Abstract: A system having two or more A.C. motors driving the same load. The stator windings and rotors of both motors each conduct current having a vector representative of a magnitude and angular position of the current in the respective rotor and stator winding. Stator current sensors are provided for producing an indication of the magnitude of the stator current vector to each motor. Encoders are provided for sensing the rotating speed of each of the rotors from which can be calculated the angular position of the rotor load current vector with respect to the rotating stator flux current vector. A first torque control controls the magnitude of the stator current of a first one of the motors such that the stator flux current vector of the first motor and the rotor load current vector of the first motor are angularly separated by 90.degree.. This angular relationship produces maximum torque at the rotating speed of the first motor.

Abstract: A three phase motor conversion and monitoring circuit converts a three phase motor to be started and run on single phase line power. During motor start-up, the circuit connects a start capacitor across a first input pair of the motor via a normally closed relay contact. The circuit includes a power supply connected across a first motor input pair which powers both a voltage monitor connected across a different input pair and a phase sequencing detector. When normal run voltage is detected across the first and second input pairs, and if and only if the phase sequencing detector has detected a normal phase sequence indicating that the motor is rotating in the correct direction, the relay is operated to open the normally closed contacts and to remove the start capacitor from the motor circuit.

Abstract: A method for determining the real power of an electrical drive, preferably an electrical fitting drive, includes subtracting an ohmic or resistive power loss in a stator of the drive from a measured real power. It is intended that an ohmic or resistive power loss in a connecting line of the drive also be subtracted. A device for determining the real power of an electrical drive includes line pairs each connecting two connecting lines remotely from the drive, to a DC voltage source. A known ohmic or non-reactive resistor is inserted into one of the lines in each case. Each of the lines is connected on the side of the ohmic or non-reactive resistor facing toward the drive, through a voltmeter, to the other line. The voltmeters are connected to an evaluation unit.

Abstract: An automatic firing arrangement (1) has an apparatus for actuating a fan which is driven by a controllable-speed asynchronous motor (2). The apparatus includes a frequency converter (3) with which the speed of rotation of the asynchronous motor (2) is controllable, switching devices (6.1; 6.2; 6.3) by which the asynchronous motor (2) can be temporarily separated from the power supply for a predetermined period of time, and a measuring means (5) with which the speed of rotation and the direction of rotation of the asynchronous motor (2) can be detected by way of the generator action thereof in said period of time.

Abstract: A positional deviation reading sampler reads or samples a positional deviation between a target position inputted from an external device and an actual position of a motor. A position control calculator converts the positional deviation into a speed command. A speed control calculator receives a speed deviation between the speed command and an actual speed, and converts this speed deviation into a torque command to drive the motor. The position control calculator, having a function of switching a sampling interval in accordance with a level of the positional deviation, determines an optimum sampling interval for the positional deviation reading sampler. The speed control calculator performs the open-or-close control of the sampler in such a manner that the sampling interval of the positional deviation reading sampler is reduced with reducing positional deviation.

Abstract: A variable speed pumping up generator includes a first speed control unit for outputting a rotating speed command signal for controlling a pump turbine in accordance with a power output command and outputting an excitation control signal to an AC excitation unit of the generator, and a second speed control unit for controlling, in a generation mode, an amount of AC excitation from an AC excitation unit when a rotating speed of a rotary shaft departs from a lower limit setting or an upper limit setting. The setting is set in accordance with the rotating speed generated during a normal operation.

Abstract: A starting device for single phase induction motors having a start capacitor is effective to disconnect the start capacitor at a desired motor speed in response to a specific phase relationship between the voltage across the main winding and the voltage across the start winding. The specific phase relationship is a condition wherein a phase angle defined by the phase relationship reverses from a decreasing value to an increasing value.

