Abstract: A system and method for measuring the speed of a fan is presented. The duty cycle of a pulse width modulated (PWM) power signal may control speed of the fan. The fan may generate tachometer pulses used for monitoring RPM of the fan. Very low frequency test pulses may be generated and provided via a test signal multiplexed with the PWM signal to obtain tachometer pulses present even when the PWM signal is deasserted. The frequency of the test signal may be determined based on the duty cycle of the PWM signal and may be dynamically updated using frequency divider values stored in a user programmable look-up table. The tachometer pulses may be used to reset a flip-flop whose data input is held high and a down counter, which may be operated at a frequency slightly lower than the frequency of the test signal, with the output of the down counter clocking the flip-flop.

Abstract: A system includes a motor for producing motion when current is supplied to the motor and a motor controller coupled to the motor for receiving a motor current signal indicative of the current supplied to the motor. The motor controller has an analog-to-digital converter for converting the motor current signal to a sampled motor current signal. The motor controller is operable to detect pulses in the sampled motor current signal, count the detected pulses to generate a first pulse count, and determine a run parameter for the motor based on the first pulse count. A method for controlling a motor includes counting a first plurality of pulses in a motor current signal produced while the motor is activated to generate a first pulse count. A second plurality of pulses is counted in the motor current signal produced while the motor is deactivated to generate a second pulse count. A run parameter for the motor is determined based on the first and second pulse counts.

Abstract: A system and method for measuring the speed of a fan in an electrical system is presented. The duty cycle of a pulse width modulated (PWM) signal provided by a signal generator may control the speed of the fan. The fan may generate tachometer pulses that may be used by a tachometer reading-unit to monitor the RPM of the fan. Very low frequency test (VLFT) pulses may be generated and provided through a sampling signal multiplexed with the PWM signal to sample the fan generated tachometer pulses even when the PWM signal is low. The frequency of the sampling signal may be determined based on the duty cycle of the PWM signal and may be dynamically updated when the duty cycle of the PWM signal is updated. The sampling signal may be used as the clock input to a flip-flop with the tachometer pulses as the data input, and the output of the flip-flop providing an input to a pulse counter that counts the number of pulses within a determined period of time, providing as its output the measured RPM of the fan.

Abstract: A method and apparatus for controlling a fan is disclosed. In one embodiment, a method for controlling a fan includes applying power to the fan at startup. The fan may be supplied a predetermined amount of current, which may break the inertia of the fan propeller and begin its rotation. As the propeller begins rotating, the speed at which it rotates may be monitored. The fan startup routine may continue until the fan reaches or exceeds a minimum fan speed threshold. Once the fan has at least reached the minimum speed, the amount of current supplied to the fan may be reduced such that the fan rotates at minimum speed, and an automatic fan control algorithm may begin executing. By reducing the current such that the fan operates at a minimum speed, the amount of audible noise generated by the fan during startup may be kept to a minimum level.

Abstract: A drive circuit for brushless DC motors including a rotor and a stator with at least one stator coil includes a commutation device which supplies commutation pulses of drive current to the stator coil(s). The commutation device senses the rotor position and calculates current rotor speed therefrom. The rotor speed is then used to shift the commutation circuits according to predetermined functions. The shifting of commutation currents is occasioned by shifting either or both of the ignition part of a commutation pulse and the extinction part of such pulse.

Abstract: A device for correcting a digital estimate of an electric signal is described. The device includes a comparator that generates a current proportional to the difference between an analog estimate signal, which derives from the digital estimate, and the electric signal. The device also includes a capacitor positioned to be charged by the current, a transistor that discharges the capacitor, and a comparator that compares the voltage at the terminal of the capacitor with a reference voltage. The device also includes a controller that drives the transistor in response to the output signal of the comparator and a logic device that generates a correction digital signal to be added to or subtracted from the digital estimate of the electric signal in correspondence of an ascending or descending waveform of the electric signal.

