Abstract: A selectively configurable electric motor comprises a stator and a plurality of poles electrically coupled to the stator. The selectively configurable electric motor also includes an actuator separated from the poles by an air gap and configured to move relative to the stator in the presence of an electromagnetic field. The selectively configurable electric motor further includes a plurality of electric conductors, each of the plurality of electric conductors substantially wound around one of the plurality of poles. The selectively configurable electric motor also includes a power converter, at least a portion of which is coupled to the plurality of electric conductors, including a plurality of switching elements configured to selectively couple one or more of the plurality of electric conductors in a predetermined electrical configuration.

Abstract: An AC motor speed controller includes a plurality of capacitors that may be selectively switched, by means of controllably conductive switches, into series electrical connection with an AC motor and an AC voltage source to control the speed of the motor. To change the speed of the motor, a control circuit renders a first switch conductive, in response to a first detected AC voltage zero crossing, to charge a first capacitor to a predetermined voltage. The control circuit then renders a second switch conductive, in response to a subsequent second detected AC voltage zero crossing, to charge a second capacitor to the predetermined voltage. The control circuit then renders both switches simultaneously conductive at a predetermined time after a subsequent third detected AC voltage zero crossing. The capacitors will thereby be charged to the same voltage prior to being switched into series with the motor, thereby resulting in reduced acoustic noise when changing motor speeds.

Abstract: A washing machine and a method of operating same is disclosed. A electronically commutated motor for using in a washing machine is also disclosed. The washing machine has an agitator operated by an electronically commutated motor. An agitate cycle of the washing machine is detected. During an agitate cycle, the motor is electronically commutating with two phase firing if the agitator is rotating at rate below a first threshold, or the motor is electronically commutating using an optimised firing angle with three phase firing if the agitator is rotating at rate above a first threshold.

Abstract: The invention relates to a three-phase asynchronous electric motor for domestic appliances, comprising power elements, such as triacs or relays, for charge control. The power elements other than the relays are controlled by at least one microcontroller with the aid of an optical insulation means, ensuring electronic programming and also control of the motor with the aid of a command. The microcontroller or microcontrollers are references to a zero potential of a recovery and filter block feeding the motor. The controller can be applied to a washing machine in order to control the electric motor which rotationally drives the drum.

Abstract: Moderately accurate closed loop speed control of a universal motor is attained without the need for any type of speed sensor. Motor armature (across the brushes) voltage is sensed and supplied to a control circuit for processing along with sensed motor current and zero-crossing information. Integration of the motor armature voltage provides a value which is related to current motor speed. By adjusting the gating angle for triac actuation, the armature voltage integral can be maintained at a desired value associated with a desired motor speed. The sensed motor current is also integrated to provide a speed droop compensation value that is added to the desired value, and the gating angle for triac actuation is adjusted to move the armature voltage integral value to approach the summed value of the speed droop compensation value and desired value.

Abstract: An AC motor speed controller includes a plurality of capacitors that may be selectively switched, by means of controllably conductive switches, into series electrical connection with an AC motor and an AC voltage source to control the speed of the motor. To change the speed of the motor, a control circuit renders a first switch conductive, in response to a first detected AC voltage zero crossing, to charge a first capacitor to a predetermined voltage. The control circuit then renders a second switch conductive, in response to a subsequent second detected AC voltage zero crossing, to charge a second capacitor to the predetermined voltage. The control circuit then renders both switches simultaneously conductive at a predetermined time after a subsequent third detected AC voltage zero crossing. The capacitors will thereby be charged to the same voltage prior to being switched into series with the motor, thereby resulting in reduced acoustic noise when changing motor speeds.

Abstract: The invention relates to a method and a circuit for regulating the speed of a commutator series-wound motor, especially a universal motor (10), which is supplied with a current from an a.c. voltage source (22) by means of a semiconductor switching element (18) mounted in series with an armature winding (12) and a field winding (14, 16) and controlled by a control unit (28) according to a nominal speed value. The control unit (28) receives, as input signals, signals corresponding to the total voltage drop (Umot) when the motor (10) is supplied with a current, and a substitute signal for the intensity of the motor current (I), corresponding to the voltage drop (Ua, Ufa) on the armature (12) alone or on the armature (12) and on a part (14) of the field winding (14, 16).

