Abstract: A speed sensor for an electric motor detects the variation in the electric field of the armature due to commutation to produce an output signal indicative of the speed of rotation of the motor.

Abstract: An electronically switched motor includes a stator-rotor assembly fitted with three-phase driving windings, a series of switches for powering the windings, and a control circuit suitable for regulating a speed of the motor as a function of a reference speed and a measured speed. The control circuit includes switch control elements to cause each switch to switch on and off in compliance with a repeated sequence selected to power the driving windings as a function of the reference speed and the measured speed. The sequence includes a succession of on/off pulses with a duty ratio. The control circuit is suitable for generating a first switch control mode for controlling the switches so that the switches are in an ON state or receive a succession of ON pulses over a first activation period and a second switch control mode for controlling the switches so that the switches are in an ON state or receive a succession of ON pulses over a second activation period larger than the first activation period.

Abstract: A DC motor control apparatus includes Hall effect devices each generating a pulse each time a DC motor rotates a predetermined angle. When a control circuit judges, based on the pulse signals generated by the Hall effect devices, that the rotation rate of the motor has decreased below a predetermined rate, with a command to stop the motor given, the control circuit generates a servo command signal. When the servo command signal is generated, the control signal also generates, based on the pulse signals, a rotation direction indicating signal to indicate that the motor should be driven to rotate in the opposite direction. After generating the servo command signal, the control circuit generates and holds a braking force indicating signal indicating the braking force in accordance with the actual rotation rate of the motor. A driver drives the motor in the direction indicated by the rotation direction indicating signal with a braking force indicated by the braking force indicating signal.

Abstract: A method and apparatus for controlling the output function of a permanent magnet brushless DC motor (20), by sensing an input current to the motor (20), by computing an output torque generated by the motor (20) as a function of the input current to the motor (20), by computing an output pressure for a pump (22) in response to the output torque, by reading a set point pressure, and by comparing the set point pressure to the output pressure, and in response thereto controlling on-off operation of the motor (20). The apparatus includes a sensing circuit (28) and a microelectronic processor (30) for performing these functions.

Abstract: Disclosed is an apparatus and a method for controlling a rotation speed of a motor. The apparatus includes a detector electrically connected to said motor for generating a first detection signal corresponding to a feedback signal output from said motor; and a controller electrically connected to said motor and said detector for receiving said first detection signal. When said motor rotates at a relatively low rotation speed, said controller generates a first control signal with a first frequency to be output to said motor corresponding to said first detection signal; when said motor rotates at a relatively high rotation speed, said controller generates a second control signal with a second frequency to be output to said motor; wherein said first frequency of said first control signal is greater than said second frequency of said second control signal.

Abstract: A motor controller for regulating the speed and limiting the input current to a dc motor is disclosed. The motor controller includes an electronic control unit, a current sensor and a speed sensor. The motor controller provides control of the dc motor by applying a varying voltage to maintain a motor speed in the presence of a varying load. The motor controller also monitors the input current to the dc motor to predict an input current to the dc motor. The ECU compares the predicted input current to a input current limit range and switches to a current-limiting mode when it determines that an overcurrent condition is reached based on the comparison. The motor controller modifies the control signal by a first control decay factor when the predicted input current exceeds the input current limit range. The motor controller modifies the control signal by a second control decay factor when the predicted input current is within the input current limit range level.

Abstract: Practically ideal electrical resonance is employed to soley provide armature power, and stator power if desired, to run DC motors. A practically ideal parallel resonant tank circuit (PIPRC) is used wherein the quotient of the “tank current” divided by the “line current” (called the “quality” or “Q” of the tank) is (1) greater than one, (2) large enough to allow the percent efficiency of the electric motor to be equal to or greater than 95%, and (3) removes enough back emf or enough of the influence thereof so that criteria (1) and (2) can be realized throughout the entire operating range of the motor. Only one PIPRC is needed for a DC motor. Recontrolling and/or redesigning is done for two reasons.

Abstract: A process and a circuit (2) for regulating the speed of an electric motor (1) having a high speed (N1) to at least one additional lower speed (N2, N3, N4), whereby, in a first prioritized step, depending on a preselected speed (N1, N2), the regulation of the speed to a lower effective motor voltage (Ueff) has an upper limit, and in a second step, depending on the torque (M) needed for the regulation to this preselected speed (N1, N2), the effective motor voltage (Ueff) is regulated within the limited range.