Abstract: The present invention concerns a motor vehicle comprising at least one electric motor, an energy storage device for providing drive energy for the electric motor, a plug connector connected to the energy storage device for connection to a current source and a control means for controlling the flow of current from the current source to the energy storage device. Therefore the object of the invention is to provide a motor vehicle which can contribute to moderating the loading at consumption peaks in the network. A motor vehicle comprising at least one electric motor, an energy storage device for providing drive energy for the electric motor, a plug connector connected to the energy storage device for connection to a current source and a control means for controlling the flow of current from the current source to the energy storage device, characterized in that the control means permits a flow of current from the energy storage device to the current source (network).

Abstract: An electric fan temperature-rated variable speed control circuit, includes a D.C. current source and fan activation IC. There are, between the current source positive and negative poles serially connected transistor, regulation tube, with the regulation tube negative pole linked to the current source negative pole, and its positive pole, incorporated to form the primary current. Between triode base and collector lies a serially connected resistor. The triode collector is linked to the current source positive pole, and between its base and collector lies a serially connected rectifying resistor, which bypasses through the base to connect with the fan activation IC for sending out fan rotation speed control signals with which to form a circuit that adopts a straightforward, easy-to-implement method that offers low-cost and dependable temperature-control characteristics.

Abstract: A fan speed control includes a power adapter, a CPU programmed with a phase splitting program, a current-limit resistor, a capacitor, a TRIAC, and a switch module, the CPU having a signal input terminal connected in series to the power input terminals of the power adapter through the current-limit resistor to obtain synchronous signal frequency as input signal, a signal output terminal connected in series to the capacitor and then the gate of the TRIAC for enabling the CPU to control triggering of the TRIAC, the TRIAC having the gate connected in series to the capacitor, and the anode and cathode respectively connected to the fan motor and the power output terminal of the power adapter, so that the fan motor, the TRIAC and the power adapter form a loop in which the TRIAC controls the operation speed of the fan motor; the switch module having one end connected to the control input terminal of the CPU for controlling the output state of the signal output terminal of the CPU and the other end connected to the po

Abstract: When a signal level of a motor brush switching signal is low and thus dropouts or omission of the pulse signals converted by a waveform shaping part take place, so that an interval between a pulse signal to be currently counted and an immediately preceding pulse signal thereof becomes longer than a predetermined average interval, a pulse signal counter makes a correction of the number of counts by adding one pulse to the pulse to be counted. Therefore, even if the signal level of the motor brush switching signals generated from a vertical motion motor M2 is low for some reasons, accurate control can be exercised over the number of rotations of the vertical motion motor M2.

Abstract: A driving circuit for switches of direct current fan motor is disclosed. The driving circuit includes a plurality of switches, a first control circuit, and a second circuit. The switches are driven by a first pulse width modulation signal and a second pulse width modulation signal, and they are electrically connected with the direct current fan motor in a bridge manner. A third pulse width modulation signal is used to drive the first control circuit connected to at least one of the switches driven by the first pulse width modulation signal. A fourth pulse width modulation signal is used to drive the second control circuit connected to at least one of the switches driven by the second pulse width modulation signal. Especially, either the first pulse width modulation signal or the second pulse width modulation signal is selected as the third pulse width modulation signal or the fourth pulse width modulation signal.

Abstract: A radiator includes a voltage regulator for providing a reference voltage, a fan including a power end connected to the reference voltage via a first resistor and a feedback end for outputting a pulse signal indicating the rotation speed of the fan, an integration circuit including an output end, and an input end connected to the feedback end of the fan for converting the pulse signal from the feedback end into a voltage signal, and a thermistor connected between the output end of the integration circuit and the reference voltage, for detecting temperature changes in order to adjust the rotation speed of the fan.

Abstract: A powered tool for performing surgical procedures. The tool includes a handpiece in which a power generating unit is housed. A control member is mounted to the handpiece. The control member is mounted to the handpiece so that the orientation of the control member can be selectively set relative to the point to which it is mounted to the handpiece and so it can move relative to a reference point on the handpiece. A control module monitors the orientation of the control member and its position relative to the reference point. Based on the control member orientation and position, the control module generates signals to regulate the operation of the power generating unit. When the power generating unit is a motor, the control module generates signals to ensure that the maximum speed at which the motor can be driven is less than the no load speed.