Abstract: An apparatus for controlling the speed of an AC motor comprising a switch adapted to be coupled in parallel with power terminals for the AC motor; a capacitor coupled in series with the parallel combination of the switch and the motor; the capacitor adapted to provide an AC supply voltage from an AC source to the parallel circuit comprising the motor and the switch; and a control circuit for controlling the conduction time of the switch in order to vary the speed of the motor. The switch is preferably pulse-width modulated at a frequency twice the line frequency of the AC supply voltage, and the switch is turned on when the voltage across the AC motor is zero volts. The apparatus is operable to provide for continuously variable control of the motor speed while minimizing acoustic noise in the motor.

Abstract: A direct current motor controlling method includes a mean for transforming a duty signal to computed value by a microprocessor unit. The microprocessor unit computes the computed value and then produces a target value by executing a dichotomy method, a rotation method and a transformed function, capable of reducing executing time and executing load of the microprocessor unit and saving memory space. The microprocessor unit sends a frequency signal to a driving circuit unit according to the target value. The driving circuit unit receives the frequency signal and then provides a driving voltage to a power switch. The power switch provides a voltage to a direct current motor or not according to the driving voltage for controlling output performance of the direct current motor.

Abstract: A power tool is disclosed comprising a controller for controlling at least one operating parameter, a motor for driving a tool, at least three switching elements which are coupled to the controller, and a speed sensor for monitoring the speed of the motor to generate a speed signal, which is fed to the controller. The controller is configured so that, in dependence on the speed signal, with simultaneous activation of a first and at least one other of the switching elements, a control signal for changing the operating parameter is output, and that, in dependence on the speed signal, with activation of the first and at least one other switching element, a control signal for modified changing of the operating parameter is output (FIG. 2).

Abstract: Moderately accurate closed loop speed control of a universal motor is attained without the need for any type of speed sensor. Motor armature (across the brushes) voltage is sensed and supplied to a control circuit for processing along with sensed motor current and zero-crossing information. Integration of the motor armature voltage provides a value which is related to current motor speed. By adjusting the gating angle for triac actuation, the armature voltage integral can be maintained at a desired value associated with a desired motor speed. The sensed motor current is also integrated to provide a speed droop compensation value that is added to the desired value, and the gating angle for triac actuation is adjusted to move the armature voltage integral value to approach the summed value of the speed droop compensation value and desired value.

Abstract: A system of detecting position drift in the motor due to lost pulses. Due to imperfections in the motor, the timing of the commutation pulses is not uniform but forms a unique repeatable signature. The system identifies lost pulses by using a pattern recognition technique on the signature of the motor commutation pulse rate. By detecting when a pulse is lost, the system can apply a correction to the pulse count. Accordingly, the real time correction of the pulse count allows for the system to operate with significantly reduced mispositioning errors. In addition, the system requires far fewer calibrations.

Abstract: A motor control system for a two-phase brushless DC motor uses measured EMF voltage from the passive set of stator coils to control commutation. A microcontroller receives the EMF voltage measurement and compares it to a threshold voltage value, which may be speed-dependent for advance commutation at high motor speeds. A match of the EMF voltage measurement with the threshold value triggers commutation of the drive to the opposite set of stator coils. The microcontroller also has an up-down counter timer whose count value is compared to an external speed reference. Each match of the count value triggers a transition in a pulse-width modulated (PWM) drive signal. The duty cycle of the PWM signal establishes an average drive voltage that controls motor speed.

Abstract: A method for driving a DC motor includes generating a first voltage pulse, based on a pre-determined speed input and duty cycle, and configured to generate motor current of reference current value sufficient to achieve a desired speed according to the speed input. Subsequent pulses of the voltage are generated to maintain the current substantially within a range of the reference current. Another method includes sensing and comparing motor current to reference current value and generating an error signal therebetween, which is integrated over time to generate an integrated current error, which is compared with a reference pulse. Thereafter generating applied voltage pulses configured to: switch at each instance of the integrated current error exceeding or becoming less than the reference pulse value; generate a motor current sufficient to achieve a desired speed according to a pre-determined speed input; and having substantially zero average variation from the reference current.

