Abstract: A spring return rotary actuator incorporating a DC brush commutated electric motor and a pulse width modulation drive circuit which reduces the voltage at which current is supplied to the motor once a rotation sensor senses that the actuator output shaft has stalled. The drive circuit also includes a temperature responsive feature which increases the voltage at which current is supplied to the motor in the event a sensed temperature exceeds a temperature limit.

Abstract: The driver circuit (10) comprises a first triac or the like (11) for connection in series with the stator winding (5, 6) of the motor between the terminals (12, 13) of an alternating-current voltage supply, the gate of the first triac (11) being arranged for connection to an intermediate point (C) of the stator winding (5, 6) of the motor (M). A second triac or the like (15) is connected between the intermediate point (C) of the winding (5, 6) and the terminal (13) of the voltage supply to which the first triac (11) is connected. A control circuit (15-27) is connected to the gate of the second triac (15) such that, each time the motor (M) is connected to the voltage supply, it initially makes the second triac (15) conductive and consequently cuts off the first triac (11) for a predetermined initial period of time. and cuts off the second triac (15) and allows the first triac (11) to become conductive after this period of time.

Abstract: A movable barrier operator having improved safety and energy efficiency features automatically detects line voltage frequency and uses that information to set a worklight shut-off time. The operator automatically detects the type of door (single panel or segmented) and uses that information to set a maximum speed of door travel. The operator moves the door with a linearly variable speed from start of travel to stop for smooth and quiet performance. The operator provides for full door closure by driving the door into the floor when the DOWN limit is reached and no auto-reverse condition has been detected. The operator provides for user selection of a minimum stop speed for easy starting and stopping of sticky or binding doors.

Abstract: A method and apparatus for controlling a hybrid vehicle having an auxiliary power unit, at least one energy storage device, at least one electric drive motor for traction, and a controller with associated memory. The method initially involves the steps of acquiring data for the current vehicle operating state for a variable control interval and storing the vehicle operating state data as measured operating state variables. Simulated vehicle operating state data is generated by inputting the measured vehicle operating state variables into a simulation model running on-board in the controller memory.

Abstract: An engine-motor hybrid vehicle has a power transmission device including a first rotary electric machine and a second rotary electric machine. The first rotary electric machine has a first rotor connected to an engine and a second rotor connected to vehicle wheels. When the engine is in the idling condition, an electronic control apparatus controls the power transmission device to restrict engine vibrations from being transmitted to the vehicle. The electronic control apparatus controls the power transmission device based on a difference in timings of detecting a first rotor position and a second rotor position in the first rotary electric machine. The electronic control apparatus controls the power transmission device to reduce mechanical shocks which occurs immediately after engine operation starting.

Abstract: A method for starting a polyphase DC motor having a rotor. The position of the rotor is detected by initiating current in each of the phases of the motor and measuring a time period between the initiation of current in the coil and an instant when the current exceeds a threshold current. The phase in which the current reaches the threshold in the shortest amount of time is the phase closest to the position of the rotor. A phase closest to the position of the rotor is identified in each of an odd number of trials, and a starting phase is selected as the phase identified in the majority of trials. The motor is started by providing current to the starting phase.

Abstract: A system for low acoustic noise spindle motor commutation is disclosed. The system contains a control device that generates commutation control signals which cause spindle motor drivers to source or sink current through windings of a spindle motor. The windings create electromagnetic fields which induce rotational movement in a spindle motor rotor. Low acoustic noise snubber devices are coupled to each winding and are dynamically configurable by the control device to provide low spindle motor driver charging current upon initial application of power to the spindle motor, and reduced acoustic noise and back EMF-generated current and voltage surges at the spindle motor driver during spindle motor commutation.

Abstract: When torque control is performed for suppressing speed change within one rotation using a synchronous motor (6) controlled by an inverter (5) for a load having cyclic torque changing, an arrangement is employed which includes inverter control means (8) (10) for controlling the inverter (5) so as to superpose a changing amount upon an amplitude and phase of a current waveform or voltage waveform, so that torque control is realized for reducing low speed vibration of a cyclic intermittent load with maximum efficiency condition and with practical arrangement.

Abstract: A method of controlling the torque of a rotary machine powered by means of an inverter and servo-controlled by a system having sensors, an observer, and a computer which delivers controls to the switches of the inverter on the basis of values supplied to the observer by the sensors, in the form of sequences of three vectors to bring the torque &Ggr; and the stator flux &PHgr;S of the machine towards reference values for &Ggr;ref and &PHgr;Sref. The measurement sampling period is selected to be equal to the sequence period DTML which corresponds to half the switching period of the inverter.