Abstract: A brushless dc motor includes a conversion circuit and a dc motor drive circuit. The conversion circuit includes a rectifier unit, a pulse-wave-absorbing unit, a filter unit, a voltage-stabilizing control unit and a voltage-stabilizing unit. The rectifier unit, the pulse-wave-absorbing unit and the filter unit are serially connected between an ac power source and the dc motor drive circuit. The ac power source is rectified, stabilized and filtered to thereby supply with a dc voltage to the dc motor drive circuit. The voltage-stabilizing control unit and the voltage-stabilizing unit are serially connected between the rectifier unit and the dc motor drive circuit so as to limit a passage of a high voltage and to allow a passage of a low voltage through the dc motor drive circuit. Thereby, the voltage-stabilizing control unit and the voltage-stabilizing unit are commonly in control of the operation of the dc motor drive circuit.

Abstract: A method of driving an electrical load having a complex electrical impedance, such as a voice-coil motor controlling the position of a read/write head in a data storage disk drive system, comprises providing a voltage-mode driver generating drive signals for the electrical load in response to drive commands. Compensated commands for the voltage-mode driver are generated filtering the drive commands, compensating for a phase shift between electrical quantities delivered to the electrical load. The voltage-mode drive thus emulates a conventional, but more expensive, current-mode drive. In a preferred embodiment, the method comprises estimating characteristic parameters of the electrical load during the operation, and adapting the filtering to the estimated characteristic parameters. The estimation comprises implementing a Kalman filtering algorithm, particularly an extended Kalman filtering.

Abstract: A permanent magnet DC brushless motor control assembly permits a user to select the permanent magnet DC brushless motor operating characteristics by selecting appropriate control circuits to interface with the motor. The assembly includes a permanent magnet DC brushless motor, a commutator electrically coupled to the motor, and at least one control module electrically coupled to the commutator, to control operating characteristics of the permanent magnet DC brushless motor.

Abstract: Systems, methods, and apparatus, consistent with principles of the present invention, allow an unmodified device, for example, a dc starter motor, that normally operates at a first voltage to function in an electrical system providing a second voltage, which is different from the first voltage, and received from the power source. A device actuator, such as a solenoid, is controlled using the second voltage. The first voltage is produced and supplied to the device in response to a first action of the actuator, for example, upon solenoid depression. This voltage is then inhibited from being provided to the device in response to a second action of the actuator, for example, upon solenoid retraction after engine cranking.

Abstract: Various systems and methods are provided for cooling a cabinet. In one embodiment, a method is provided that comprises the steps of controlling a speed of the at least one cooling fan in response to a temperature of the cabinet, and, controlling the speed of the at least one cooling fan in response to a position of an access panel relative to the cabinet.

Abstract: There is provided a brushless DC fan motor which can eliminate an oscillator for PWM, control the motor speed at a low cost with high accuracy, and efficiently adjust the temperature in a housing for electronic appliances when radiating the heat in the housing. The brushless DC fan motor with the rotational speed thereof controlled by controlling the voltage of a control input terminal of a drive circuit comprises a differential amplifier in which the voltage signal for controlling the speed is inputted in a first input terminal and the reference voltage signal is inputted in a second input terminal. The differential amplifier is linear in the input-output characteristic, and can set the rise characteristic of a desired gradient, and control the motor speed with high accuracy without using the PWM signal for the input signal. The voltage signal from the output terminal of the differential amplifier is given to the control input terminal of the drive circuit.

Abstract: A DC motor control device of a water heater includes a fanner control system, a rotation speed detection circuit, and a micro-processing unit. The fanner control system has a DC motor and a control circuit unit. The rotation speed detection circuit is connected to the DC motor for detecting the rotation speed of the DC motor. The micro-processing unit is connected to the output terminals of the rotation speed detection circuit. The output terminals of the micro-processing unit are connected to the fanner control system. The micro-processing unit is to process outputs of the rotation speed detection circuit and then output a low DC voltage to drive the DC motor, thereby having an optimal rotation speed.