Abstract: An apparatus for converting electrical energy into mechanical energy includes a plurality of iron segments disposed in a circular, generally donut-shaped body that is substantially non-magnetic, and which forms a rotor of an electric motor. Each of a first plurality of coils is attached to a housing and form a stator. Each coil includes a hollow center and is disposed around the body. The coils are pulsed on and off in a pattern to create a magnetic field that attracts the iron segments urging them sufficient to rotate the body. The body forms a rotor of the electric motor. A second plurality of coils are optionally included and energized in an opposite or offset pattern as compared to the first plurality to increase torque or aid in starting rotation of the rotor. A permanent magnet in the rotor is used to indicate the position of the rotor relative to the stator. The rotor includes a pair of horseshoe-shaped overlapping halves that fasten together.

Abstract: Device for controling an electrical motor mounted on the crossarm of a bridge circuit whose motor current is controllable with semiconductor components formed in a first bridge branch by an electromagnetic switching device and in a second bridge branch by two serially switched, opposite-phase timed semiconductor switches. The opposite-phase timing of both semiconductor switches creates an active freewheeling branch, thereby making a freewheeling diode unnecessary.

Abstract: Methods and apparatus for controlling a polyphase motor in implantable medical device applications are provided. In one embodiment, the polyphase motor is a brushless DC motor. The back emf of a selected phase of the motor is sampled while a drive voltage of the selected phase is substantially zero. Various embodiments utilize sinusoidal or trapezoidal drive voltages. The sampled back emf provides an error signal indicative of the positional error of the rotor. In one embodiment, the sampled back emf is normalized with respect to a commanded angular velocity of the rotor to provide an error signal proportional only to the positional error of the motor rotor. The error signal is provided as feedback to control a frequency of the drive voltage. A speed control generates a speed control signal corresponding to a difference between a commanded angular velocity and an angular velocity inferred from the frequency of the drive voltage.

Abstract: A position sensor generates a signal representative of the angular position and, if desired, angular velocity of a rotating object using only a single circular track and plural brushes that ride on the track when the object rotates. The single circular track can have plural segments, and the sensor can generate more than one signal cycle per revolution.

Abstract: A voltage sensor (101) is connected to output terminals (P, N) of a booster. The voltage sensor (101) detects a boosted voltage, and outputs the detected voltage to a first drive controller (102). The first drive controller (102) outputs a control signal to a variable resistor (22) indicating a gate resistance obtained on the basis of the boosted voltage. The variable resistor (22) is controlled to have the specified gate resistance in response to the received control signal.

Abstract: Domestic electrical appliance, including a universal electric motor powered by direct current via an electrical circuit linked to a DC electrical voltage source, said circuit including a chopper arrangement, including a capacitor in parallel with the DC voltage source, and one or more solid-state switches, wherein the circuit also includes two controllable switches, for automatically reconfiguring said circuit: a first switch, connected on the one hand, to a first terminal of a motor winding, and on the other hand, alternately to the DC voltage source and to the first terminal of the motor rotor; a second switch, connected on the one hand, to the second terminal of said motor winding, and on the other hand, alternately to one or to the other of the terminals of the motor rotor.

Abstract: A method is disclosed for controlling the commutation in an electronically commutated motor (20) which comprises a stator having at least one phase (24, 26), and a permanent-magnet rotor (22), and with which a current limiter (36, 58) and a controller (18) for regulating a motor variable are associated. The current limiter (36, 58) serves to limit the current (I) in the at least one phase (24, 26) to a setpoint value. The regulation by means of the controller (18) is accomplished by modifying the distance in time (W) between switching on (t1) and switching off (t2) of the current (i1, i2) in the at least one phase. In this method, the setpoint value to which the current limiter limits the current (i1, i2) in the relevant phase is modifiable.

Abstract: A brush type DC motor 10 having an armature 15 and positive and negative power leads is provided. The motor includes an RFI choke 12 as a transformer in series with at least one of the positive and negative power leads to amplify current such that rotation of the armature 15 can be detected based on monitoring a voltage relating to the amplified current. Conditioning circuitry 14 is constructed and arranged to condition the voltage for detecting rotation of the armature.

Abstract: In the present system and method, ZCP level signals of each phase voltage are first obtained. Among the detected ZCP level signals, some ZCPs are generated by phase back EMF, which are true ZCPs and other ZCPs by commutations, which are false ZCPs. The duration of the false ZCP level outputs varies with the excited phase current, inductance and back EMF of motors, the present invention utilizes fixed-width narrow pulse signals corresponding to the rising and falling edges of the ZCP level outputs in order to eliminate influences of the earlier disclosed motor parameters. These fixed width pulse signals make up the ZCP pulse signal. Because the first edge of the plurality of false ZCP level signal substantially corresponds to the switching-off signal of the commutated-off excited phase, a first false ZCP masking signal having pulses wider than the ZCP pulse signal are applied to mask the first plurality of false ZCP signals.