Abstract: A method and apparatus for controlling power supplied to a motor comprising a power controller having a source of electrical power for providing the necessary power to operate the apparatus, an oscillator for generating gating signals at a relatively higher frequency than the electrical power supplied, circuitry responsive to the gating signals for gating the low frequency electrical power to generate a DC voltage, and an inhibitor for inhibiting the generating of gating signals by the oscillator to regulate the DC voltage generated so as to control the speed of any motor connected to the apparatus. The apparatus may be setup to inhibit the oscillator when certain circuit conditions such as an over current condition is detected. The apparatus may also be setup to keep the oscillator in an OFF state once inhibited until a specified amplitude or period of the input signal has been reached.

Abstract: A regenerative converter for a DC motor (55) having an armature (A, B) and a field (57), comprises a conventional three-phase matrix converter (6) including a three-phase bridge (7), the output of two phases being connected (52, 53) across the armature of the motor, the third phase being connected (58) to one end (K) of the DC motor field (57). The other end (I) of the DC motor field (57) is connected (59a) through a plurality of diodes (61, 62) to respective phases of the input power.

Abstract: A flat pack blower utilizes surface mounting techniques for mounting the blower electronics on a thin laminated circuit board to reduce the blower profile. To that end, the blower includes a stator, and a rotor rotatably coupled to the stator. The stator includes a coil, a pole coupled with the coil, and a laminated circuit board having blower control circuitry and pads for electrically connecting the blower control circuitry to the coil. Use of surface mounting techniques on the laminated circuit board thus eliminates the discrete electronic components and the wires connecting such components.

Abstract: A power supply for DC motors, in particular for actuators for use in the adjustment of tables, beds and the like, comprises a transformer (T1) with a rectifier (D1-D4); and a buffer capacitor. The power supply comprises voltage limiting unit (Z1) coupled in parallel with the motor and connected to switch unit (Q1) so that the motor is connected on a first part of the sine half-waves, but is disconnected when the voltage determined for the voltage limiter is reached. This ensures a good mean voltage, and the voltage does not exceed an upper permissible value. This also means that the motor speed is more independent of the load, which is an advantage e.g. in case of height-adjustable tables. In an embodiment, the power supply comprises additional means for measuring the current power in the motor, and this measurement is used as a feedback for controlling the motor speed to keep the speed of the motor.

Abstract: A monitoring system monitors a microcomputer in which an angle calculator calculates the electrical angle of a motor using output signals from a rotation angle sensor. In the microcomputer, a control signal generator generates a coded control signal that indicates the range to which the calculated electrical angle belongs. In the monitoring system, the electrical angle detected by the rotation angle sensor is multiplied by an excitation signal provided for the rotation angle sensor, and an angle detector detects the resultant signals. Based on the detected signals, a supervisory signal generator outputs a coded supervisory signal that indicates the range to which the electrical angle detected by the rotation angle sensor belongs. Then a fault detector determines that a failure occurs in the microcomputer, if a comparator determines that the coded control signal disagrees with the coded supervisory signal.

Abstract: In controlling a motor in a device which drives a mechanism using the motor as a power source, in executing driving, an ideal profile of the driving is generated in accordance with a target position and a preset initial parameter, driving of the motor is controlled in accordance with the profile, the value of the initial parameter is evaluated at the end of driving, and the value of the initial parameter is changed in accordance with the evaluation result. High-speed accurate position control can be achieved independently of the characteristic of an individual motor to be used.

Abstract: In controlling a motor in a device which drives a mechanism using the motor as a power source, pre-driving of giving a predetermined driving parameter to the motor and driving the mechanism is executed. During the pre-driving, movement of the mechanism is monitored, and a command value to the motor, which is necessary for starting the mechanism, is obtained. Driving of the motor is controlled using feedback using the command value as the initial value of the driving parameter. High-speed accurate position control can be achieved independently of the individual difference in an object to be controlled and the frictional force of the mechanical portion or the difference in use environment.

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

Abstract: A method to operate an electronically commutated DC motor driving a centrifugal pump and comprising a stator fitted with at least one winding and a rotor fitted with permanent magnets, said method including a monitored stepping operation within which one full revolution of the rotor is constituted by a sequence of distinct individual steps, the rotor being accelerated by applying a stator field and being decelerated to a stop before the stator field is commutated.