Abstract: Polarity change of a feed-forward compensation signal for compensating for a dead-time voltage disturbance is synchronized with zero crossings of a load current reference. The load current reference is advanced in time by adding a fixed phase angle, scaled by the synchronous frequency, to the synchronous coordinates angle. The load current reference is time-advanced only for timing the polarity change of the feed-forward compensation signal and not for application to the current regulators; the current regulators still use the load current reference (unadvanced). For a converter, the load current would be an AC mains input current. For an inverter, the load current could, for example, be an induction motor stator current. The shape of the feed-forward compensation signal is approximately trapezoidal and is obtained from the limited, amplified, advanced load current reference.

Abstract: The disclosure involves a drive system having a control section, an adjustable frequency drive unit coupled to the control section, and first and second drive motors. The drive system is used with a material handling machine such as a light-duty crane on which any two of the hoist, bridge and trolley drives are rarely used simultaneously and in any event need not be used simultaneously. The drive unit is a scalar or flux vector (feedback-type) inverter and is the sole drive unit providing electrical power to the drive motors. Preferred control is by a pendant station or radio transmitter. Operating a pushbutton on the pendant station (or a paddle-like stick control on the transmitter) for a particular drive motor "locks out" operation of the other motors. Motors are operated on a first-come, first-served basis.

Abstract: A powered medical instrument includes a manually operable foot switch coupled to a motor control unit which in turn is coupled to an autoclavable handpiece containing a brushless sensorless electric motor driving a tool. The motor control arrangement includes a control panel through which a user can select a maximum torque value for the motor, and includes a torque limit circuit which limits the motor torque to the torque limit value selected by the user. The control panel also provides a digital display of actual motor speed and allows the user to digitally specify a maximum motor speed. The output of the foot switch is adjusted by a transfer function and then used to control motor speed, and the transfer function is adjusted as necessary to precisely conform the actual motor speed and thus the displayed speed to the selected maximum speed.

Abstract: An apparatus for controlling an elevator capable of providing enhanced comfort to passengers by reducing and compensating for propulsion change and propulsion ripples, the apparatus comprising an acceleration sensor for detecting the moving acceleration of an elevation member, and a control circuit including a speed controller for generating an acceleration command to be issued to the elevation member in accordance with a speed deviation. An acceleration controller for generating a corrected propulsion command to be issued to the elevation member in accordance with an acceleration deviation between the acceleration command and the moving acceleration is provided and a electric power command generater for generating an electric power command to be issued to the inverter in accordance with the corrected propulsion command is also provided.

Abstract: A method of controlling the commutation of power to an electric motor back EMF sensing or Hall effect sensors is disclosed. At least part of the current waveform is sensed in at least one motor winding and is used to establish information relating to the appropriate commutation pattern required to commutate power to the motor and control motor parameters e.g. motor speed.

Abstract: The invention provides a control apparatus for an induction motor to maintain torque following controllability even with use of inexpensive speed detection units having detection delay. In a control unit, a phase correction arithmetic circuit uses a motor speed detection value detected by a speed sensor and a low-pass filter and a detection delay time of a control system to compute a correction phase. An adder adds the correction phase to a magnetic flux phase obtained by a vector control computation. The addition corrects a magnetic flux phase deviation due to detection delay of the correction phase of a primary current command, and compensates for the detection delay so as to maintain the torque following controllability of an inductor motor.

Abstract: A driving control apparatus consists of a battery for storing electric energy supplied to a motor-driven compressor and a drive motor, a direct current detector for detecting a direct current supplied from the battery to the compressor, a direct current voltage detector for detecting a d.c. voltage applied by the battery, a controller for calculating an electric power consumed by the motor-driven compressor, determining an upper limit of the electric power in dependence on the d.c. voltage, judging whether or not the electric power is larger than the upper limit, and controlling the compressor to reduce the electric power in cases where the electric power is larger than the upper limit. Because the upper limit of the electric power is determined in dependence on the d.c. voltage and because the electric power becomes necessarily lower than the upper limit, an electric tar is not stalled by the exhaustion of the electric power in the battery before a driver arrives at his destination.