Abstract: Torque generating apparatus and method for automotive applications. A brushless DC motor is design optimized to operate at a design voltage, Vs, along an optimal speed/torque profile. A DC/DC converter is provided for supplying power at an alternate voltage, Va, to enable motor operation at speed/torque combinations not on the optimal profile. A switch is provided to enable the motor to be operated selectively at either of the two voltages.

Abstract: A brushless, synchronous direct current motor is operated by supplying a direct current voltage as an input voltage for commutating the motor phase windings. The speed of the synchronous motor is modified or varied in two speed ranges. In the first speed range, a linear change of the input voltage is carried out up to a speed threshold value. In the second speed range with higher speeds than in the first speed range, a vector modification of the input voltage is carried out, for example for controlling the speed of a fan motor.

Abstract: At the time of controlling a servo mechanism, a servo control detects that the position of a driven body is in the steady judgment region of a target position and varies a control constant (PI value) in the steady judgment region, so it is made possible to reduce an oscillation of the driven body in the steady judgment region.

Abstract: A control circuitry, electrically connected to a DC motor and a variable voltage source for modulating a rotational speed of the DC motor. The control circuitry includes a voltage reference component and a switching circuit. The voltage reference component is electrically connected with the variable voltage source and provides a predetermined reference voltage. The switching circuit is electrically connected with the DC motor and the voltage reference component. The switching circuit is “OFF” when a voltage given by the variable voltage source is lower than the predetermined reference voltage so that the DC motor operates with a first operation mode, and the switching circuit is “ON” when the voltage given by the variable voltage source is higher than the predetermined reference voltage so that the DC motor operates with a second operation mode.

Abstract: An apparatus for controlling a rotational speed of a motor, coupled to a sensing unit capable of outputting a sensing signal. The apparatus includes a controlling unit, coupled to the sensing unit, for outputting a controlling signal according to the sensing signal and independently of the rotational speed of the motor. The controlling signal is a square wave and has a duty ratio that is determined by the sensing signal. The apparatus also includes a driving unit, coupled to the controlling unit, for outputting a driving signal to a motor rotor according to the duty ratio of the controlling signal. The driving signal also is a square wave. The rotational speed of the motor rotor is determined by the duty ratio of the driving signal.

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 circuit for providing feedback regarding the torque on an AC electric motor. A sample and hold circuit provides DC voltage information regarding the voltage drop across a resistor wired in series with the windings of the motor. Reference voltage from the sample and hold circuit may be supplied to a comparator, such as an operational amplifier, along with a voltage reading from a fixed rate charging circuit. A pulse is provided to a microcontroller each time the voltage of the fixed rate charging circuit equals the reference voltage, and the fixed rate charging circuit is discharged. The microcontroller uses the frequency of the pulses to determine the load on the motor.

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

Abstract: A laser level with a sensorless DC motor controller having a feedback sampling circuit connected in parallel with the coil to sense back EMF. An integrator provides a feedback signal from the sensed back EMF, which the amplified difference from a reference level is used as a pulse width control signal. A pulse width modulation generator uses the control signal to generate variable “on” time pulse widths for each motor drive pulse such that high resolution is provided to the DC motor, permitting accurate rotor position at low rotational speeds. It is emphasized that this abstract is provided to comply with the rules requiring an abstract to allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that is will not be used to interpret or limit the scope or meaning of the claims.

Abstract: A power driver for driving a signal on a load using voltage-mode driver. A system processor generates commands indicating a programmed drive signal desired from the voltage-mode driver. A VBEMF compensator determines a compensated command to compensate for the back electromotive force voltage produced by the load. The compensated commands are coupled to the voltage-mode driver, such that the voltage-mode driver generates a voltage output based upon the compensated command.

Abstract: Various embodiments of an electrical motor, a brushless DC motor controller, and applications thereof. In one embodiment, a fluid-moving device is provided with a brushless DC motor and a motor controller. The controller may include a set of comparators and a clocked digital circuit. The set of comparators are each configured to determine a voltage polarity on a respective winding of a stator. The clocked digital circuit is configured to receive polarity signals from the comparators and configured to detect in the polarity signals zero crossings having an expected crossing direction. The clocked digital circuit is also configured to determine a commutational sequence for energizing windings on the stator. Other embodiments may include a disk drive, an implantable medical device, a vehicle, and a downhole tool.

