Abstract: A method for providing electrical energy to an actuator is disclosed. In at least one embodiment, the method includes having a first voltage (UBUS) from a data bus; ii) converting the electric current to a current having a second voltage that is higher than the first voltage; iii) storing electrical energy of the second electric current; and discharging the stored electrical energy to an actuator. A device is also disclosed for providing electrical energy to an actuator.

Abstract: A method and apparatuses are implemented for electric power systems. An apparatus for power conversion according to one embodiment comprises: a multiple function power converter (77), the multiple function power converter (77) being capable of performing functions of a static inverter, and being capable of at least one of performing functions of a motor controller, and performing functions of a start converter to use a generator as a starter. An architecture system for aircraft according to another embodiment comprises: one or more rectifiers (408), wherein the one or more rectifiers (408) receive at least one high frequency AC power input; and a plurality of power conversion devices (78) optionally connectable to drive at least one high frequency generator (105) as a starter and at least one load, the input of each power conversion device (78) being connected to at least one rectifier (408).

Abstract: A motor system is configured by: detecting a duration of idle stop by an idle stop end state detection unit 101 when the idle stop mode of the fuel cell ends; estimating recovery time taken for total voltage of the fuel cell to reach voltage at the idle operation by a fuel cell stack total voltage recovery time estimation unit based on the detected duration; and correcting and reducing a changing rate of the drive motor request torque by the drive motor request torque reduction correction unit 103 based on the estimated recovery time.

Abstract: Method and apparatus for accelerating a multi-phase motor having a rotatable rotor are disclosed. A first commutation state in which the rotor resides is identified, after which a Proportional, Integral and Derivative (PID) control routine is executed for closed loop control of an acceleration of the rotor from a stopped position to an intermediate velocity, after which back electromotive force (Bemf) commutation is used to control the motor. The PID control routine utilizes a loop gain value optimized through voltage feedback indicative of a response of windings of the rotor to an application of a drive current across the windings. Based on the voltage feedback a controller programmed with the PID control routine provides an updated commanded current for each successive commutation state of the motor for use by a motor driver circuitry, which drives the motor through each commutation state until attainment of the intermediate velocity.

Abstract: A method of using an externally powered HVAC system for an over-the-road motor coach includes coupling the HVAC system to an external shore power source at a temporary stop location for the over-the-road motor coach while the over-the-road motor coach is parked and vehicle engine is turned off; receiving electrical power from the electrical outlet to power the HVAC system; and using the HVAC system to circulate refrigerant for heating or cooling an interior cabin of the over-the-road motor coach and power HVAC fans to ventilate the interior cabin of the over-the-road motor coach.

Abstract: Methods and systems are provided for operating an electric motor having at least one winding coupled to first and second power supplies. A torque command for the electric motor is received. A present power reserve for the first and second power supplies is determined based at least in part on the torque command. An operating voltage for the second power supply is determined based on the present power reserve. The operating voltage for the second power supply is applied to the at least one winding. The application of the operating voltage allowing the present power reserve to flow between the first and second power supplies and the motor.

Abstract: A method of using an externally powered HVAC system for an over-the-road motor coach includes coupling the HVAC system to an external shore power source at a temporary stop location for the over-the-road motor coach while the over-the-road motor coach is parked and vehicle engine is turned off; receiving electrical power from the electrical outlet to power the HVAC system; and using the HVAC system to circulate refrigerant for heating or cooling an interior cabin of the over-the-road motor coach and power HVAC fans to ventilate the interior cabin of the over-the-road motor coach.

Abstract: A motor driving apparatus having a converter, which receives AC voltage and converts it to DC power, and an inverter, which receives the DC power and converts it to AC power, includes a charge/discharge control circuit and a capacitor connected in parallel to a link section between the converter and the inverter, and energy stored in the capacitor C8 is charged and discharged at arbitrary timing by the charge/discharge control circuit. The invention thus provides a motor driving apparatus that supplies energy to a motor so that the peak of the input current from a power supply to the motor can also be suppressed when particularly large energy is needed during the second half period of motor acceleration.

