses (Ploss) of the used power are known.

Abstract: A washing machine motor drive device for driving a motor using an inverter circuit, which implements a constant torque control through a change in the torque-revolution speed characteristic of a motor. It facilitates an easy control of braking torque (negative torque), thereby providing a maximized braking torque. An easy control of regenerative energy is also provided, and the back electromotive force is consumed by the internal resistance of motor. Practically described; DC power of rectifier circuit connected to an alternating current source is converted by an inverter circuit into AC power for driving a motor for operating an agitator or a washing/spinning tub, motor rotor position is detected by rotor position detector, motor current is detected by current detector, control device controls the inverter circuit for resolving motor current into a current component corresponding to magnetic flux and a current component corresponding to torque.

Abstract: A method and apparatus for controlling a permanent magnet synchronous motor (8) coupled to a turbo engine such that transient current and steady state current are minimized. The method comprises the steps of, for a given DC bus voltage, determining an acceleration profile as a function of a voltage-offset value, a low-speed rated speed value, a high-speed rated speed value, a first desired speed for warming up the turbo engine, and a second desired speed where the turbo engine has sufficient torque to accelerate to its rated speed without the aid of the permanent magnet synchronous motor (8).

Abstract: A method and apparatus for controlling a permanent magnet synchronous motor (8) coupled to a turbo engine such that transient current and steady state current are minimized. The method comprises the steps of, for a given DC bus voltage, determining an acceleration profile as a function of a voltage-offset value, a low-speed rated speed value, a high-speed rated speed value, a first desired speed for warming up the turbo engine, and a second desired speed where the turbo engine has sufficient torque to accelerate to its rated speed without the aid of the permanent magnet synchronous motor (8).

Abstract: A fan motor with constant speed control comprises a microprocessor system, a bus control logic, a register for actual fan speed, a register for fan state, a register for speed set-up, a linear variable voltage circuit control logic, and a braking/running enabling control logic. The microprocessor system is connected via the bus control logic to the register for actual fan speed, the register for fan state, and the register for speed set-up. The register for fan state sets up enabling of braking and running by means of controlling output voltage by the braking/running enabling control logic. The register for speed set-up sets up speed values by the microprocessor system. After comparing a speed value to an actual fan speed signal by the linear variable voltage circuit control logic, the linear variable voltage circuit control logic generates a linear variable voltage (drive voltage) which is outputted to the fan via the braking/running enabling control logic.

Abstract: A method is provided for controlling a three-phase, AC induction motor. Each phase of the AC induction motor is connected to an AC input source by a thyristor switch and a bypass contactor connected in parallel in order to provide voltage and current to the AC induction motor. The method includes the steps of sequentially firing pairs of thyristor switches at a predetermined initial gamma firing angle. A new gamma firing angle is calculated which is dependant upon the initial gamma firing angle. Thereafter, pairs of thyristor switches are fired at the new gamma firing angle. The new gamma firing angle is provided as the initial gamma firing angle and a new gamma firing angle is calculated. The process is repeated until the AC induction motor reaches its full operating speed.

Abstract: A method is provided for controlling the starting of an AC induction motor with a soft starter. The windings are connected in a delta configuration and each winding has a corresponding thyristor switch connected in series therewith such that each winding and thyristor switch combination is connected between two corresponding terminals of the AC induction motor. Alpha control of the thyristor switches is utilized to start the AC induction motor and bring the AC induction motor to near full operating speed. As the AC induction motor nears full operating speed, gamma control of the thyristor switches is utilized to bring the AC induction motor to full operating speed. With the AC induction motor at full operating speed, bypass contactors, in parallel across corresponding thyristor switches, are closed and the AC induction motor operates in a conventional manner.

Abstract: A supplemental circuit board is provided for a furnace and air conditioning system to power the blower motor so that there is normal heat speed during a heat cycle, and normal, full speed when there is a normal cooling cycle. When there is a call for economy, dehumidification, or partial speed cooling, an inverter provides pulsating power for efficient reduced blower speed operation. An actuator circuit provides a blower-motor in-use signal, and a low-speed logic circuit provides a low-speed signal when there is a call for reduced speed cooling. In case of circuit failure, the arrangement defaults to normal speed operation.