Abstract: An apparatus for controlling an actuator in response to a target speed voltage signal, the actuator having a moveable member and having a coil that influences movement of the member. A first summing node is provided having a control output voltage, for summing or subtracting voltages applied thereto, as the case may be and receiving the target speed voltage signal at a first, summing input thereto. A proportional compensation unit is provided, receiving the control output voltage and providing as an output a proportionally compensated output signal. An integral compensation unit is provided, receiving the control output voltage and providing as an output an integrally compensated output signal. An inverse compensation unit is provided, receiving the target speed voltage signal as an input and providing an inversely compensated output signal having a voltage corresponding to the voltage of the target speed voltage signal multiplied by the inverse of a predetermined amplification factor.

Abstract: A commutation circuit for a sensorless three-phase BLDC motor enables soft switching in the commutation process without the need for a complex delay circuit and generates signals separate from the back EMF signals of the stator to start the rotation of the motor rotor. The commutation circuit includes a starting circuit adapted to generate a starting clock signal to forcibly start the motor without information associated with the position of the motor rotor and generates first, second and third reference clock signals that are used to drive the motor in constant velocity operation.

Abstract: An electric motor actuator used in an environment of varying loads for varying time periods is efficiently designed to a predetermined specification in terms of both motor load and time and operated up to but not exceeding this specification over the full expected operating range. A motor load signal is low pass filtered with a plurality of time constants spanning a range of expected motor operation to generate a plurality of filtered motor load signals each associated with one of the time constants. Each of these filtered motor load signals is compared with a predetermined reference value corresponding to the associated time constant. If one or more of the filtered motor load signals exceeds the predetermined reference value with which it is compared, the one that so exceeds by the greatest margin is selected. A command current limit factor is derived from the selected filtered motor load signal and used to limit the commanded motor current.

Abstract: A motor drive apparatus for driving a motor with power derived from a main power source, including a signal input device configured to input a start signal and a stop signal to initiate starting and stopping of the motor; a voltage regulator configured to output regulated electric power to the motor; and a semiconductor switching device disposed between the main power source and the voltage regulator, coupled to the signal input device, and configured to switch electric power from the main power source to the voltage regulator in accordance with the start signal input from the signal input device, and to shut off the electric power to the voltage regulator in accordance with the stop signal input from the signal input device.

Abstract: A method for the starting and steady-state supply of a permanent-magnet synchronous motor, particularly for driving a centrifugal hydraulic pump. The method comprises three successive steps: a first learning step, a second starting step, and a third steady-state step. During the first step, the rotor is turned through two angles of 180 mechanical degrees in the same direction, storing the parameters of the rotor and particularly determining the initial current and the mechanical zero point of the rotor. During the second step, by generating with a power supply (inverter) a practically sinusoidal current waveform, the rotor is started with a higher current than the stating current and with a low frequency which gradually increases, waiting for the rotor at its transit through 80, 100, 260 and 280 mechanical degrees. Once the intended steady-state speed has been reached, a practically sinusoidal current is applied and the rotor is waited for at transit through the zero points.

Abstract: A motor powered by a dc power source has a stator having a single phase winding. A power switching circuit of the motor has power switches for selectively connecting the dc power source to the single phase winding. A permanent magnet rotor in magnetic coupling relation to the stator drives a fan. A position sensor on the stator detects the position of the rotor and provides a position signal indicating the detected position. A control circuit including a microprocessor responsive to the position signal and connected to the power switching circuit selectively commutates the power switches to commutate the single phase winding as a function of the position signal. The microprocessor controlled motor is programmed to reduce operation at speeds at which resonance occurs and provides an alarm in the event that the static pressure of the air driven by the fan is unacceptable.

Abstract: A torque controller system provides improved torque distribution as a function of wheel diameter size in a vehicle propelled by electric traction motors. The system includes one or more torque processors each having a multiplier coupled to receive an input signal and configured to produce an output signal which is the product of the input signal and a variable multiplier value generated by a respective torque distribution generator based on a predetermined torque distribution control function.