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: The invention relates to a procedure and an apparatus for adjusting the speed of an induction machine (1) fed by a frequency converter or an inverter (2) to a value corresponding to a reference value (f.sub.R). In the procedure, a frequency signal (n.sub.m) depending on the actual speed of the motor is generated and the reference value (f.sub.R) Of the motor speed is corrected by means of a correction signal (C) proportional to the slip of the motor. The corrected reference value is used as a frequency reference (f.sub.S) for the frequency converter or inverter. According to the invention, the correction signal (C) proportional to the slip is generated with the aid of the frequency signal (n.sub.m) depending on the actual motor speed and another frequency signal (n.sub.s ') formed from the frequency reference (f.sub.s) of the inverter. When the motor speed changes, e.g. due to variation in the load, the reference frequency of the inverter is corrected correspondingly.

Abstract: A capstan motor is controlled by a signal derived from a frequency generator that has been converted to a voltage that reflects the instantaneous change in velocity of the rotating motor. Acceleration of the motor is found by using a mean velocity obtained as a reciprocal of the pulsed signal from the frequency generator and then estimating the instantaneous velocity based on the derived acceleration. The estimated instantaneous velocity is converted to a drive voltage for the capstan motor so that the motor can be started and stopped with a respective constant acceleration and deceleration.

Abstract: A method and/or apparatus used with a motor controller for finding RMS current and RMS terminal voltage in a three phase AC induction motor using electrical values known to the controller. An equation relates average current to RMS current as a function of the duration of a known non-conducting period. Another equation relates known voltages to RMS terminal voltage as a function of a known phase angle and the known duration of the non-conducting period in a supply line.

Abstract: A slip frequency control method for induction motors, capable of achieving accurate control and excellent in control response.To effect determination of a slip frequency (fs) and an excitation magnetic flux frequency (.omega.0) by software processing to reduce a control error and a control delay caused if hardware elements are employed for the determination of these parameters, a vector control processor divides, in a speed control routine (101-104), the sum of a slip frequency, obtained by dividing the product of a secondary current command (I2) and a proportional constant (K2) by an excitation magnetic flux command (.PHI.), and a remainder (.alpha.') in the preceding routine by a routine executing frequency (CV), so as to derive a slip amount (A) and a remainder (.alpha.) in the present routine. In a current control routine (201 to 205) executed at intervals of a period shorter than that of the speed control routine, the processor divides the sum of the derived slip amount and the remainder (.beta.

Abstract: An electric motor control system compensates torque ripples to control the rotation of an electric motor more accurately. Compensated current amplitudes corresponding to the torques, speeds and rotational positions in the electric motor are stored in a memory 61. Address setting unit 91 prepares a read address AD.sub.1 in the memory 61 from the torque command T, speed information VL and rotational motor position P. The prepared read address AD.sub.1 is then used to read a torque error compensation data MD.sub.1 from the memory 61. An adder 12 adds the torque error compensation data MD.sub.1 thus prepared to the torque command T to determine current amplitudes AM in the electric motor. Three-phase current setting unit 10 sets three-phase AC current commands CU, CV and CW based on the current amplitudes AM and rotational motor position P. Thus, the rotation of the electric motor can be accurately controlled.

Abstract: An ac motor controller is operated by a modified time-switching scheme where the switches of the inverter are "on" for electrical-phase-and-rotation intervals of 180.degree. as opposed to the conventional 120.degree.. The motor is provided with three-phase drive windings, a power inverter for power supplied from a dc power source consisting of six switches, and a motor controller which controls the current controlled switches in voltage-fed mode. During full power, each switch is gated continuously for three successive intervals of 60.degree. and modulated for only one of said intervals. Thus, during each 60.degree. interval, the two switches with like signs are "on" continuously and the switch with the opposite sign is modulated.

Abstract: An apparatus and method for controlling driving of a apparatus such as a motor. A signal representing the position and/or velocity of the motor is received by a drive control unit. A microprocessor in the drive control unit provides a division ratio signal and a rotation judging signal to a clock pulse divider and two-phase pulse generator, respectively, and also calculates the velocity of the apparatus in accordance with the condition data. The clock pulse divider divides a clock pulse signal in accordance with the division ratio signal and outputs a divided clock pulse signal. The two-phase pulse generator generates two-phase pulses having a 90-degree phase shift of a given polarity with respect to one another in accordance with the divided pulse signal, and reverses the polarity of the phase shift in accordance with the rotation judging signal. The microprocessor further outputs a control signal to control driving of the apparatus in accordance with the calculated velocity and the two-phase pulses.