Abstract: An adaptive motion controller for driving a servo motor. The adaptive motion controller has an amplifier including a voltage command which can be set at a voltage at which the amplifier will be operated, a frequency selector which can be set at a frequency at which the amplifier will be operated, a power supply having a current feedback, and a control for driving the servo motor in a test mode wherein the voltage command is set at a selected voltage, and the frequency selector is sequentially set with a series of different frequencies. The servo motor is operated at each frequency, and the frequency of the series of frequencies that has the lowest current feedback is determined and the frequency selector is set at that frequency when the amplifier is operated to drive the servo motor.

Abstract: A tan having a fan wheel and an electric motor driving it, and a control unit for controlling the motor output as a function of fan-specific parameters. An actual-value signal corresponding to an actual rotational speed of the fan is measured and compared with a control signal corresponding to a required speed, and the actual speed is adjusted to the required speed by means of the control unit, wherefore the actual speed and the actual motor current or supply current are measured and conducted to a microcontroller as input signal variables, whereby the fan-specific data such as wheel diameter, density of the conveying medium, fan coefficients, motor coefficients, and a preset artificial characteristic curve ps=ƒ({dot over (V)}s ) are stored in the microcontroller as default values.

Abstract: A pulse generating circuit for motor rotation of a direct current motor which is capable of pulse generation following the variation of the motor rotation condition and of stable ripple pulse generation. The pulse generating circuit for motor rotation includes a filter for varying a cut-off frequency fc by the signal from outside and for removing the noise based on the input signal from the direct current motor, a pulse forming circuit for forming the ripple pulse in accordance with the motor rotation of the direct current motor based on the output from the filter, a clock generating circuit for varying the cut-off frequency fc of the filter by providing the clock signal fCLK which is generated based on the rotational condition signal of the ripple pulse and the direct current motor to the filter, and a pulse correction circuit for generating the corrected ripple pulse when the frequency ratio between the ripple pulse and the clock signal fCLK is deviated.

Abstract: In a circuit arrangement for starting a DC motor comprising at least one field winding, particularly for switching on a DC motor for driving a hydraulic fluid pump for operating hydraulic actuators of a vehicle loading platform system, means are provided for switching on at least one field winding and means activatable by the switching on of the at least one field winding for fully activating and starting the DC motor.

Abstract: A constant speed control circuit for a fan includes a timing control circuit, a signal comparing circuit connected to the timing control circuit, a driving circuit connected to the timing control circuit, and a signal generating circuit. The signal comparing circuit receives an external frequency signal from a frequency generator and a timing signal from the timing control circuit. By comparing the external frequency signal and the timing signal, the signal comparing circuit outputs an correction output signal to the timing control circuit for driving coils of the fan through the driving circuit. The external frequency signal represents an expected rotational speed of the fan, and thus by providing a fixed frequency value, the fan is operated in a constant speed status.

Abstract: A motor controller utilizes sensors to detect the rotational speed and relative position of the motor rotor and generates a voltage vector to maintain the motor current in phase with the EMF before a voltage limit is reached. The approximate actual speed is calculated and position signals are generated by the calculator. The actual speed is compared with a command speed signal and any difference gives rise to an error signal. A proportional integrator receives the error signal and produces a correction signal for a vector rotator corresponding to the desired vertical voltage component necessary to achieve the command speed. After the voltage limit is reached, any further speed increase desired is achieved by rotation of the voltage vector with it's amplitude unchanged.

Abstract: A disturbance compensation control system which restricts periodic disturbance of a control object such as a motor includes a repetition control unit. The repetition control unit restricts the periodic disturbance to the control object. The repetition control unit is designed so as not to perform a repetition compensation control when the control object is initially started.

Abstract: A sensorless brushless-DC-motor mounted on an electric or hybrid vehicle is powered by an on-board battery through an inverter supplying a three-phase pulse width modulated voltage (PWM voltage). The inverter is controlled to generate the PWM voltage having an average voltage level corresponding to a target motor speed. The PWM voltage level is controlled by changing its duty ratio, so that a difference between the target motor speed and an actual motor speed is minimized. The actual motor speed is determined based on a signal indicating a rotor position detected from the PWM voltage imposed on the motor. When the battery voltage drops and the duty ratio becomes 100%, the target motor speed is temporarily reduced to the level of the actual motor speed. When the battery voltage is recovered and the duty ratio becomes lower than 100%, the target motor speed is gradually increased again to the original level.

