Abstract: When a processor sets a current instruction value and a rotating direction of a motor, two analog instruction signals of a positive polarity and a negative polarity are obtained after completion of a D/A conversion, the analog instruction signal of the negative polarity is selected by an instruction in the CW direction, and the analog instruction signal of the positive polarity is selected by the instruction in the CCW direction. The analog instruction signal of the polarity selected is added to a motor current detection signal which was negatively fed back by an adding circuit, so that an analog deviation signal is derived. A pulse width modulating circuit section outputs a PWM pulse in the CW direction for the negative polarity of the analog deviation signal and outputs a PWM pulse in the CCW direction for the positive polarity.

Abstract: In a current command type PWM inverter apparatus including first to sixth main circuit switching power devices for supplying line currents to a three-phase motor, at a periodical state updating first timing, and at least one second timing when any one of first, second and third comparison signals between respective detected line currents and respective line current command signals change after the state updating first timing, a logic circuit generates and outputs first to sixth switching command signals to the main circuit switching power devices so as to minimize errors between respective line current command signals and respective detected line currents.

Abstract: A control strategy for an electronically controlled X-Y shifting mechanism for a vehicle transmission which takes advantage of the extra supply voltage available on European vehicles while maintaining commonality with U.S. shifter systems. A variable voltage pulse width modulated duty cycle percentage is maintained at or below a 50% nominal value to make the 24V source appear as a 12V source, allowing commonality in X-Y shifting mechanism hardware and basic control algorithms for both 12V and 24V vehicle systems. However, this percentage is increased to greater than the nominal 50% limit when the available supply voltage drops below 24V, as well as between an initial movement of the shift finger and engagement of the finger with a shift block, in order to provide faster motor acceleration to obtain top speeds quicker and during low force but top speed movement conditions.

Abstract: A method for controlling the speed of a motor driven by an unregulated voltage supply is disclosed. The disclosed method comprises obtaining a ripple signal (V.sub.R) representative of the ripple component of the supply voltage, and modulating the motor current (I.sub.M) in response to at least the ripple signal to maintain the speed of the motor at a prescribed target speed.

Abstract: A circuit for controlling a rotating member is provided with an input capture register which reads out the value of a free running counter at a timing of an FG (frequency generated) pulse generated in accordance with a rotation of a rotating member. A central processing unit performs an interrupt operation based on a PG (phase generated) pulse generated in accordance with a rotation of the rotating member and an interrupt operation based on the FG pulse. A pulse width modulation circuit rotates the rotating member by use of a speed error signal and a phase error signal which are obtained by the interrupt operations of the central processing unit. A rotating member driver is also provided. The central processing unit calculates the phase error signal from an output of the input capture register based on an FG pulse generated after the generation of the PG pulse.

Abstract: A speed control for controlling the speed of a DC motor provides improved speed regulation during transient loading conditions. The control includes a regulating circuit having an output for controlling the armature voltage to the motor, An input speed reference signal corresponding to the desired speed is provided to the regulating circuit. A feedback signal proportional to armature voltage is also provided to the regulating circuit to establish an error signal for operating the control to regulate the voltage to the motor and therefore the motor speed, An IR compensating circuit provides increased motor voltage when the load increases. The voltage drop due to the armature circuit inductance is measured directly and also utilized to alter the output of the regulator to compensate for the inductive voltage drop occurring under transient loading conditions in a manner tending to establish the speed at the desired speed corresponding to the speed reference signal, during such conditions.

Abstract: A motor controller is provided which improves response to control inversion of a motor, and which also improves controllability and driving comfort when applied to electric power steering. In the motor controller a bridge circuit 5 is formed which includes switching elements 3a to 3d which are driven to control the motor 2 in a direction of conduction, a drive system is switched between a single-phase one-sided chopper system and either a single-phase double-sided chopper system or a double-phase double-sided chopper system based on detected states of an apparatus or the amount of control, so as to control the motor 2 with a drive system suitable for each state of the apparatus.

Abstract: A method for controlling the speed of a motor driven by an unregulated voltage supply is disclosed. The disclosed method comprises obtaining a ripple signal (V.sub.R) representative of the ripple component of the supply voltage, and modulating the motor current (I.sub.M) in response to at least the ripple signal to maintain the speed of the motor at a prescribed target speed.