Abstract: A system 10 provides a variable output voltage to a DC brush motor. The system includes a DC brush motor 14, a DC voltage source 12, a step-up, step-down DC/DC converter 16 including a switch 18. The DC/DC converter is constructed and arranged to step-up and step-down voltage from the source to provide an output voltage to the motor between 0 and 42 volts. A control unit 22 is constructed and arranged to receive an input signal 20 and to control the switch based on the input signal to control the motor.

Abstract: The present invention relates to a device in an electronic driving dynamics control system, comprising an electromechanic transducer, especially an electric motor, a hydraulic pump, and an electric actuating unit for the transducer, said transducer including a magnetic or magnetizable stator and a rotor, as well as connections for connecting the actuating unit, and a commutation device for the actuation of electromagnetic windings of the rotor, said invention inhering the special feature that the commutation device comprises three or more commutating elements that are electrically connected to the respective connections so that the windings of the rotor can be actuated individually by the actuating unit, with at least one commutating element being connected to a change-over element that provides for an additional connection for connecting a rotational speed measurement devices.

Abstract: In the context of a single-phase universal motor, which has proven its worth in particular as an agile washing machine drive, the novel control provides for a substantial reduction in the remagnetization losses, rotary speed dependency, level of efficiency, and the fluctuations in the motor current pulsating at double the mains frequency, together with the resulting losses and production of noise in particular because of torque fluctuations and electromagnetically excited oscillations of the stator iron core. The motor is no longer operated by way of the phase-angle control, which is synchronized with the mains frequency, of a pulse-fired triac which is self-turning off with the current zero crossing and also no longer operated by way of the pulse duty factor of a chopper oscillating freely at high frequency.

Abstract: A motor controlling device for an AC/DC driven motor is used for an AC and DC motor. The motor controlling device comprises an AC/DC converting unit, a voltage stabilizing unit, a phase detecting/controlling unit, and a high voltage driving unit. The AC/DC converting unit receives an AC power source to convert the AC power source into a high voltage DC voltage. The voltage stabilizing unit receives the high voltage DC voltage to convert it into a low voltage DC voltage. The phase detecting/controlling unit detects a polarity of the permanent magnet to output a first detecting and a second detecting signals accordingly, so as to provide automatically a shut down protection when the motor is locked. The high voltage driving unit receives the first detecting and the second detecting signals to drive the motor accordingly.

Abstract: A motor control system creates a rounding effect on square wave phase currents which results in reduced acoustic noise. The control system includes a voltage source for providing a DC bus current, and an inverter. The inverter has a switching circuit for regulating the DC bus current to a fixed level. The switching circuit also forces consecutive phases of the motor to share the bus current at commutation. Forcing consecutive phases of the motor to share a desired amount of the DC bus current creates a “rounding” effect on the phase currents, which results in reduced acoustic noise. The preferred inverter has a plurality of transistors, and a control module. The control module selectively engages the transistors such that each phase of the motor has a phase turn-on point that occurs before a phase turn-off point of a preceding phase. The control module also pulse width modulates the transistors such that the DC bus current is regulated to the fixed level.

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: An apparatus and method of powering a light source are provided. The apparatus includes a motor, a voltage stabilizing circuit, and a light source. The motor includes a field assembly and an armature assembly. The field assembly includes an intermediate tap on a field winding that forms a variable field winding power source. The stabilizing circuit connects to the intermediate tap and includes a voltage regulator having an output that is connected to a light source to be stabilized.

Abstract: A rotation detector apparatus and a rotation control apparatus for the DC motor is disclosed wherein rotational operations of a rotor of the DC motor are controlled by detecting at least one of the rotational direction, the rotational speed, the cumulative rotation number, and the rotational position of the rotor. The pulsed output signal from at least one motor rotor rotation detector brush is processed by signal processing circuitry to regulate the at least one of the rotational direction, the rotational speed, the cumulative rotation number, and the rotational position of the rotor.

Abstract: Two motor fans are driven by two 4-pole direct current motors, respectively. Rotational speed of the two motors is controlled in three stages, namely low speed, intermediate speed and high speed. Specifically, at the time of low speed operation the two motors are connected in series with four poles, at the time of intermediate speed operation the two motors are connected in parallel with three poles, and at the time of high speed operation the two motors are connected in parallel with four poles.