Abstract: A power supply device for vehicles, output units (10a, 10b) thereof are connected to a motor (5), includes a fuel cell (1) which is connected to the output units (10a, 10b), a capacitor (2) which is connected in parallel to the fuel cell (1), a lithium ion battery (21) which is connected in parallel to the capacitor (2) through a DC/DC converter (20), and a current control means (32) which limits an output current of the lithium ion battery (21) to at most an output upper-limit current (Ibout_lmt) when power is supplied to the motor (5) from the lithium ion battery (21) during a power running operation of the motor (5), and limits an input current into the lithium ion battery (21) to at most an input upper-limit current smaller than the output upper-limit current (Ibin_lmt) through the DC/DC converter (20) when regenerative power of the motor (5) is recovered into the lithium ion battery (21) during a regenerative operation of the motor (5).

Abstract: A double ended inverter system for an AC electric traction motor of a vehicle is disclosed. The inverter system serves as an interface between two different energy sources having different operating characteristics. The inverter system includes a first energy source having first operating characteristics associated therewith, and a first inverter subsystem coupled to the first energy source and configured to drive the AC electric traction motor. The inverter system also includes a second energy source having second operating characteristics associated therewith, wherein the first operating characteristics and the second operating characteristics are different, and a second inverter subsystem coupled to the second energy source and configured to drive the AC electric traction motor. In addition, the inverter system has a controller coupled to the first inverter subsystem and to the second inverter subsystem.

Abstract: Systems and apparatus are provided for an inverter system for use in a vehicle having a first energy source and a second energy source. The inverter system comprises an electric motor having a first set of windings and a second set of windings. The inverter system further comprises a first inverter coupled to the first energy source and adapted to drive the electric motor, wherein the first set of windings are coupled to the first inverter. The inverter system also comprises a second inverter coupled to the second energy source and adapted to drive the electric motor, wherein the second set of windings are coupled to the second inverter. A controller is coupled to the first inverter and the second inverter to achieve desired power flow between the first energy source, the second energy source, and the electric motor.

Abstract: A gate firing phase shift delay line technique is described for use in DC motor drive systems and is easily adaptable for controlling a plurality of electronically coupled power modules. A drive regulator is configured to produce a master gate firing timing signal for controlling the gate firing pattern of switching devices for a first power module. One or more delay blocks are configured to generate slave gate firing timing signals that are phase locked and identical but delayed in time with respect to the master signal. Each additional delay block is coupled to an additional power module having a set of switching devices controllable by the slave signals. The current output of each power module is summed via summing circuitry to deliver an output suitable to drive motors or other electrical loads in high power applications. The power modules can also be connected in series to combine (sum) the voltages for delivery to an electrical load.

Abstract: A controller able to efficiently operate an electric motor of an axial air-gap type as an electric motor and an electricity generator is provided.

Abstract: In a motor controller which supplies electric power to a motor of an electric power steering device from a main power supply and an auxiliary power supply, an N-channel MOS-FET is connected in parallel with a diode which is provided to prevent a sneak current from the auxiliary power supply to the main power supply. When electric power is supplied to the motor from the main power supply, the MOS-FET is turned on. Then, most of currents flow into the MOS-FET such that a power loss is reduced and a reduction in efficiency is prevented. The MOS-FET has high speed responsibility and excellent durability.

Abstract: A control device controlling a motor-driven four wheel drive vehicle, where either of front wheels and rear wheels are driven by an engine and the others are driven by an AC motor, is provided with an electric power generator driven by an engine to generate first three-phase AC power, a rectifier rectifying the first three-phase AC power, generated by the electric power generator, to second DC power and supplying the second DC power to a neutral point of the AC motor; and a first step-up and step-down inverter stepping up and converting the second DC power, supplied through the neutral point, to third three-phase AC power. The AC motor is rotationally driven by application of the third three-phase AC power from the first step-up and step-down inverter.

Abstract: The invention relates to an electromechanical braking system, especially for a motor vehicle comprising a 12V/14V on-board supply system. Said braking system comprises a brake actuator unit provided with an electric motor for generating a braking force, and a power supply for the electric motor, said power supply comprising a first electrical energy source, especially an accumulator of an on-board supply system. The power supply of the electric motor also comprises at least one capacitive energy source which is mounted in parallel to the first energy source. The invention further relates to an electromechanical braking system and a motor vehicle, especially a private car, comprising an electromechanical braking system.

Abstract: A propulsion system for a fuel cell hybrid vehicle that includes a fuel cell system and an EESS, where the propulsion system employs an algorithm for increasing system efficiency. A power limit value is defined as the maximum system efficiency times the charge/discharge efficiency of the EESS. If the vehicle operator requests a power greater than the power limit value, then the fuel cell system will preferably provide the power, and if the power request from the vehicle operator is less than the power limit value, then the EESS will preferably provide the power. The algorithm also considers changing operation conditions and parameters that impact the fuel cell system efficiency and the electric energy storage system efficiency, such as the state of charge of the EESS and regenerative braking.