Abstract: A cold therapy system for applying a cooling pad to an area of the body of the user. The system comprises a portable insulated cooler having a lid and serving as a reservoir for water and ice. A pump is located within a housing affixed to the exterior of the cooler. The pump has an inlet operatively connected to the reservoir through the adjacent cooler wall. The pump has an outlet connected by an insulated delivery tube to the inlet of a pad. The outlet of the pad is connected by an insulated return tube, through the cooler wall to which the pump housing is affixed, to the reservoir. The pump is provided with a pulse-width modulating circuit having an electronic switch output that switches an intermittent drive current to the pump motor according to any one of a number of predetermined operating modes selectable by the operator through the use of a manual switch.

Abstract: A device for the optimizing of the speed control of an electric subfractional horsepower motor for dental instruments is provided wherein it is possible to operate the motor in any desired speed range. The device contains a first module for regulating the speed by voltage measurement, a second module for regulating the speed by current-load compensation, and means for deciding which of the two modules and in what proportion they assume speed regulation of the motor.

Abstract: A vector control board for an electric vehicle propulsion system motor controller comprising a microcontroller for generating torque requests, a digital signal processor for receiving the torque requests from the microcontroller and for generating phase voltage signals in accordance with the torque requests, and a digital gate array for receiving the phase voltage signals from the digital signal processor and for generating gate drive signals from the phase voltage signals.

Abstract: A method and apparatus for the low noise operation of a electrical machine driven by a pulse inverter computes the amplitudes and frequencies of the harmonics of the inverter output voltages. Through targeted setting of the modulation parameters, the frequency spectrum or the noise spectrum can be fanned out and harmonics, which would excite stator resonances, can be eliminated. Due to the independence of the modulation parameters from the modulation index (a.sub.0) and the fundamental oscillation frequency (f.sub.1), the fanning-out and the elimination has no influence on the fundamental oscillation (u.sub.GS) or on the operating point of the machine. The inverter is controlled through sinusoidal pulse width modulation (PWM) and sinusoidal pulse frequency modulation (PFM) of a triangular carrier signal (U.sub.H). By this method, the main groups of the harmonics with two ordinate numbers (n, v) are fanned out into subgroups with three ordinate numbers (n, m, v).

Abstract: An apparatus for carrying out a current control and method therefor are disclosed in which the current control is such that no 0 vector defect is present by switching from a three-arm modulation method to a two-arm modulation method in the vicinity to a voltage saturation in a PWM inverter using the three-arm modulation method. The structure of the current control apparatus is such that in the PWM inverter using the three-arm modulation method having a time point data preparing section which prepares a time point data for the three-arm modulation mode from voltage vector times T .lambda., T.mu.

Abstract: A motor assembly includes a brushless dc motor and a driving unit. The driving unit includes three first power transistors, each being activable to connect a respective one of three windings of a coil unit of the dc motor and a power supplying circuit. A comparing unit compares a reference voltage signal equal to a desired motor speed from a speed setting unit with an analog voltage signal corresponding to the rotating speed of the rotor from a frequency-to-voltage converter and generates an analog error voltage signal. Each of three second power transistor corresponds to one of the first power transistors and is activable to connect the power supplying circuit and a respective one of the windings of the coil unit.

Abstract: A control circuit for a series type dc motor. The control circuit uses a switching cell to control motor speed. The switching cell and motor receive power from a filtered dc supply. A tachometer generator produces a voltage proportional to motor speed. The speed voltage is compared to a speed reference signal voltage and the difference is proportionally integrated to develop a speed error signal voltage. The speed reference signal voltage is developed at a summing node where a current generated by the control's microcontroller is summed with a current proportional to the input ripple voltage of the control's dc supply. The microcontroller also receives a voltage proportional to the control's dc input as a reference. The speed error signal voltage is compared with the output voltage of a current sensor that is in series with the motor feeder arrangement and the comparator's output is used to reset a bistable flip flop.

Abstract: A control system for a radio controlled model includes an onboard speed controller, an onboard receiver, and a separate transmitter unit having a throttle/brake trigger or other manually moveable member that an operator can move from a neutral position over a range of speed setpoint positions and a range of braking setpoint positions in order to input speed and braking setpoint information. At least one of the speed controller, the receiver, and the transmitter unit is programmed or otherwise arranged to produce a nonlinear speed controller response such that (i) the speed controller responds to an incremental increase in speed setpoint position of the moveable member near the neutral position with a smaller incremental increase in drive circuit duty ratio than when the speed controller responds to such an incremental increase in speed setpoint position near a MAXIMUM speed setpoint position (i.e.