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

Abstract: A ventilation assembly for a motor vehicle comprising first and second motor fan units (1, 2) and a control device (5) adapted to vary the ventilation power (P1+2) developed by the assembly formed by the two motor fan units according to a desired total power value (PTC). The control device (5) comprises an electric power variator (7) with continuous power variation, connected to the first motor fan unit (1), and a means for cutting-off the supply of the second motor fan unit (2), the power (P2) developed by the said second motor fan unit (2) being either zero or equal to its maximum operating power (PM2).

Abstract: The invention relates to a method and system for linear speed control for electric direct current motors, in which digital to analog converter circuitry is used for converting an 8-bit digital signal to an analog voltage for setting voltage across a motor, a digital state machine means is used for converting the duty cycle of an input signal for output to the digital to analog converter means, and a closed loop feedback means is used for monitoring and setting the voltage across the motor. An over-current sense circuit can be used for monitoring the current across or passing through the electric motor. An over/under voltage sense circuit can be used for monitoring voltage of the electric motor. The resulting 8-bit digital control signal is converted to an analog voltage for the electric motor.

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: The present invention provides a method for shifting the instant of commutation for a sensorless and brushless direct-current motor (1), whose stator windings are fed by a multi-phase converter connection. The converter connection includes an output stage control (2), a commutation logic (3), a phase selector (4), and phase discriminator (5). A commutation detection (6) is supplied at one input (46) with the instantaneous value of the voltage induced in a phase, the instantaneous value being determined by the phase selector, and at a second input (47), with a reference voltage (Uref) for comparison. The reference voltage (Uref) can be changed by a commutation shift (7) in correspondence with a specific characteristic curve (71). A manipulated variable (Ust) is supplied by a manipulated-variable calculation (8) to the commutation shift (7) as a function of the setpoint speed (Nsetpoint) of the motor. The commutation shift takes place in an advantageous manner in a parabola shape.

Abstract: A fan motor driving circuit of the present invention comprises a device for detecting a power source voltage and outputting a voltage in proportion to a difference between the power source voltage and a predetermined rated voltage when the power source voltage is greater than the rated voltage. The driving circuit also includes a device for controlling a rotary speed of a fan motor to a predetermined value by automatically varying a first signal input to a conducting current generating circuit for determining the rotary speed of the fan motor according to an output voltage of the power source voltage detecting means when the power source voltage is greater than a predetermined value.

Abstract: A system for controlling the speed of an arm of a disk drive, including a feedback circuit for generating a feedback signal representative of the speed of the arm, and a drive circuit for comparing the feedback signal with a predetermined command signal representing a command speed, and adjusting a drive signal for a motor to drive the arm at the command speed. The feedback signal, which represents the back EMF of the motor, is compared with the command signal to determine an acceleration state of the arm and the acceleration state is used with a previous acceleration state to determine whether to adjust a predetermined level at which the motor is driven.

Abstract: A sensorless speed control apparatus and method for a brushless dc (BLDC) motor. A speed detection unit detects fluxes of respective phases of the BLDC motor, measures a period of the detected flux changes, and determines a speed of the BLDC motor. A subtractor subtracts an inputted reference speed and the detected speed outputted from the speed detection unit, and outputs an error speed. A speed controller outputs a reference current corresponding to the error speed outputted from the subtractor. A current controller outputs a control signal for controlling the switching operations of an inverter based on the reference current outputted from the speed controller. The inverter applies a current of variable frequency to the respective phases of the motor based on the control signal outputted from the current controller, and drives the motor.

Abstract: An electrical hand-tool device and start-up safety routine protecting against start-up blockages, in which an electrical motor is connected, for a short time span (T0), with the current supply at a determinable resistance. At least one of a limit value (&agr;G) and a shut-off point in time (tA) is determined, for the safety routine in the event of tool blockage, using a measurement of the angle of rotation (&phgr;) of the rotor taken over the time span (T0) dependent on the start-up behavior of a rotor in the time span (T0).