Abstract: An apparatus for supplying a power to a motor for driving a mechanism that conveys a cartridge of a storage medium includes an accumulating unit that accumulates a regenerative power generated by the motor in a capacitor; and an adjusting unit that adjusts, when the power is supplied to the motor, a ratio of power supply from a power source to power supply from the capacitor.

Abstract: A power conversion system for converting a dc voltage to a pulsed ac voltage includes a dc voltage source providing three or more electric potentials, and a switching circuit arranged to connect one of the potentials selectively to an output terminal. A controller produces a pulsed ac output voltage at the output terminal from the potentials of the dc voltage source by controlling an on time for connecting each of the potentials to the output terminal.

Abstract: A rain detection system generates an operation signal for operating a wiper system on a window based on a detected window condition. The rain detection system includes a detection mechanism for intermittently detecting an amount of liquid on the window, a calculation mechanism for calculating an increase rate of the amount of the liquid detected in a detection operation by the detection mechanism and a determination mechanism for determining the window condition based on the increase rate calculated by the calculation mechanism. The determination mechanism distinguishes difference between condensation on the window and rain based on the detected liquid on the window.

Abstract: In a portable electronic device having a data-storage drive that employs a rotatable data-storage carrier, as the data-storage carrier undergoes spin-up and spin-down cycles when the data-storage drive is being accessed, the electronic device recaptures at least a portion of the kinetic energy of the rotating data-storage carrier during the spin-downs to generate electrical currents and use them to either charge the battery or reduce the battery drain.

Abstract: In a discharge control section of an inverter control device, when the connection of the battery and the smoothing capacitor is disconnected by means of a contactor, the charge accumulated on the smoothing capacitor is discharged by applying high-frequency voltage to the stator windings of the motor by controlling the main inverter circuit.

Abstract: A motor controller includes a position sensing device having a position sensor that senses a magnetic pole of a motor, a driver for driving the motor, and a wiring section that feeds a power supply voltage from the driver to the position sensing device. The position sensing device is equipped with a superposed-wave transmitter coupled to a first end of the wiring section and a serial converter for converting a signal of the sensing device into a serial signal. The driver is equipped with a superposed-wave receiver coupled to a second end of the wiring section and a parallel converter for converting the serial signal into a parallel signal. The foregoing structure allows superposing the information about switching a phase-excitation for driving the motor onto the wiring section formed of a pair of cables, i.e. two cables, so that the information is transmitted.

Abstract: A remotely configurable motor controller system comprises a motor controller and a remote configuration device. The motor controller includes solid state switches for connection between an AC line and motor terminals for controlling application of AC power to the motor and a control circuit for controlling operation of the solid state switches. The control circuit comprises a programmed processor for commanding operation of the solid state switches and a memory connected to the programmed processor storing configuration information relating to operation of the solid state switches. A wireless communication interface is operatively connected to the programmed processor.

Abstract: When digitizing a voltage, a capacitor is charged, through an impedance, to a voltage value (Um) dependent on the voltage to be digitized. The limits of that one of a plurality of voltage ranges in which said voltage value (Um) lies, are ascertained, and the two limits of that voltage range are defined as a first limit and second limit; the voltage at the capacitor is modified to the first limit by a charge modification circuit containing an impedance, and a first time interval needed therefor is identified; the voltage at the capacitor is modified to the second limit; the voltage at the capacitor is modified from the second to the first limit via the charge modification circuit. A seond time interval needed therefor is identified. Based on values of the first time interval and second time interval, a digital value is calculated, which serves as an indication of how much the voltage value (Um) at the capacitor differs from one of said two limits.

Abstract: A drive unit for vehicles prevents the rise of temperature of a high-pressure battery or condenser and assists the vehicle engine using a motor activated by an electric current supplied from the battery. The drive unit includes a battery temperature sensor and battery ammeter sensor, and defines the permissible current value of input-and-output current, which is limit of a current value to be inputted-and-outputted with respect to the battery, based on the difference between the battery temperature and the upper limit. When the battery temperature exceeds the threshold temperature, the permissible current value is set. Moreover, when the exchanged current value of the output-and-input current exceeds the permissible current value, the motor gradually decreases the output command value.