Abstract: The present invention relates generally to the reduction of odd harmonics of phase angle controlled loads. One embodiment relates to an apparatus for reducing odd harmonic currents introduced into an alternating current (AC) supply by a load having a zero crossing detector and a processor coupled to the zero crossing detector. The zero crossing detector is coupled to the AC current supply for measuring voltage zero crossings of the AC current supply. The processor receives a user control signal for controlling the load, such as, for example, a speed control, determines phase angles required at the voltage zero crossings of the AC current supply to implement the user control signal, and selectively modulating the phase angles when they are in a predetermined range of undesired phase angles in order to selectively reduce odd harmonics within the AC current supply.

Abstract: A food texture control and protection system for electric motor powered blender includes a device adapted to receive a selection signal that is generated by input device. The device controls the speed of the blade according to a selected speed variation against time curve aiming at to provide variation in the food texture. The device controls the blender by phase controlling the power supply to the motor of the blender.

Abstract: The present invention regards an electronic device for controlling the electromagnetic self-braking current in reversible rotating electric commutator machines, fitted with an inductor winding and an armature winding, in which there are reversing means to control the functioning of the electric machine as a generator by mutual inversion of the polarity of said inductor winding and said armature winding. The device includes a switchable current control circuit and an excitation circuit distinct from each other. The control circuit includes an electric load, a power device for connecting and disconnecting said electric load in series in the input circuit of said inductor winding to dissipate the power produced by said electric machine when it functions as a generator, and a variable duration pulse generator for controlling the switching of said power device.

Abstract: In a multiple power source system of the present invention that has an inverter connected to a reactance, such as three-phase coils in a motor, a high voltage battery is connected with a low voltage battery via one transistor (Tr2) and one diode (D2) included in the inverter and one phase coil (U-phase coil) of the three-phase motor. The transistor Tr2 is turned on to make the electric current flow from the low voltage battery to the U-phase coil. The transistor Tr2 is subsequently turned off at a preset timing, so that the electric energy accumulated in the reactance, that is, the U-phase coil, flows through the diode D1 into the high voltage battery and thereby charges the high voltage battery. This arrangement enables the charging process from the low voltage battery to the high voltage battery without any complicated circuit structure for the voltage step-up. The three-phase motor may be unipolar driven with transistors connected to one side of the inverter.

Abstract: An automatic door operating safety system particularly used with garage doors is provided. A security timer for a powered overhead garage door causes the door to close after it has been opened for a predetermined time interval. Before timeout, the system will determine by its various sensors whether there is any activity within the area. Upon the absence of such activity the system signals the command for door closure.

Abstract: A novel method is proposed for controlling the torque of a PM brushless motor with sinusoidal back-emfs without current sensors by computing the required input phase voltages with measured rotor position and speed and known machine parameters. These voltages are fed to the machine at an angle computed in terms of input parameters and the phase voltage with respect to their back-emfs so that phase currents are aligned with their back-emfs to exactly mimic the performance of the current mode controller.

Abstract: A vacuum cleaner operates via power supplied from either an on-board battery or an AC power outlet. When the vacuum cleaner is operating by using the battery a controller monitors the voltage level in the battery and automatically shuts down the vacuum cleaner when the battery voltage has decreased below a preset level. This prevents a full drainage of the battery and increases its longevity. The controller that monitors the battery voltage level can be used with batteries of different voltages. The controller automatically determines which type of battery is being used and shuts down power to the vacuum cleaner motor after the appropriate amount of battery drainage.

Abstract: A method for braking a washing machine in accordance with the present invention comprising the steps of: setting up an initial data of a duty ratio corresponding to a detected speed and a rotating position; discharging a voltage of the capacitor filter during a duty-on cycle according to the duty ratio set up in the preceding step; and charging a voltage to the capacitor filter during duty-off cycle when the duty-on cycle of the preceding step is finished. As described above, the dynamic braking resistor is not used in the method for braking the washing machine according to the present invention so that the size and the production cost are reduced.

Abstract: Disclosed is a three phase BLDC motor driving circuit which makes a BEMF voltage generated in a motor lower than a voltage source and makes a difference between the BEMF voltage and the voltage source greater than a saturation voltage of a transistor. An emitter is coupled to the voltage source and a collector is coupled to a three phase coil so that the voltage between the emitter and collector of the transistor supplying a current to the three phase coil attenuates to a first level so as not to saturate the transistor.