Abstract: An induction motor system operable in a wet environment comprises an induction motor and an apparatus for controlling the speed of the motor. The motor is adapted to be coupled to an AC source for supplying an AC signal. The motor includes a rotor having rotor laminations. The reflected rotor resistance over reflected rotor reactance ratio of the motor is adjusted to be greater than one. The controlling apparatus includes a switching device, user controls, controller means and isolation means. The switching device is connected in series with the motor and is operative in either a high impedance state wherein significant current flow through the motor is prevented or a low impedance state wherein current flow through the motor is substantially undisturbed. The user controls provide motor speed input signals.

Abstract: A method and apparatus for controlling a permanent magnet synchronous motor (8) coupled to a turbo engine such that transient current and steady state current are minimized. The method comprises the steps of, for a given DC bus voltage, determining an acceleration profile as a function of a voltage-offset value, a low-speed rated speed value, a high-speed rated speed value, a first desired speed for warming up the turbo engine, and a second desired speed where the turbo engine has sufficient torque to accelerate to its rated speed without the aid of the permanent magnet synchronous motor (8).

Abstract: An objective of this invention is to provide a drive control device to control the drive applied to a high-speed rotor unit which would have no circuits in either its pump unit A or its power supply unit B that would limit the use of the device with various types of rotor units, which could easily be used with various types of rotor units, and whose power supply unit B could be used generally. The drive control device for controlling a high-speed rotor unit according to this invention has a power supply unit contains a set of tables of constants needed to control the various types of rotor units with which the drive control device might be used. These constants allow the rotation of the high-speed rotor unit to be adjusted or set according to the type of rotor unit. A signal intended to detect and indicate the type of rotor unit to be driven by the rotor is automatically detected and input before the motor is driven. Based on this signal, the appropriate table is selected.

Abstract: A permanent split capacitor motor operable in a full mode and in a modulated mode for improving efficiency. The motor includes a stator and a rotor in rotational relationship with the stator. The motor also includes a single set of windings wound on the stator. The windings are in a magnetically coupled relationship with each other such that one of the windings is a main motor winding while the other is an auxiliary motor winding. The windings define a plurality of A-ratios as a function of turns in the main motor winding compared to turns in the auxiliary motor winding. A switching circuit selectively energizes the first and second windings in a full mode configuration and in a modulated mode configuration based on motor load conditions. In the full mode configuration, the A-ratio of the windings is greater than in the modulated mode configuration.

Abstract: The invention relates to a drive device for a rotary anode of an X-ray tube, including an induction motor (13) whereto an alternating voltage can be applied by means of an inverter (20), and also including a control unit (22) for controlling the inverter (20), the switching frequency of the inverter (20) being variable in time, in conformity with a frequency time characteristic, by means of the control unit (22). It is the object of the invention to provide a drive device for a rotary anode of an X-ray tube as well as a suitable control method which ensures the temperature-independent starting up of the rotary anode.

Abstract: A machine tool has a spindle with a tooling body mounted thereon, a detector for detecting an acceleration time for the tooling body to reach from a rotation start to a predetermined rpm, a controller for controlling an rpm of the spindle under a lowered limit when the acceleration time is longer than a reference time. Another detector detects an asymmetricity of radial forces acting on the spindle, and the controller controls the rpm of the spindle under a lowered limit when the asymmetricity of radial forces exceeds a reference degree.

Abstract: A wash action control system is used to control the agitation speed of a washing machine. The invention includes a wash speed selection switch which controls the agitation speed of the agitator. The wash speed selection switch has an infinite number of possible wash speed settings and includes various secondary switches for affecting various aspects of the wash speed control.