Abstract: A method controls an electric vehicle which is so constituted as to drive a synchronous motor by way of a switch and an inverter circuit. A battery acts as a source of driving a controlling power. The synchronous motor has a permanent magnet acting as an outer rotor. The method includes the following operations of: 1) detecting that the electric vehicle has an acceleration signal of zero; 2) detecting that an actual speed of the electric vehicle is less than a predetermined percent of a rated speed; 3) supplying a current to a winding of a fixed phase of the synchronous motor, by way of the inverter circuit; and 4) generating a braking force.

Abstract: A motor controller system (15a) for dc power source motors (10) which includes a sensor device (16) that operates to measure and generate a voltage signal from the motor current and the rate of change of said current, and a programmable input/output processor (12) which receives voltage signals as input from the motor current, dc power source (11) and/or motor (10) and compares on or more of these voltage signals to one or more control parameters. Based upon these comparisons, the processor (12) generates a pulse width modulation control signal, which triggers a switching mechanism (14) and related interrupt service routing to make adjustments to the operational parameters of the motor by periodic interruption of the motor current.

Abstract: A remotely configurable motor controller system comprises a motor controller and a remote configuration device. The motor controller includes solid state switches for connection between an AC line and motor terminals for controlling application of AC power to the motor and a control circuit for controlling operation of the solid state switches. The control circuit comprises a programmed processor for commanding operation of the solid state switches and a memory connected to the programmed processor storing configuration information relating to operation of the solid state switches. A wireless communication interface is operatively connected to the programmed processor.

Abstract: An automatically controlled DC power supply output circuit includes an isolation diode connected in series between the power supply and the load, a terminal voltage detection circuit connected in parallel between the power supply and the load on the load side of the isolation diode, and a shunt resistor connected in parallel between the power supply and load on the power supply side of the isolation diode. A control element such as a switch or variable impedance is connected in series with the shunt resistor to cause the shunt resistor to shunt current from the power supply when the terminal voltage detection circuit detects that the terminal voltage exceeds a predetermined threshold, for example due to stored voltage in case the load is a battery, secondary cell, or capacitor, or due to counter EMF generated by the load in case the load is a DC motor, thereby reducing the power supply output voltage to compensate for the detected increase in terminal voltage.

Abstract: An input power control device for controlling the electrical power fed into the driven device from the power supply is provided. The power control device includes a driving device, a voltage detector, a current detector, a multiplier, and a power controller. The voltage detector detects the output voltage of the power supply, while the current detector detects the drive current fed into the driven device from the driving device. The multiplier multiplies the voltage signal and the current signal together to obtain the present electrical power input to the driven device. If the present input power of the driven device is too high, the power controller outputs an adjustment signal to the driving device to decrease the drive current of the driven device until the input power is equal to the rated value.

Abstract: A direct-current power supply (40) is connected between the neutral points of two three-phase coils (24, 26) of a 2Y motor (22) constituted of the windings of the two three-phase coils (24, 26), which are connected in Y-connection and wound on a same stator, and to which three-phase alternating current power is severally supplied with a phase difference of a shifted angle between the windings from two inverter circuits (30, 32) having a positive pole bus (34) and a negative pole bus (36) for common use. A capacitor (38) is connected between the positive pole bus (34) and the negative pole bus (36). The electric potential difference between the neutral points of the three-phase coils (24, 26) is made larger or smaller than the voltage of the direct-current power supply (40) through the switching control of the inverter circuits (30, 32). Thereby, the capacitor (38) can be charged or discharged. Consequently, an inverter input voltage can be adjusted within a wide range.

Abstract: In order to be able to operate variably and in particular in an optimised manner in a large domestic appliance not only the main drive (17) thereof but also the auxiliary drive (24) thereof, without having to substantially increase the overall control complication and expenditure of the appliance required for that purpose, the main and auxiliary drives (17, 24) are fed from the same dc voltage intermediate circuit (19) which is provided only once, by way of change-over switch sets (12), by half-bridge circuits (21, 21′).

Abstract: Disclosed is a circuit and method for preventing erroneous opening and closing caused particularly, by use of a DC motor in an automatically/manually foldable portable radio terminal having a main body and a sub-body rotatable with respect to the main body. In the circuit, a motor provides rotating force to automatically raise or lower the sub-body, a motor driver drives the motor according to a motor driving direction control signal, an inverse electromotive force eliminator eliminates inverse electromotive force by opening or shorting both terminals of the motor according to an automatic mode or a manual mode, and a motor power controller controls supplying a driving power voltage to the motor. In the method of operating a folder, it is determined whether an automatic folder operation key has been pressed. Upon receipt of the automatic folder operation key input, a rectifier is turned on to open both terminals of a motor. At the end of the opening of the motor terminals, the motor is driven.