Abstract: A motor control apparatus and a method according to the invention are directed to detecting a motor velocity. Leading and trailing edges of two pulse signals are distinctively detected from one another, and those pulse signals have cycles which are proportional to the motor velocity, and a phase difference between the pulse signals is about one quarter of a single cycle from one another. Then, a period of time between the pulse edges in the same direction of the same pulse signal is measured, and the period of time between the pulse edges is used to sequentially convert it into the motor velocity and thereby detect the motor velocity.

Abstract: A device for position determination in a sensorless direct current motor has a plurality of inductivities arranged in corresponding phases and inducing alternating voltages in a motor windings, a plurality of resistances located in phase branches to be evaluated for a position determination of a rotor position of the sensorless direct current motor, and a plurality of comparitor components each associated with the corresponding phase branch to be evaluated.

Abstract: Shunt automatically controlled output circuit incorporating stored voltage or counter EMF loading, featuring serial incorporation of an isolation diode way between a D.C. power supply and battery in which a voltage is stored or a D.C. motor bearing an armatured counter EMF, such that once a loading which functions to store voltage as well such as a load in the form of a secondary cell or capacitor or super-capacitance capacitor or of a D.C. motor bearing a counter EMF by reason of its terminal voltage exceeds a predetermined threshold, the resistor that is shunted in parallel across the power supply will be made conductive by the load voltage testing circuit, whereby voltage on the power supply side is reduced, and that bringing about a cut in the voltage differential with respect to the loading terminal, so that power that is being delivered to the load is reduced in the long run.

Abstract: A circuit for the speed recovery of a direct current motor comprises an output stage, that includes a first couple of transistors and a second couple of transistors, and first means, for detecting a current circulating in said motor. The circuit has the characteristic of comprising second means, suitable for activating said second couple of transistors of said output stage for a determined first time period so as to short-circuit said motor, and at the end of said first time period said second means being suitable for unbalancing said output stage so as to force the maximum current circulating for a determined second time period in function of the value detected by said first means during said first time period so as to stop said motor.

Abstract: The invention relates to an electric drive device with a DC motor (2) comprising a control circuit with an electronic commutator (3). The invention is characterized in that a derivation of a control signal (V_i_ref) is obtained from an induced motor voltage (E_sample) detected by a measuring device and from a reference value (V_i_av) which serves to regulate the speed of the DC motor (2), and in that the derived control signal (V_i_ref) serves to achieve a substantially constant torque of the DC motor (2) through adjustment of the motor currents (ia, ib, ic).

Abstract: A direct current motor rotation detecting apparatus and a direct current motor rotation control apparatus detect and control at least one of a rotational direction, a rotational speed, a rotational position, and a cumulative rotation number of a rotor of a direct current motor. The apparatus include at least one rotation detecting brush which detects a rotation of the rotor, a differentiating circuit which differentiates a voltage obtained through the at least one rotation detecting brush, and a pulse generator triggered by the differentiating circuit at a time interval proportional to a rotational speed of the direct current motor to generate pulses having a predetermined pulse width.

Abstract: Disclosed is an improved three-phase direct-current (DC) brushless motor with Hall elements, in which two Hall elements instead of three Hall elements are placed upon the driving circuit of the DC brushless motor to sense the variation of the magnetic flux during the operation so as to reduce the manufacturing cost and also improve the operation precision.

Abstract: The system comprises a pressure sensor for providing a signal indicative of the pressure of the refrigerant fluid of the air-conditioning system at the output or delivery of the compressor of the system, a sensor for detecting the temperature of the liquid flowing through the engine-cooling system (R), an activation sensor for providing a signal when the air-conditioning system is activated, a sensor for detecting the speed of forward movement of the motor vehicle, and a control and operating unit connected to the sensors and to the electric motor and arranged for: determining a first speed for the electric motor in accordance with a function of the pressure of the refrigerant fluid of the air-conditioning system and of the speed of the vehicle, determining a second speed for the electric motor in accordance with a function of the temperature of the engine-coolant liquid and of the speed of forward movement of the vehicle, and sending to the electric motor control signals to bring its speed of rotation to

Abstract: An inverter-fed three-phase electrical motor (1) for a household appliance is grounded through a protective conductor (8), with the motor being particularly provided for the direct drive of washing machines. The motor includes a pick-up for high-frequency currents originating from an actuation of the inverter (7) and conducts the currents to one pole of a D.C. voltage supply (13) for the inverter (7) through an ohmic or capacitive shunt path (18-19), with the shunt path leading from a stator (3) of the motor which is installed electrically insulated into the household appliance and is not connected to the protective conductor (8).