Abstract: A novel two-phase brushless motor drive assembly. The motor drive assembly is made of two parts, a motor assemble and a motor control circuit.The motor assembly, receives a first wire providing electric power, a second wire providing a ground connection, and a third wire. The motor assembly includes, a two-phase brushless motor. It also includes a motor drive circuit, responsive to a speed control voltage signal on the third wire and the electric power on the first wire, providing drive power to the motor to drive the motor to a speed determined by the speed control voltage signal. The motor assembly also includes a sensor circuit providing a sensed speed current signal on the third wire, having a current representing the rotational speed of the motor.

Abstract: An apparatus for controlling a stepping motor used for moving a carriage having a pickup from a first position to a second position, the apparatus having: a calculating device for calculating a moving distance between the first position and the second position; a setting device for setting an acceleration area to accelerate the stepping motor and a deceleration area to decelerate the stepping motor, on the basis of the moving distance; and a driving device for driving the stepping motor by a one-two-phase excitation method until rotation velocity of the stepping motor increases to a predetermined velocity in the acceleration area, driving the stepping motor by a two-phase excitation method after rotation velocity of the stepping motor increases to the predetermined velocity in the acceleration area, driving the stepping motor by the two-phase excitation method until rotation velocity of the stepping motor decreases to the predetermined velocity in the deceleration area, and driving the stepping motor by the o

Abstract: A control circuit for an electric motor having start, low speed and high speed windings reactivates the start winding at different reduced motor speeds depending upon whether the motor is running on the low speed winding or the high speed winding. Reactivation of the start winding while the motor is running on the low speed winding automatically deactivates the low speed winding and activates the high speed winding.

Abstract: A safety control arrangement for escalators includes a detector for generating a trigger signal, and a microprocessor connected to a memory. A serial data communications bus connects the detector to the processor. The memory includes toggling and interrogating routines which permit verifying proper operability of the detector.

Abstract: A speed control apparatus for determining and controlling the speed of rotation of a rotor in an AC motor. The motor includes a stator having main and auxiliary windings. Main and auxiliary winding controllers control the operational input signals supplied to the main and auxiliary windings by a signal generator. A pulse generator is connected to the main winding for providing a test pulse during a speed measurement operation. The test pulse magnetizes a portion of the rotor which induces a feedback EMF signal in the auxiliary winding. A feedback sensor circuit receives the feedback signal and forwards it to a microprocessor. The microprocessor calculates the rotational speed of the rotor based on the feedback signal.

Abstract: A multi-speed switching device particularly suitable for providing multi-speed starts for a motor, especially a two-speed motor, is provided with a high-reliability solid state switch for controlling a phased start winding of the motor, and an inexpensive switch for accommodating a lesser number of starts at an auxiliary speed. The high-reliability switch is a triac switched off during every motor start as the motor comes up to an operating speed. The inexpensive switch is an electromechanical relay that switches between a main run winding and an auxiliary speed run winding, and which is energized by voltage appearing across the solid state switch when it is switched off.

Abstract: A variable speed controller for an induction motor that estimates the primary angular frequency and the speed without causing any error in the drive region where the induced voltage is low. The primary angular frequency and speed estimating device includes: a changeover signal generator that generates a changeover signal indicative of a first mode of operation when the induced voltage is greater than the changeover threshold, and a second mode of operation when the induced voltage is less than the changeover threshold; a differentiator, filter, etc.

Abstract: An apparatus and method for generating digital electrical signals which are representative of the angular position and rotational velocity of a rotatable shaft component in a servomechanism includes a resolver which is connected to the rotatable component. The resolver generates analog electrical output signals which are representative of an excitation signal modulated by both the sine and cosine of the electrical angular or position of the motor. The output signals from the resolver are fed to a digital signal processing circuit which employs software algorithm techniques to define a plurality of tasks which are implemented sequentially to obtain the desired angular position and velocity signals. First, the sine and cosine signals are read from the resolver through respective analog-to-digital converters. The sine and cosine signals are demodulated by multiplication with the excitation signal, and the undesired higher frequency components are deleted by filtering.