Abstract: A method of digitizing a voltage comprises the following steps: A capacitor (80) is charged, through an impedance, to a voltage value (Um) dependent on the voltage to be digitized; that one of a plurality of voltage ranges in which, i.e. the limits between which, said voltage value (Um) lies, is ascertained, and the two limits of that voltage range are defined as a first limit and second limit; the voltage at the capacitor (80) is modified to the first limit by means of a charge modification circuit containing an impedance (84), and a first time interval (T1) needed therefor is identified; the voltage at the capacitor (80) is modified to the second limit; the voltage at the capacitor (80) is modified from the second to the first limit via the charge modification circuit. A second time interval (T2) needed therefor is identified.

Abstract: For their pump drive dishwashers are usually equipped for reasons of cost only with an unregulated asynchronous motor which however is temperamental in terms of the sealing requirements involved, and a simple controller operating circuit (13) for executing the functional program because a rotary speed-controllable drive could not comply with the price limit which is preset by the market. However rotary speed control would be highly desirable in terms of the level of efficiency, energy demand and the generation of noise. In order to embody a dishwasher with a pump drive which involves a low level of wear and which is controllable in respect of its rotary speed without a substantial increase in cost, the use of a dc motor (11) with field windings (19) which can be alternately supplied with current by way of sensor-controlled switching sections (34) is an optimum.

Abstract: The wheel brakes of each vehicle axle or side or diagonal are supplied with current by a separate voltage source. To reduce the load on the vehicle's electrical system, the wheel brakes of a front axle are supplied with current first, and then the wheel brakes of a rear axle are supplied with current.

Abstract: An interconnection system (100) for transferring power between a first grid (22) operating at a first electrical frequency and a second grid (24) operating at a second electrical frequency includes a rotary transformer (102) and a power recovery system (103). The power recovery system (103) recovers and applies to the transferee grid a power differential attributable to mechanical power channeled to a rotatable shaft (113) of the rotary transformer (102).

Abstract: A motor driving apparatus PWM-controls a DC voltage from a rectifying unit according to a rotation speed setting information, and drives a motor by voltage pulse chooped by PWM. The rectifying unit is controlled so that a full-wave rectification is performed when the motor runs at a rotation speed below a prescribed rotation speed and a voltage-doubler rectification is performed when the motor runs at a rotation speed above the prescribed rotation speed. On the other hand, in case a motor drives a compressor of an air-conditioning system, the rectifying unit is controlled so that the full-wave rectification is performed when the air-conditioning system is a cooling operation and the voltage-doubler rectification is performed when the air-conditioning system is a heating operation.

Abstract: The present invention utilizes batteries in series addition and through controlled switching maintains current and voltage more constant as the batteries power a consuming device. The invention is described in its application to an electric motor powered wheeled vehicle and includes sensing means at the vehicles accelerator pedal and computer control to automatically control the power from a battery storage system to the electric motor efficiently and extend longevity of a battery powered vehicle.

Abstract: The microprocessor based controller for the fractional horsepower actuator motor includes a capacitive power backup system. The motor is used as an actuator and is coupled to an air damper or valve. In the event of a loss of power to the controller, the controller must drive the air damper or valve to a predetermined, failsafe position. The capacitive energy source stores sufficient power to drive the motor and the coupled air damper or valve to the predetermined failsafe position. The controller includes a sensor for determining the presence or absence of power and generating a failsafe control signal. A switch receives the failsafe control signal and passes power from either the main power supply or the capacitive energy storage unit. The controller includes a microprocessor and a memory. During a failsafe operation, the microprocessor drives the motor and hence the air damper or valve to the failsafe position at full power.

Abstract: A battery load leveling arrangement for an electrically powered system in which battery loading is subject to intermittent high current loading utilizes a passive energy storage device and a diode connected in series with the storage device to conduct current from the storage device to the load when current demand forces a drop in battery voltage. A current limiting circuit is connected in parallel with the diode for recharging the passive energy storage device. The current limiting circuit functions to limit the average magnitude of recharge current supplied to the storage device. Various forms of current limiting circuits are disclosed, including a PTC resistor coupled in parallel with a fixed resistor. The current limit circuit may also include an SCR for switching regenerative braking current to the device when the system is connected to power an electric motor.