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: In an electric or hybrid electric vehicle, a voltage monitor (102) is directly coupled to a traction motor (38) and/or generator motor (30) to detect a permanent magnet induced voltage within the motor at a predetermined speed and no load condition (300). A controller (100) compares the detected permanent magnet induced voltage with an expected reference voltage that represents an expected permanent magnet induced voltage at full magnetization and the predetermined speed (302). The controller produces an indication of magnetization based on the reference voltage, the detected permanent magnet induced voltage, and the predetermined speed. If the indication of magnetism reaches a predetermined threshold, the motor is made inoperable and/or a current to the motor is limited to prevent damage to components (306, 308, 310, 312, 314). Preferably, a user of the vehicle is made aware of these actions by an audible and/or visual indicator (308, 314).

Abstract: A motor drive control system suitable for control of a drive of a motor, such as a brushless motor or a linear motor, having a plurality of excitation phases, through the use of rectangular waves. A drive means is provided for producing an excitation signal to be supplied to each of the excitation phases of the motor and a control means for determining a direction of the excitation signal for each of the excitation phases and for conducting ON/OFF switching. The control means controls the rate of change of the excitation signal to be switched at the switching operation.

Abstract: The invention relates to a control system for a commutator motor which is operated by phase-fired control. Allocation of a first and second control device in a single operating state without transition makes it possible to obtain constant jolting rotation of said motor by continuously varied cutting of the half-waves into first and second area sections (8,7) of an alternative current voltage. The inventive type of control system can be used advantageously in electric screwing or drilling tools.

Abstract: A series motor with commutator is disclosed which is especially suited as universal motor for a braked power tool. The series motor comprises a switch for switching between a motor mode and a braking mode, wherein, in motor mode, at least one field winding is connected in series with an armature winding in a motor circuit, which is connected to an a.c. power source, and wherein, in braking mode, the at least one field winding and the armature winding form together a closed braking circuit disconnected from the power source. The secondary winding of a mains-operated transformer is connected within the braking circuit. This arrangement guarantees improved safety of the braking action.

Abstract: A rotational pulse signal generating circuit for a commutator DC motor is made up of a filter device for eliminating noise from the motor, a cutoff frequency of the filter device being variable depending on an external signal; a pulse shaping device for generating a ripple pulse indicative of a rotational number of the motor by wave-shaping an output of the filter device; and a clock generating device for generating a clock signal on the basis of the ripple pulse and a rotational condition signal of the motor, the clock signal being fed to the filter device for making the cutoff signal thereof variable.

Abstract: A control drive circuit or the like is provided that is capable of producing a drive output of a higher voltage than a drive power source voltage. A differential amplifier 39 that constitutes a differential amplifying section 14 generates a current Ia on the basis of a current I0 obtained with a constant current generating section 12 and signal waveforms Vina and Vinb inputted from a signal source S. Currents I2 and I4 are generated with a pre-drive section 16. The current I2 corresponds to part of the current Ia that is greater than 1/2·I0 and smaller than 3/4·I0. The current I4 corresponds to part of the current Ia that is greater than 3/4·I0. In other words, part of the current Ia that is greater than 1/2·I0 is divided at the threshold value of 3/4·I0 to obtain the currents I2 and I4. Different coils are driven on the basis of the currents I2 and I4.

Abstract: Disclosed is a motor drive system comprising a control voltage output portion receiving a first control voltage and a second control voltage from an external servo, and outputting a voltage that is proportional to a difference between the first and second control voltages; a driver receiving the voltage output from the control voltage output portion via a non-inversion terminal and receiving feedback signals through an inversion terminal to generate drive signals for a motor; a commutation distributor outputting ON/OFF signals such that the motor is optimally driven, the ON/OFF signals being output according to hole signals of each phase of the motor that are input externally; a power transistor, which is ON/OFF controlled according to an output of the driver to supply the drive signals to the motor; an output current detector detecting the drive signals output from the power transistor and converting the drive signals into a voltage, and outputting an output voltage; and a voltage amplifier, a voltage gain o

Abstract: A method and a circuit configuration for detecting the rotational speed of electronically commutated fans include measuring maximum current gradients of current fluctuations caused by the fan on its power supply lines, and adapting an amplification range and switching threshold of a comparator used as an input stage for a pulse former.