Abstract: A system and method for controlling a brushless DC motor (58) is provided. The motor (58) includes a rotor (72) and a stator (96) having at least three phases. The rotor (72) is magnetically coupled to and moveable by the stator (96) when the coils (94) are appropriately energized. Each of the coils (94) is characterized by a corresponding voltage waveform. No more than two position sensors (122) are provided for sensing the position of the rotor (72) during a start-up mode. Each position sensor (122) has an associated position sensor signal. The position sensors (122) are aligned to sense the rotor position such that each position sensor signal indicates a zero torque point corresponding to a phase voltage waveform. The position of the rotor (72) is sensed such that the position sensor signals indicate the start-up operating state of the motor (58). During a first ambiguous start-up state, two predetermined coils (94) are alternately energized.

Abstract: A DC fan using a power supply and sleep/non-sleep-mode signals for controlling the rotating speed thereof includes a DC brushless motor and a power sleep-mode control unit. The DC brushless motor serves as a driving source of the DC fan. The power sleep-mode control unit is electrically connected to the DC brushless motor for receiving the power supply and the sleep/non-sleep-mode signals, thereby outputting an operating power supply and controlling the rotating speed of the DC brushless motor.

Abstract: A controller using rectified AC voltage to drive a DC motor. A first rectified produces a waveform that passes through zero voltage in synchronization with the A.C. supply voltage. The first rectified voltage is applied to the D.C. motor. A second rectified voltage produces a waveform that passes through zero voltage in synchronization with the A.C. supply voltage. A circuit generating a unipolar waveform output voltage drives a switch that turns on and off the connection of the first rectified voltage to the D.C. motor. The on time can vary from zero to one half of the period of the AC voltage for maximum speed. The switching is synchronized with the unipolar waveform. The time on is varied by varying the pulse width driving the switching device.

Abstract: A system and method for reducing the cost of producing a brushless DC motor (58) is presented. The brushless DC motor (58) provides higher power density and efficiency with an increased tool run time. The brushless DC motor (58) includes a rotor assembly (72) that has an unmagnetized permanent magnet (74) affixed to a shaft. The permanent magnet (74) remains unmagnetized until the motor is partially assembled. A plurality of coils (94) for producing a magnetic field are wound about the rotor assembly (72). The coils (94) include end turns that enclose the rotor assembly (72) such that the rotor assembly (72) is not removable. Since the windings (94) are wound with the rotor assembly (72) already enclosed, the windings (94) do not require large end coils to allow subsequent insertion of the rotor (72). Minimizing the end coils reduces the length of wire required per turn, thereby reducing the resistance of the winding (94).

Abstract: A direct current motor rotation control apparatus, a method and device for controlling a rotational speed of a direct current motor, and an apparatus having the direct current motor rotation control apparatus. The apparatus and device control rotational operations of a direct current motor such that the direct current motor rotation control apparatus includes at least one rotation detecting brush which detects a signal indicative of an operation of the direct current motor, a motor driving circuit which drives the direct current motor by applying the direct current drive voltage to the pair of electrode brushes, a reference voltage generating device which generates a reference voltage a comparator which compares a voltage detected by the rotation detecting brush with the reference voltage generated by the reference voltage generating device and produces an output comparison voltage, and a motor control circuit which adjusts the direct current drive voltage based on the output comparison voltage.

Abstract: A motor control unit (1) includes a white noise generator (8), an instruction switch (9) for switching between an input control instruction (Vins) and a white noise output of the white noise generator (8), a controller (10) for feedback controlling the motor drive velocity, a detection unit (13) for detecting and sampling the real velocity of a motor or a load at a predetermined period, a first Fourier transformer (15) for Fourier-transforming the control instruction data (Cins) together with the sampled velocity data (Vm), and a first frequency characteristic operation unit (16) for calculating the frequency characteristics in a range from the velocity instruction (Cins) to the sampled velocity (Vm) based on output data of the first Fourier transformer (15), thus obtaining the frequency characteristics in a short period without necessity of a servo-analyzer.