Abstract: In control apparatus and method for an electric vehicle, when the motor is determined to be locked during a run of the vehicle on an ascending slope, a limitation torque .tau.r of the motor as a function of a maximum value T.sub.JMAX of estimated junction temperatures of respective switching devices of an inverter circuit is determined, an output torque .tau.L for the motor to be escaped from the locked state is calculated as .tau.L=.tau..GAMMA.-.DELTA..tau., wherein .DELTA..tau. denotes a displacement torque, .DELTA..tau.=.DELTA..tau.+A when .tau.r<.tau.c and a phase domain of the motor determined on the basis of a magnetic pole position .theta. is the same as the previous one and .DELTA..tau.=0 when .tau.r.gtoreq..tau.c and the phase domain is not the same as the previous one.

Abstract: The synchronizing circuit of a digital drive system of an electric motor is configured to function in a closed loop or in an open loop mode by adding a minimum number of elements to the normal scheme of a closed loop synchronizing circuit. In practice, by adding only one programmable register and a pair of two-input de-multiplexers, the system is able to automatically switch from one mode of operation to the other mode. The programmable open loop mode permits compensating for the phase angle between the current flowing through the windings and the drive voltage applied thereto, as in case of a voltage mode driving.

Abstract: The apparatus for controlling an electrical starter motor for cranking a cranking mechanism of an internal combustion engine to start the engine includes a circuit for making an electrical connection between a voltage source and the starter motor by which the starter motor is coupled with a cranking gear of the engine by means of a shiftable transmission when the circuit is energized and an electronic control unit for controlling at least one of a voltage, a current and an on-time of the electrical starter motor in a stepwise manner in a two-stage control process including a first stage in which the starter motor is coupled with the cranking gear and operated at a reduced rotation speed to reduce wear. The electronic control unit is electrically connected between the voltage source and the starter motor and is an electronic relay that includes a central processing unit and at least two electronic power switches for switching the voltage of the starter motor.

Abstract: A circuit arrangement for cycled control of a motor, includes an overload detection device which has a signal sensing stage. Reliable detection of a motor overload is achieved, substantially without losses in the electronic system and with an economical configuration, by the fact that the overload of the motor can be sensed by way of the signal sensing stage by picking off a voltage peak which occurs at a circuit inductance.

Abstract: The invention relates to a switching device for the manual drive of an electromotive actuator for the control of fittings. In order to connect the manual drive by means of few components, whilst ensuring a simple design, the operative connection between the drive motor and the power take-off being maintained during manual drive, a drive shaft stub of the axially fixed drive shaft is equipped with a radial coupling pin. The handwheel shaft is mounted axially displaceably and in alignment with the drive shaft. That end of the handwheel shaft which is located opposite the handwheel is equipped with a coupling sleeve displaceable axially counter to the force of a compression spring. That end of the coupling sleeve which faces the drive shaft has a groove, the entrance of which is widened on both sides by means of run-on slopes.

Abstract: The driver circuit (10) comprises a first triac or the like (11) for connection in series with the stator winding (5, 6) of the motor between the terminals (12, 13) of an alternating-current voltage supply, the gate of the first triac (11) being arranged for connection to an intermediate point (C) of the stator winding (5, 6) of the motor (M). A second triac or the like (15) is connected between the intermediate point (C) of the winding (5, 6) and the terminal (13) of the voltage supply to which the first triac (11) is connected. A control circuit (15-27) is connected to the gate of the second triac (15) such that, each time the motor (M) is connected to the voltage supply, it initially makes the second triac (15) conductive and consequently cuts off the first triac (11) for a predetermined initial period of time, and cuts off the second triac (15) and allows the first triac (11) to become conductive after this period of time.

Abstract: A motor controller includes an input terminal (22), a frequency selective network, a first controller, and a second controller. The input terminal is adapted to be coupled to a drive phase of a motor (16) for receiving a signal (24). The frequency selective network (18) has an input coupled to the input terminal (22) and an output for providing a first signal representative of the back EMF signal within a frequency range corresponding to a predetermined harmonic frequency above a primary frequency thereof. The first controller (20) has an input coupled to the output of the frequency selective network (18) and an output for providing a second signal representative of a position or a velocity of a rotor of the motor (16). The second controller (10) has an input coupled to the output of the first controller (20) and an output for providing a third signal. The third signal indicates how the motor (16) is to be driven.

Abstract: An electric power steering circuit assembly comprises a heat sink, a power circuit board secured in close contact with the heat sink, mounted with large-current parts, and having connecting members erected thereon, a housing mounted with large parts and secured to the heat sink so as to cover the power circuit board, a control circuit board mounted with control components and secured to the housing so as to overlap the power circuit board in the vertical direction, and guides disposed on the housing for receiving the connecting members to position the housing relative to the power circuit board.