Abstract: An apparatus and method controls the speed of an AC induction motor by varying the frequency and current to the motor from an inverter power supply. A Counter EMF regulator receives a reference signal corresponding to the desired speed, and a signal proportional to CEMF for feedback. The output of the CEMF regulator is provided to the power supply to control the current to the motor. The CEMF feedback signal is also utilized to vary the output frequency of the power supply in accordance with the magnitude of the CEMF. This maintains the magnetizing component of stator winding current at a constant value for all operating frequencies of the motor. A signal corresponding to the load current component of the stator winding adds to the speed reference signal to the CEMF regulator to increase CEMF and frequency with increasing load, thereby to compensate for increased slip and maintain constant speed. The phase displacement between CEMF and stator winding current is determined.

Abstract: A position controller for controlling an electric motor comprises first position control circuit which provides first speed signal, second position control circuit which controls a mechanical system simulating circuit and provides second speed signal, an adder which adds the first and second speed signals to provide third speed control signal, first speed control circuit which receives the third speed signal and provides first torque signal, second speed control circuit which provides second torque signal, third speed control circuit which provides third torque signal, and an adder which adds the first, second and third torque signals to provide final torque signal. The output torque of the electric motor is controlled so that the output torque coincides with a torque represented by the final torque signal.

Abstract: A method for starting and operating an electric motor such as the spindle motor of a disk drive assembly employs a segmented stator winding. On startup, the winding segments are connected in series in order to maximize torque. Motor speed is detected, and when a predetermined speed is reached, the segments are connected in parallel to reduce the effective number of winding turns and maintain a control voltage for motor speed control. Switching of the winding segments can be by active elements such as FETs or by passive reactive elements responding directly to motor speed. For more gradual motor torque constant control, the winding may have more than two segments.

Abstract: An electric circuit provided with an abnormal condition detector for a motor, for use in a toner image forming apparatus, includes a current detection circuit for detecting a presence of a current when a power supply circuit is switched OFF; a test circuit for confirming a line connection between a control circuit and a switch by transmitting a test signal between the control circuit and the switch and a control circuit for determining an abnormal section causing an abnormal condition of a motor.

Abstract: A peak level of a drive signal U having predetermined inclination portions is detected, and a detection signal Q is outputted when the peak level has not reached a predetermined value. Since the detection signal Q indicates the out-of-step condition of the motor, the use of the detection signal Q allows reactivation or the like to be triggered easily in a simple circuit. Therefore, the rotation of the motor can be activated by reactivation or the like without strict adjustment but with only a practically adequate adjustment.

Abstract: In case an induction motor is controlled by a voltage type PWM inverter, reduction of an electromagnetic noise is made without enlarging a device.By providing an integrator 8 for obtaining an inverter phase angle by integrating an inverter frequency command and a carrier frequency modulator 9 for modulating so as to raise a frequency of a modulation signal for only a certain angle in the center of every 60 degrees of the phase angle, a magnetic flux vector can be brought closer to a locus of a circle so as to reduce the electromagnetic noise more than that of a conventional one.

Abstract: A brushless DC motor driving apparatus for a brushless DC motor which includes a rotor possessing a plurality of magnetic poles, a stator, and a stator winding with plural phases provided on the stator at a specific gap with respect to the rotor, the apparatus including: a sensor for generating sensor signals of plural phases showing a state of rotation of the rotor depending on the rotation of the rotor; a direction detector for detecting a rotating direction of the rotor from the sensor signals of plural phases and for outputting a direction signal; an initial phase detector for outputting a first phase signal depending on the direction signal and for producing an initial count value corresponding to a position of the rotor; a counter for setting an initial value corresponding to the initial count value, and for increasing or decreasing the count value depending on the direction signal and at least one of the sensor signals and for outputting a second phase signal; a waveform generator for generating a posi