Abstract: A BEMF detector and method detect the BEMF of a three-phase motor using a fully differential detection system. The motor has a first coil coupled between a first coil tap and a center tap, a second coil coupled between a second coil tap and the center tap, and a third coil coupled between a third coil tap and the center tap. The BEMF detector includes a differential amplifier having first and second inputs and first and second outputs, with the first input being coupled to one of the coil taps and the second input being coupled to the center tap. The BEMF detector also includes a comparator having first and second inputs coupled respectively to the first and second outputs of the differential amplifier and an output at which a BEMF signal is produced that is related to the BEMF of the motor. The differential amplifier may be part of an anti-alias filter structured to fix to a known stable value a common mode at the outputs of the differential amplifier.

Abstract: A vacuum pump for use in an evacuating system for a semiconductor fabrication apparatus is operated at a steady rotational speed to evacuate the semiconductor fabrication apparatus. Then, in response to a signal indicative of an operating state of the semiconductor fabrication apparatus which does not need to be evacuated, the rotational speed of the vacuum pump is reduced to an idling rotational speed, thereby to lower electric energy consumption by the vacuum pump.

Abstract: A rotation control for a device to be rotated includes a variable speed DC motor having a constant rotational speed upon receiving a selected fixed voltage electrical input power from an adjustable electrical input power supply connected to the motor for supplying the selected fixed voltage. A switch circuit is connected between the motor and the power supply activatable in response to a first electrical signal to turn the motor "on" and activatable in response to a second electrical signal to turn the motor "off". A selectable frequency, regular interval electrical signal device is connected to the switch circuit to provide electrical signals to activate the switch circuit to turn the motor "on" at regular intervals. An encoder wheel is coupled to the device to be rotated and to the motor for rotation of the timing disk at a speed proportional to the constant rotational speed of the motor. The timing disk has a plurality of openings around the disk with predetermined spacing there between.

Abstract: A motor control circuit, including a filter amplifier which includes a clamping circuit to limit the maximum voltage of the filter amplifier. The filter amplifier is clamped to essentially the same level as the following error amplifier, which drives the power transistor which drives the motor. Thus, the requisite control voltage is normally present anyway (since this voltage is used to limit the amount of maximum current in the motor). Since the corresponding level of current is selected to ensure adequate current during start up, this signal is therefore appropriate to limit the output voltage of the filter amplifier. This improvement adds very little circuit complexity, and reduces the settling time of the motor controller at startup.

Abstract: A control method of a servomotor, such that a moving command for position-velocity processing, which is executed in every sampling period obtained by dividing a distribution period of moving commands into N units of equal parts, is determined from the above described moving commands of the distribution period. A velocity compensatory component is obtained on the basis of a moving command in a distribution period preceding by one period the present distribution period and is added to a velocity command, and an acceleration compensatory component obtained on the basis of a moving command preceding the time of the present position-velocity loop processing is added to a torque command, so that the phase of acceleration compensatory data is advanced from that of velocity compensatory data in feedforward operations.

Abstract: A brushless motor speed detector requires no FG pattern or FG magnetization so that a motor structure is not restricted. The detector includes a simple detection circuit and a simple detection signal processing circuit, and is capable of obtaining a high-accuracy detection signal by using a variable signal output circuit for providing a signal alternately varied due to the rotation of a motor, a constant signal output circuit for providing a signal not varied due to the rotation of the motor, and a comparator for comparing an output signal of the variable signal output means with output signals of the constant signal output means or for comparing output signals of the first and second variable signal output circuit with each other to provide speed detection signals for one turn of the motor more than the number of driving magnetized poles.

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: An AC motor is provided with a motor housing and a photoelectric sensor associated with the housing. The sensor is part of a motor control circuit which is thereby responsive to the ambient light condition to control the motor by selectively switching At on and off, or alternatively by selectively switching between higher and lower speeds. The control circuit derives its power from the motor's AC input terminals, thereby yielding a self-contained motor control unit, which requires no timer unit and no wiring or mounting by the user. In accordance with another aspect of the present invention, the photoelectric sensor extends through an aperture in a motor housing end cap with the associated control circuitry fitable within the end cap, thereby providing a retrofit for existing motors.

Abstract: A speed control apparatus for a motor has a driver for the motor. The motor's rotational speed is detected, and a signal from the detector is counted. Signals from the counter received as the input by another circuit, which outputs data representing irregularities in the detection signal once the motor has reached its constant speed. Correction information is supplied to the motor driver on the basis of the irregularity data.

Abstract: A method and system for sensing the rotor speed of a brushless permanent magnet motor wherein a signal containing isolated third harmonic components of the flux density is acquired, and the absolute values of the maximas of the signal are measured, the last measured absolute maxima representing the current rotor speed of the motor.