Abstract: A motor control processor controls motor spin-up in a disk drive by detecting environmental temperature at the spindle motor of the disk drive, controlling commutation phase advance to generate substantially maximum torque if the detected environmental temperature indicates that maximum torque is needed, and adjusts the commutation phase advance for optimal efficiency after the maximum torque is no longer needed. Following motor start and reaching operational speed, the motor is operated in a steady-state maximum operating efficiency mode unless sensed environmental temperature indicates that maximum torque, rather than maximum efficiency, is needed. The system determines that the need for maximum torque has passed either when a predetermined time interval after motor start expires or by repeatedly polling motor temperature information.

Abstract: A motor control system uses predictive signal processing techniques to estimate the value of the next motor torque request or command from a controller within a brake-by-wire system, then adjusts the control of the electric motor that applies pressure to actuate the brake calipers.

Abstract: Method for measuring the output torque of an asynchronous motor having a stator and a rotor comprising the steps of measuring the rotational frequency of the stator field of the motor, the rotational speed of the rotor, calculating a measurement value for the slip speed from the difference between the rotational speed of the rotor and rotational frequency of the stator field, and calculating a measurement value for the output torque form the slip speed and statistical performance characteristic values for the output torque intrinsic to the motor.

Abstract: An apparatus for controlling an actuator having a moveable member and having a coil that influences movement of the member, by provision of a drive current to the coil in response to a target speed voltage signal. The invention includes an up/down counter, counting at a predetermined count rate and providing a count output. A control unit is provided for controlling the direction of count of the up/down counter depending on whether the voltage across the coil, sensed periodically a first predetermined interval after the drive current to the coil is interrupted, is greater than, or less than, a reference voltage having a predetermined relationship to the target speed voltage. A digital-to-analog converter is provided, responsive to the count output to provide a compensated voltage signal having a voltage corresponding to the count output.

Abstract: A pump motor control apparatus is adapted to control a pump motor of a forklift truck by using a driving transistor connected between a battery and the pump motor. The pump motor control apparatus includes a current detection circuit for detecting a current flowing through the pump motor to generate a current detection signal representing the current. A controller is employed to determine the load condition based on the current detection signal to thereby generate a control signal for use in the control of the driving transistor. The control signal is a pulse width modulation signal whose on-duty ratio is controlled depending on the load condition so as to decrease the torque and speed of the pump motor during the unloaded condition but to increase the torque and speed of the pump motor during the loaded condition.

Abstract: An electric motor vehicle comprises as a drive system a battery, a motor, and a controller for controlling the rotation of the motor. The electric motor vehicle disposes an accelerator for controlling speed of the motor, a key switch for turning on or off the motor and the controller, a circuit for judging an opening/closing state of the accelerator when the key switch is turned on, and a circuit for preventing the rotation of the motor when the key switch is turned on with the accelerator open.

Abstract: A system and method for evaluating the effectiveness of a tractive effort maximizing control system in a wheeled vehicle utilizes a process of operating the vehicle by applying controlled power to at least some wheels of the vehicle to enable motion of the vehicle, disabling the tractive effort maximizing control system, and varying creep speed between a minimum value and a selected maximum value while monitoring the tractive effort to identify a maximum available tractive effort. Thereafter, the tractive effort maximizing control system is enabled and the resulting tractive effort developed by the vehicle measured. Comparing the resulting tractive effort to the maximum available tractive effort produces a measure of effectiveness of the tractive effort maximizing control system.

Abstract: In a method for operating a brushless motor with commutated stator excitation and permanent rotor field, the stator is initially energized partly. Depending on the polarity of the back electromagnetic force (EMF) in the non-energized stator coil at a predetermined time point (t(n)+T.sub.OFF) and on the occurrence of a EMF zero-crossing event in a following time frame (T.sub.MONITOR), the next stator commutation (t'(n+1)) is scheduled. Thereby, three cases (i)(ii)(iii) are distinguished and detected events (.tau.(n-1)) in previous commutation cycles (n-1) are taken into account.

Abstract: A method of detecting the angle of rotation of a DC motor includes the steps of: driving the DC motor with a predetermined torque for a predetermined period of time which is selected so that the angular acceleration of the DC motor is substantially constant during the above period of time; and calculating the angle of rotation of the DC motor from the driving time period and the voltage generated by the DC motor after the driving of the DC motor is stopped. This method makes it possible to accurately detect the angle of rotation and the load torque using an apparatus having a simple structure.