Abstract: A rotation speed detecting apparatus for a motor includes a motor; an encoder section, attached to the motor, for producing at least two encoder pulse signals each 90 degrees out of phase from the other; a control and division number setting section for controlling the rotation direction and speed of the motor according to the loaded program, setting a division number and producing a division control signal according to the set division number; a quadrupled pulse signal producing section for producing an up/down pulse signal according to the forward and reverse rotation directions of the motor on a quadrupled pulse signal and an up/down pulse signal produced according to the state transitions in the encoder pulse signals; and, a frequency dividing section for counting up or down the quadrupled pulse signal and dividing the quadrupled pulse signal by the set division number.

Abstract: An apparatus for controlling a stepping motor (11) used for driving a chemical pump includes a random access memory (16) for storing a minimum current value required for driving the chemical pump at each of divisional intervals of one cycle of the chemical pump, two photo interrupters (13, 14) for sensing an angular location of the stepping motor (11) corresponding to each of the intervals of the chemical pump, and a central processing unit (17) connected to the two photo interrupters (13, 14) for controlling the stepping motor (11) in accordance with the angular location of the stepping motor (11) sensed by the two photo interrupters (13, 14), the central processing unit (17) being so arranged that it uses the minimum current value required for driving the chemical pump at an angular location following the angular location sensed by the two photo interrupters (13, 14).

Abstract: A motor rotation controlling device, usable for example in a video recorder, to minimize transient phenomena at an initial operation and shorten a transient response time for detecting a rotation speed of a motor, a signal processor for constantly controlling rotation speed of the motor by the detected rotation speed supplied from the rotation detector, a comb-shaped filter for removing a rotation period component and its harmonic component included in a control signal supplied from the signal processor, a controller for varying a transfer function of the comb-shaped filter at a transient response time and a normal time according to the rotation speed of the motor, a driving device for driving a motor by the filtered control signal supplied from the comb-shaped filter, and a limit device connected between the signal processing means and the comb-shaped filter for clamping the control signal.

Abstract: In a drive using an AC induction motor for moving a load in hoisting and lowering directions, a method for determining motor speed includes, in any order, the steps of selecting first and second voltage signals representing a maximum speed to be attained by the motor at rated output torque in the hoisting and lowering directions, respectively, and selecting a bias voltage. One of the voltage signals is combined with the bias voltage to obtain a feedback signal representing motor speed and the feedback signal is compared with a speed command signal to obtain a deviation signal representing the difference between actual and commanded motor speed. The drive is disabled if the difference is "out of" a predetermined range.

Abstract: A circuit and method for generating drive signals having a frequency synchronized to a reference frequency signal is disclosed. The circuit includes a PLL that includes a motor, and a circuit for generating a signal having a frequency proportional to the speed of the motor. A phase detector produces a signal for a time proportional to a phase difference between the motor speed signal and a reference frequency signal. A first phase difference measuring circuit produces a first voltage output signal at a first gain proportional to the phase difference when the duration of the phase detector signal is less than a predetermined time. A second phase difference measuring circuit produces a second output signal at a second gain when the duration of the phase detector signal is greater than the predetermined time. The first and second output signals are summed and applied to control the speed of the motor.

Abstract: A procedure for producing a speed reference signal for a crane motor control when the converter feeding the motor is controlled by means of at least one manually operated controller. To allow the speed reference signal to be changed, the controller has a control position in which the value of the speed reference signal is changed as a function of time. In order to facilitate more accurate manual control of the motor speed, when the speed of the motor is above a predetermined minimum value, the time derivative of the speed reference signal is changed during acceleration of the motor.

Abstract: A procedure is disclosed for filtering the speed feedback signal in an elevator motor drive which is provided with a speed controller and in which the speed of rotation of the motor is measured. The procedure of the invention involves sampling the speed feedback signal, producing a prediction of the next sample by a predicting procedure that filters the noise in the speed feedback signal, and forming an estimate of the latest sample by delaying the prediction by a time corresponding to one sample.