Abstract: The invention provides a hybrid drive arrangement, particularly for a motor vehicle, having an internal combustion engine, a generator, a rectifier, an inverter, an energy accumulator connected to the direct current line between the rectifier and the inverter as well as a driving motor coupled to the inverter. A bypass line bridges the rectifier--direct-current line--inverter path, and a switching element is provided to couple the driving motor with the generator selectively by way of the rectifier--direct-current line--inverse rectifier path on the one hand, or the bypass line on the other.

Abstract: A motor controller includes a power source VG for driving a motor 1, a power source VRG for regenerating energy generated in the motor 1, and a power converter for transferring energy from the power source VRG to the power source VG. Windings of the motor are connected, at their opposite ends, to the power source VG and collectors of transistors TR1 to TR3, respectively. Diodes D1 to D3 are connected to nodes of the windings and the transistors TR1-TR3 such that magnetic energy generated in the motor 1 is supplied to the power source VRG. This configuration enables the motor controller to have a reduced number of transistors for driving the windings, and the power sources to be effectively utilized. Further, the motor controller can use a discharge circuit of small power consumption type, which can reduce heat generated in the motor controller.

Abstract: A disk device, such as an optical disk or magnetic disk, for a computer is mounted on the computer or inserted in a slot in the computer. The computer or host device provides a power supply for the disk device that is used to drive the disk in rotation and power the seek operation for read and write. When the disk device is in an idle mode in which the disk media is not spinning, the disk(s) must first be driven to the access speed of rotation during a spin up or start of rotation time period. The current supplied by the external main power source for the computer provides the start current for the spindle motor that drives the disk(s) in rotation. An auxiliary power source provides an additional current that is added to the current provided by the main power source to decrease the time in which the start operation is executed or to ensure start up when only a limited amount of current is available from the main power source.

Abstract: Sub-excitation of a series-type excitation magnetic field winding for a DC motor or generator is provided by an auxiliary power supply which, when the voltage in the main circuit is low, supplies voltage through a diode to the main series field winding in order to keep the voltage at or near saturation and thereby improve motor efficiency.

Abstract: As a method for energizing a three-phase stepping motor of Y-connection, driving current values are set to be values resembling sine wave input approximation, thus making it possible to effect driving at small vibration. Energizing of the three-phase stepping motor is performed by a two-three phase driving scheme which calls for alternately effecting a two-phase excitation of the coils in the motor and a three-phase excitation of the coils in the motor. The driving current flowing through each of the coils approximates a sine wave having normalized values defined by .+-. 1, .+-. 0.87, .+-. 0.5 and 0.

Abstract: A control circuit for an electric motor is proposed, whose rate of rotation and rotational direction depends on a control signal (Ue) at the input terminal (10). The rotational direction is given by means of a determined control signal level being exceeded or fallen short of. The rate of rotation is controlled by means of a pulse width modulation of the control signal (Ue). There is a nonlinear relationship between the change in the pulse duty factor of the pulse width modulation and the control signal. The mean adjusting speed of an actuating motor accordingly adapts to the control deviation signal of an actuating control.

Abstract: The output frequency of a variable frequency power source for driving a motor which drives a rotary body such as a fan in a variable-speed control mode is fixed, when abnormality in a control signal supplied to the variable frequency power source from outside to determine the output frequency of the variable frequency power source is detected, at the output frequency of the variable frequency power source immediately before the detection of abnormality in the control signal, and thereby the abnormal variation of the revolving rate of the motor resulting from the abnormality in the control signal is avoided.

Abstract: A motor operated valve, typically a butterfly valve driven by .[.a synchronous.]. .Iadd.asynchronous .Iaddend.electric motor (16), is provided with a torque sensing arrangement wherein an cyclic electrical signal representative of the rotational speed of the motor is produced by magnets (22) on disc driven by the motor and Hall effect switches (23,24). The frequency of this signal is compared in a circuit (43) with the frequency of current supplied to the motor to provide an indication of motor torque. Switches (46,47) define preset torque limits for the valve. If the limits are exceeded, a signal is fed to control logic (41) which operates switches (18) to control the supply current to the motor. The speed signal from the Hall effect switches is also fed to a counter (31) to develop a count representative of movement of the valve. The output of counter (31) is compared with preset valves defined by switch circuits (37,38) to define limits of travel for the valve.