Abstract: A powered tool for performing surgical procedures. The tool includes a handpiece in which a power generating unit is housed. A control member is mounted to the handpiece. The control member is mounted to the handpiece so that the orientation of the control member can be selectively set relative to the point to which it is mounted to the handpiece and so it can move relative to a reference point on the handpiece. A control module monitors the orientation of the control member and its position relative to the reference point. Based on the control member orientation and position, the control module generates signals to regulate the operation of the power generating unit. When the power generating unit is a motor, the control module generates signals to ensure that the maximum speed at which the motor can be driven is less than the no load speed.

Abstract: A circuit for the speed recovery of a direct current motor includes an output stage, output stage having a first pair of transistors, a second pair of transistors, and means a first circuit configured to detect a current circulating in the motor. The output stage further includes a second circuit configured to, activate the second pair transistors for a determined first time period so as to short-circuit the motor, and, at the end of the first time period, unbalance the output stage so as to force a maximum current to circulate for a determined second time period as a function of a value detected by the first circuit during the first time period, so as to stop the motor.

Abstract: A motor control system 10 includes an engine cooling module 14 including a DC motor 12. The system includes a switch 18 constructed and arranged to be controlled by a pulse width modulated (PWM) signal 26. The switch 18 is operatively associated with the DC motor to control current to the DC motor and thus control the speed of the DC motor. A controller 20 is operatively associated with the switch. The controller is constructed and arranged to select periods, of a limited-pool of frequencies each being less than 500 Hz, from a pseudo-random sequence of periods and to send the selected periods to the switch, thereby controlling noise and vibration of the module.

Abstract: A method and system for DC motor control is provided. A processor controls transistors connected to the field and armature coils of a DC motor, and measures the current and average voltage associated with said field and armature coils to determine motor speed. Motor speed is compared to a speed command to determine a speed error. The torque of the motor is adjusted to reduce the speed error. Safety features and power redistribution features are also provided.

Abstract: A simple control circuitry is provided for controlling the rotational speed of a DC motor. The control circuitry includes a voltage reference component and a switching circuit for controlling the state of the voltage reference component. When the voltage of the DC motor and the voltage reference component is no higher than a predetermined voltage level of the voltage reference component, the switching circuit does not conduct, and the DC motor is accelerated according to a first operation mode. When the voltage of the DC motor and the voltage reference component is higher than a predetermined voltage level of the voltage reference component, the switching circuit conducts, and the DC motor is accelerated to a maximum speed according to a second operation mode.

Abstract: Disclosed is control circuitry for providing controlling a motor responsive to feedback signals. The control circuit includes a velocity sensor for coupling with the motor for providing a velocity feedback signal responsive to the velocity of the motor, and circuitry for providing a feedback signal responsive to a voltage associated with the motor, such as the back emf of a coil associated with the motor. The control circuitry can be used enhance the Z-axis control of a tool of a work apparatus for performing work operations on a work material, such as a cutting apparatus for cutting a sheet of vinyl having a releasable backing for generating graphic products.

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 (I) of the DC motor field (57). The other end (K) of the DC motor field (57) is connected (59a) through a plurality of diodes (61-63) to respective phases of the input power.

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 constant speed control circuit for a fan includes a timing control unit, a driving unit and a fan speed control (FSC) unit. The fan speed control unit receives an external frequency signal from a frequency generator, which represents an expected rotational speed of the fan. Based on the external frequency signal, the FSC unit generates an adjusting signal that is input to the timing control unit. After the timing control unit compares a Hall signal with the adjusting signal, driving signals are generated and provided to control the activation time of transistors of the driving unit. Thereby, the fan is operated at a constant speed status.

Abstract: A decelerating method with low power consumption can be selected when rapid deceleration is not required. A disk can be stopped promptly and reliably even when a need arises for stopping the disk during deceleration of the disk by the method with low power consumption. In a disk device having a function of decelerating or stopping a rotating disk, depending on the kind of a command upon decelerating or stopping, the operation for decelerating or stopping is switched between a forced deceleration or stop operation by applying a reverse-directional voltage to a disk motor which rotates the disk so as to forcedly decelerate or stop the disk, and a power saving deceleration or stop operation with lower power consumption than the forced deceleration or stop operation so as to decelerate or stop the disk.