Abstract: To provide a controller of an electric power-steering system, capable of improving the steering performance by presuming a motor angular speed .omega. in a range in which the angular speed of a motor is small and moreover very accurately presuming the motor angular speed and thereby, completely showing the functions for compensating the inertia of the motor and controlling the astringency of a vehicle. Because the presumed error of a back electromotive force between a model motor and a motor to be actually mounted is proportional to a motor current, a dead zone of a motor angular speed having a width proportional to a motor current is set to the presumed value of the motor angular speed. When the motor current is small, the width of the dead zone also decreases. Therefore, it is possible to presume an angular speed .omega. even in a region where the motor angular speed is small.

Abstract: A drive current and a regenerative current are alternately applied to a motor during a PWM (pulse width modulation) time period. The regenerative current is produced by an electromagnetic induction of an armature and flows in the opposite direction as the drive current. Therefore, a rotating speed of the motor is reduced, so that a speed-reduction following characteristic for the motor is improved. By varying the duty factor, the lengths of time during which the drive current and the regenerative current are flowing can be controlled. Thus, the speed of the motor can be controlled.

Abstract: A method for determining the active power (P) of asynchronous electric motors of winning and conveying equipment in underground mining. According to the invention, particularly easy and accurate determination of the instantaneous active power of the motors is obtained by storing the individual motor characteristic (P(n); M(n)) of each motor in a computer, by detecting the instantaneous speed (n, n') of the motor with the aid of a tachometer and by comparing this speed with the characteristic stored in the computer, the active power being derived from the torque value or power value assigned to the detected instantaneous speed, as stored in the computer. This particularly rapid and simple calculation of the power value does not require any readings to be taken at the power supply to the motors.

Abstract: A starting assistance device for a vehicle has an electric motor and a dog clutch which is switched on at the time of starting of the vehicle to thereby transmit a torque to idler wheels. A sensor is provided to detect the switching on and switching off of the dog clutch. In case the switching off of the dog clutch is not detected when the rotational speeds of the idler wheels have exceeded a predetermined value after the starting of the vehicle, the electric motor is driven in such a direction of rotation so as to cancel the torque which operates on the dog clutch due to the frictional force in the electric motor.

Abstract: In a method of controlling a direct-current drive, in particular a directrrent door drive, two state variables of the direct-current drive are determined and, on the basis of these state variables, a load or resistance moment applied to the direct-current drive is determined and compared with a predetermined load or resistance moment. Subsequently, it is established that an abnormal situation exists when the load or resistance moment determined exceeds the predetermined load or resistance moment.

Abstract: A control apparatus for an asynchronous machine, in particular as a drive for electric vehicles, is equipped with an incremental transducer for the rotation speed of the asynchronous machine and a torque setpoint transducer, the signals of which can be delivered to a setpoint-value entry device in order to generate setpoint values (three-phase reference sine-wave system) for a closed-loop-controlled inverter or inverter power section to operate the asynchronous machine. The setpoint-value entry device contains means for defining at least the rotor frequency (slip frequency) and the amplitude as a function of the desired torque setpoint value. The setpoint-value entry device contains a summing device for adding or subtracting the rotor frequency to or from the mechanical rotation frequency, corresponding to the rotation speed, of the asynchronous machine as a function of the instantaneous rotation direction, the desired rotation direction, and the direction of the desired torque.

Abstract: A system that limits the torque of motors and discontinues motion control activity of system components in order to protect electrical and mechanical system hardware. Mechanical stresses are controlled by a microprocessor in a manner that they will not exceed predefined limits so that mechanical components will not be destroyed. Thus, replacement of major system components such as drive electronics and fuses may be avoided. Hence, there will be a reduction in service calls to repair the motors and system components.

Abstract: A driving controller of electric vehicles. An angular accelerative dimension error calculator calculates error information having a dimension of angular acceleration of a car body. A feedback torque calculator calculates the feedback torque on the basis of the error information according to the sign of a steering angle and the error information, and ON/OFF of an accelerator. A vehicle controller corrects the reference torque, determined according to an accelerator angle and braking force, by the feedback torque, and outputs the corrected reference torque toward motor controllers, thereby improving vehicle running safety.

Abstract: The sensing of the rotor position for synchronizing the drive of a multi-phase brushless motor when driven in a "multi-polar" mode is carried out by interrupting the driving current in at least one of the windings of the motor coupled with a zero-cross sensing circuit of the BEMF signal. This done by using a first logic signal, enabling a logic gate for asserting a zero-cross event detected by the circuit by a third logic signal, and simultaneously resetting the first signal and the third signal after a certain period of time from the instant of interruption.