Abstract: An apparatus and a method for loading a cassette tape in a video equipment, in which driving of a DC motor can be controlled according to an amount of load which is applied to the DC motor when the cassette tape is loaded.

Abstract: An apparatus for preventing torque variation in a digitally controlled servomotor. Electrical angles .theta..sub.1 and .theta..sub.2 of the exciting magnetic field or the armature coil at respective timings of detecting and controlling a load current are obtained. The current is dq-transformed with .theta..sub.1 and inverse-dq-transformed with .theta..sub.2. As a result, even if there is a displacement of the actual electrical angle owing to the rotation of the armature during computing, it is possible to execute accurate current control. Further, at the time of calibration of the control system, the load currents are detected to be dq-transformed. From the d-axis components and q-axis components, values related to the offset and the amplification factor of the current detection systems are calculated. During the actual operation of the servomotor, the detected current value is corrected using the values. Further, the detection of the load current is performed plural times in one control cycle.

Abstract: A protection control circuit for a variable speed hoisting device driven by an induction motor includes, in addition to the inverter unit 1 for supplying power to the induction motor 2 and relays, a rotary encoder 16 and an abnormality detector 15. When the rotary encoder 16 does not generate output in spite of the fact that an operation instruction is input, the abnormality detector 15 opens the normally closed contact 15b2 to stop the inverter unit 1 and turns on the invertor abnormality display lamp 15d1 and rotation detector abnormality display lamp 15d2.

Abstract: The invention relates to a process for compensating a phase and amplitude response between a multiphase setpoint and actual value (i.sub.Rw, i.sub.Sw, i.sub.Tw and i.sub.Rx, i.sub.Sx, i.sub.Tx), the first step being to determine the modulus setpoint value (.vertline.i.sub.w .vertline.) or modulus actual value (.vertline.i.sub.x .vertline.) and the angular setpoint value (.epsilon..sub.w) or angular actual value (.epsilon..sub.x) of the setpoint or actual value vector (i.sup.w or i.sup.x), a modulus manipulative variable (.vertline.i.sub.wxy .vertline.) and an angular manipulative variable (.epsilon..sub.wxy) then being generated by modulus and phase from a modulus deviation (.vertline.i.sub.w .vertline.-.vertline.i.sub.x .vertline.) and an angular deviation (.epsilon..sub.w -.epsilon..sub.x) which are added by modulus and phase to the output quantities (.vertline.i.sub.w .vertline., .epsilon..sub.w) of the setpoint value vector computer (26), these modulus and phase sums (.vertline.i.sub.Kw .vertline.,.

Abstract: A power factor control system for an A.C. induction motor determines the difference in phase between the voltage applied to the motor and the current drawn by the motor. Based upon this difference in phase, an integrator generates an error signal. The error signal is compared with a ramp wave to derive a pulse signal which controls the voltage applied to the motor, which in turn controls the amount of current supplied to the motor, in order to reduce the power consumed by the motor. The integrator includes a dual-path feedback filter having a polarized capacitor in each path. A power supply is used to quickly provide the full operating bias voltages required by several of the components contained in the control system.

Abstract: A servo system for a motor having a rotor that includes a phase detector circuit for detecting a rotational phase of the rotor and for defining a plurality of angular positions of the rotor, each angle between adjacent angular positions being of the same size, a rotating device for rotating the rotor at a predetermined constant rotational speed, a speed detector circuit for detecting a rotational speed of the rotor at each of the angular positions, an error detector circuit for detecting errors of the speed detector circuit at each of the angular positions when the rotor is rotated at the predetermined constant rotational speed, a memory for storing the detection errors at each of the angular positions, and a servo control circuit for controlling a rotational speed and/or phase of the rotor in accordance with the rotational speed detected by the speed detector circuit and the detection errors read from the memory.

Abstract: A non-invasive system for accurately determining the counter EMF or speed voltages in an electric motor during motor operation. The system includes a mechanism for determining the phase angle of the stator current within the dq frame of reference and a mechanism for transforming feedback voltages into a new frame of reference defined by this phase angle. The speed voltage values thereby detected are free from stator resistance effects and represent parameters of improved accuracy which can be used in motor control functions.