Abstract: An apparatus for controlling the speed of an induction motor includes a first winding and a second winding. The first winding and second winding are adapted to be coupled to an AC source for supplying an AC input signal. A first switching device is coupled to the first winding and a second switching device is coupled to the second winding. Each of the switching devices is operative in a low impedance state enabling current to flow through the associated winding of each switching device and a high impedance state preventing significant current flow through the associated winding of each switching device. A controller switches each of the switching devices from the high impedance state to the low impedance state in a sequence for controlling the current in the windings, which induces a phase shift between the AC voltages across the windings.

Abstract: A control circuit for a two speed electric motor includes high and low speed electronic switches. The high speed electronic switch is biased off when the low speed electronic switch is biased on. The low speed run winding of the motor is activatable only through the low speed electronic switch. The high speed run winding of the motor is activatable either directly through a high speed setting of a speed selector switch or through the high speed electronic switch in a low speed setting of the speed selector switch. Upon activation of the motor start winding, the low speed electronic switch is off and the high speed electronic switch is on.

Abstract: A start-up controller is programmed to continuously monitor the start-up acceleration of a motor using a stored acceleration profile to check the acceleration time against specification limits for the particular motor in which the controller is incorporated. The acceleration profile is an ordinal series of acceleration profile points in which each point is associated with a profile motor speed and a profile elapsed time. The controller terminates the acceleration of the motor if overall time elapsed since the start of acceleration is greater than the profile elapsed time associated with a profile point that is designated by the motor speed.

Abstract: An apparatus and method for generating digital electrical signals which are representative of the angular position and rotational velocity of a rotatable shaft in a servomechanism includes a resolver which is connected to the rotatable component. The resolver generates analog electrical output signals which are representative of an excitation signal modulated by both the sine and cosine of the electrical angular position of the motor. The output signals from the resolver are fed to a digital signal processing circuit which employs software algorithm techniques to define a plurality of tasks which are implemented sequentially to obtain the desired angular position and velocity signals. First, the sine and cosine signals are read from the resolver through respective analog-to-digital converters. The sine and cosine signals are demodulated by multiplication with the excitation signal, and the undesired higher frequency components are deleted by filtering.

Abstract: An apparatus for controlling the supply of power to a variable-speed induction motor converts an AC power source voltage to a motor supply voltage at a designated frequency, with the amplitude of the motor supply voltage being controlled in accordance with the motor load such that the degree of slip conforms to a predetermined optimum slip charactistic, whereby high efficiency and stability are maintained over a wide range of load values. The motor supply voltage amplitude is detected to provide an indication of the motor load, an optimum value of an operating parameter of the motor which varies in accordance with degree of slip is derived based on the designated frequency and the detected voltage amplitude, using a predetermined function corresponding to that frequency, and the motor supply voltage amplitude is controlled such as to reduce an amount of difference between the optimum value of the operating parameter and a detected value of that parameter.

Abstract: A control apparatus for controlling a motor includes: a command unit for generating a command signal including a running command signal and a stopping command signal; a rotation sensor for generating an AC signal having a period corresponding to a rotational speed of the motor; a speed detector for detecting a rotational speed of the motor from the AC signal generated by the rotation sensor; a compensator for generating a control signal for controlling the motor, and a driver for driving the motor in response to the control signal generated by the compensator.

Abstract: A zoning circulator for circulating fluid within a zone in a hydronic heating or cooling system includes a zoning circulator controller including a speed regulating circuit for controlling the speed of a circulator motor. The circulator controller also includes an override circuit for operating the circulator at a high speed, high starting torque for several seconds to overcome frictional resistances between the moving parts of the motor and then tapers down to the speed established by the speed regulating circuit.

Abstract: A method for starting an unexcited, multiple phase, alternating current induction motor rotating at an unknown speed is provided. The method includes generating an output signal with an AC drive at a predetermined frequency in order to energize the motor. The output signal has independently adjustable frequency and voltage components. A speed reference is provided which is functionally related to the frequency of the output signal. The voltage of the output signal is ramped at a predetermined rate and the frequency of the output signal is adjusted such that the voltage of the output signal equals the motor's set point and the speed reference is substantially equal to the speed of the motor. The motor then enters the normal operating mode.