Abstract: Torque ripples of a motor having interior permanent magnets can be reduced through the following method and the torque ripple controller using the same method: first, drive the motor having a plurality of phase windings and interior permanent magnets with a basic current supply circuit which outputs a basic current having a predetermined waveform, then store torque ripple waves produced in the running motor or obtained through a numerical analysis into a torque-ripple-wave-memory, next, compensate the torque ripple wave tapped off from the memory according to a prepared torque ripple compensation pattern and transform it to a torque compensation waveform with a torque-compensation-waveform-producing-circuit, further, multiply the torque compensation waveform tapped off from the waveform producing circuit by the basic current with a multiplier to output a torque ripple control current, and, supply the torque ripple control current to the plurality of phase windings shifting a phase by a predetermined electrica

Abstract: A motor direction control device id used for electromotive vehicles which has an electric motor adapted to cause the vehicles to move forwards and backwards. The motor direction control device includes a direction control level shiftable from a neutral position into forward or reverse position. Operatively connected to the direction lever is an elongated pliable strip which is slidable along a predefined moving way by the shifting operation of the direction control lever and carries a permanent magnet. First and second magnetolectric sensors are arranged in a spaced-apart relationship with each other along the moving way of the elongated strip, each of the magnetoelectric sensors capable of generating, when left deactivated, a position signal of first logic level and activatable by the permanent magnet to produce a position signal of second logic level as the direction control lever is shifted into the forward or reverse position.

Abstract: A method and a device for operating an asynchronous machine include controlling the rotor and the stator of the machine during start-up with respective first and second direct converter units. After the start-up the second direct converter unit is isolated from the stator and is connected to the rotor in parallel with the first direct converter unit. Therefore, direct converter units which are already available for performing a mains operation are used during start-up.

Abstract: A control command value map is formed with a voltage applied to a motor and an output torque as an output command value from a driver being taken on axes of coordinates, so that an output command value suitable for a power source voltage is easily and rapidly provided regardless of a variation in voltage of a motor driving power source by applying an output command value determined from the control command value map from an output command value determining means to a driving means. The motor can be driven based on such output command value.

Abstract: This disclosure describes an improved electrical power apparatus for assisting a rider in powering a wheeled vehicle such as a bicycle. The apparatus controllably connects a rechargeable battery to a dc motor engageable with a wheel of the vehicle in a predetermined fashion, such that the wheel is driven with a torque that varies with the vehicle's speed according to a predetermined non-uniform profile. This control advantageously can be achieved by modulating on and off a switch at a duty cycle between 0% and 100%, which is selected to provide a motor torque that decreases monotonically with the vehicle's speed, from a maximum value at zero speed to a predetermined intermediate value at a predetermined intermediate speed, and that remains at that predetermined intermediate value for speeds between the intermediate speed and a predetermined maximum speed. The apparatus further includes a charger for charging the battery using a flyback-type dc-to-dc converter.

Abstract: An electric power steering apparatus includes a controller for controlling power assist of an electric motor so as to reduce a manual steering force required of the driver. The controller includes two closed control loops, one operating on the basis of a steering torque and the other on the basis of a differential value of the steering torque. The second closed control loop includes a differential torque compensator for compensating for the differentiated steering torque in such a manner as to increase the proportion of an assist torque developed in accordance with the change of the steering torque while keeping a desired degree of stability of operation of the steering system.

Abstract: A method of preventing a wire from becoming entangled in a reinforcing bar fastening machine having a wire feed device for feeding a wire for fastening reinforcing bars, a guide arm for guiding the wire so as to wind around a crossing point of the reinforcing bars in the form of a loop, a twisting device for performing a tying operation by twisting while picking up part of the loop of the wire wound around the crossing point of the reinforcing bars, and a cutting device for cutting the loop from the wire on a reinforcing bar fastening machine side, the method comprises the steps of: monitoring a torque of a motor for driving the twisting device; and stopping the operation of the twisting device when no increasing tendency is observed in changes in the torque after a predetermined time has elapsed from an operation start timing of the twisting device.

Abstract: A method for the control of a load, such as a motor, by means of a start-up controller (1) connected, on the one hand, to a fixed frequency alternating supply, and, on the other hand, to the motor, and including static switches associated with at least one phase of the motor and operated by a control circuit (2), characterized in that the electromagnetic torque (C.sub.m) of the motor is automatically controlled to a variable reference value (C.sub.cons) in the start-up or deceleration stage of the motor.