Abstract: A propulsion system for using a pair of electric induction motors to power a pair of vehicle drive wheels. The motors are driven by pulses of electric current from a common dc bus. The inductance of stator windings cause electric current to power the motors during the time between pulses so power from the dc bus is low. When a vehicle is making a tight turn, an inside motor provides an electric current to the dc bus to supply additional power to an outside motor. Speed and steering signals operate the electric motors and control speed of an engine and an alternator which supply power to the dc bus.

Abstract: A circuit for controlling the velocity of the spindle motor in an electronic device using a disk is disclosed. Particularly, an abnormal rotation preventing circuit is disclosed which monitors the angular velocity of the spindle motor and forcibly controlls it to rotate within a predetermined velocity range when it deviates from the predetermined range. The duty value of a phase difference between two signals among first, second and third phase control signals for driving a three-phase motor is measured. Then, the phase difference is counted and the velocity is sampled. An abnormal rotation control signal is generated when the sampled velocity deviates from the predetermined range. The motor's velocity is then forcibly controlled so as not to deviate from the predetermined range, thereby preventing abnormal rotation of the motor.

Abstract: A driving system for an induction motor which is capable of properly controlling the speed of an induction motor over its high-speed revolution range and also features an excellent responsiveness to a speed command. In this system, a slip pulse (SSP) and a phase shifting pulse (FSP) are calculated by a slip pulse generator circuit (20) and a phase shifting pulse generator circuit (21) in accordance with slip pulse data (SB) and phase shifting pulse data (FB) which are calculated by a processor (1) in accordance with the speed command and an output of a speed detector. A counter (24) issues the first changeover signal (CS1) each time it receives a specified number of pulses from a pulse overlapping circuit (23). The first changeover signal corresponds to a feedback pulse calculated in accordance with the output of the speed detector and also to the slip pulse and the phase shifting pulse added.

Abstract: The invention relates to a spindle speed/position control system for use in a numerically controlled machine tool such as a lathe. To improve the measurement of spindle speed and position, detected elements are attached directly to the rotatable spindle. A waveform shaping circuit takes the outputs of speed and position detecting sensors, and outputs a variety of sinusoidal and pulse signals. The sinusoidally varying signals are employed in speed detection while the pulse signals are used for position detection and control.

Abstract: A speed control method and apparatus for a motor driven by output of a power conversion unit, wherein a first current command value is inputted to derive a drooping variable, a deviation between a detected speed value of the motor and a speed command value is derived, the first current command value is derived on the basis of a value obtained by compensating the deviation with the drooping variable, the speed command value is inputted to derive an acceleration or deceleration current value for accelerating or decelerating the motor, and the first current command value and the acceleration or deceleration current value are added together to derive a second current command value and control the output current of the power conversion unit on the basis of the second current command value.

Abstract: A control circuit for connection to a split capacitor motor automatically switches to reverse operation when the motor is caused to stop or slow unacceptably by a heavy load. During operation, a voltage is maintained across a relay winding which is sufficient to hold the relay contacts in the normally open position. A slowing or stopping of the motor causes a reduction the voltage across the relay winding, which permits the relay contacts to switch to a configuration that reverses the phase of the current through the main and auxiliary windings of the motor, thereby reversing the motor.

Abstract: A printing cam is rotated forward from a print starting position by a motor in a printing operation. Then, a print hammer is driven in association with a cam follower driven by the printing cam, so that a printing operation is executed. An encoder disk is disposed so as to rotate integrally with the printing cam. A plurality of slits are disposed in an equidistantly spaced relationship in an encoder disk. A phase setting portion is provided in the encoder disk as a reference position for providing a rotational position of the encoder disk. The phase setting portion is an interval between two specific slits, the interval being formed by enlarging the interval between two slits. While the encoder disk rotates forward, a slit counter executes an additional operation every time a photosensor detects a slit. While the encoder disk rotates reversely, a slit counter executes an subtractional operation every time the photosensor detects a slit. After the printing operation is ended, the motor rotates reversely.