Abstract: Provided is a brushless DC motor speed controller in which the speed feedback signal needed for speed control is obtained from the commutation signals generated by the magnetic-pole sensor in the brushless DC motor. The-brushless DC motor speed controller includes an edge detector, which generates a pulse each time a rising or falling edge is detected in the signal from the magnetic-pole sensor of the brushless DC motor. A frequency multiplier is used to multiply the frequency of the pulse train from said edge detector. A frequency-to-voltage converter is used to convert the output pulse train from said frequency multiplier into a positive analog voltage, with the level of the positive analog voltage being in proportion to the speed of the brushless DC motor. A motor rotating direction detecting circuit receives the output signal from said magnetic-pole sensor and thereby detects in which direction the brushless DC motor currently rotates.

Abstract: A power supply apparatus for an electric vehicle, which is adapted to restrain battery discharge due to current pulsations of a load. The apparatus has a battery, a coil and a capacitor connected to the battery via the coil to supply power. The apparatus controls the burden ratio of discharge current between the battery and the capacitor in accordance with various operation modes of the electric vehicle to extend a travelable distance thereof.

Abstract: A PLL system has a phase comparator for converting the phase difference between a reference clock signal and a feedback clock signal corresponding to a PWM signal Into a binary value, a frequency comparator for converting the frequency difference between the reference and feedback clock signals into a binary value, an automatic gain controller for adjusting the loop gain of the PLL system to a given value whenever the output of the frequency comparator reaches a change point, and a PWM signal generator for generating the PWM signal according to the outputs of the phase comparator, frequency comparator, and automatic gain controller. These components of the PLL system process digital signals, to simplify the structure of the PLL system, expand the range of loop gains to be set, and speedily synchronize the feedback clock signal with the reference clock signal.

Abstract: A method for controlling the speed of a motor for a tape drive in a mailing machine includes providing an optical sensor for signaling the appearance of slots in a slotted wheel connected to the motor shaft. The time intervals between slots are used to make a prediction in respect of expected future time intervals and the motor speed is adjusted in accordance with the predicted value to obtain the desired value. For best results, the data is received at the microprocessor using the "capture" mode of operation in order to avoid excessive errors due to a "busy" processor. The invention enables the small motor of a tape drive to avoid over and undershoot even when operating under highly variable load conditions.

Abstract: A method for calculating a speed estimated value in a speed control system, comprises the steps of: (a) storing the number of speed detection pulses obtained at each interval of a speed control process and time that the speed detection pulse was obtained; (b) calculating a detection speed from the number of latest speed detection pulses and its detection time, and the number of the previously stored speed detection pulses and its detection time; (c) executing an averaging process of motor model output corresponding to time that the detection speed was obtained; (d) obtaining a difference between an output obtained at said step (c) and the detection speed; (e) executing a calculation of a load torque estimation by multiplying the difference of the step (d) by an observer gain; (f) executing an estimation of a motor speed for next processing from the difference of the step (d) and a difference between the detection speed and the motor model output; (g) calculating an output of a speed amplifier by constituting

Abstract: An apparatus for controlling a drive circuit having a supply of electric power from a power source to drive an electric motor. The drive circuit includes at least one switching element operable between a first state connecting the electric motor to the power source and a second state disconnecting the electric motor from the power source in the second state. An overcurrent detection signal is produced when the current flow through the electric motor exceeds a predetermined value. In the presence of the overcurrent detection signal, the switching element is changed to the second state. The switching element is fixed in the second state when the repetitive period of the overcurrent detection signal is less than a predetermined value to avoid an excessive amount of heat generated from the switching element because of transient power losses.

Abstract: A circuit for controlling a current in a load, the circuit includes: structure for connecting the circuit to a source of power, the power source connecting structure including a power switch having off and on operating modes; structure for connecting the circuit to a supply of a pulse width modulated (PWM) control signal, the PWM supply connecting structure including an AND gate having first and second input structure and an output structure, one of the first and second input structures connected for receiving the PWM control signal, and the AND gate output structure connected to the power switch for operating the switch; structure for monitoring the current in the load, the monitoring structure including a differential amplifier, the differential amplifier having an instantaneous output voltage signal proportional to the load current when the power switch is in the on operating mode, structure for comparing a value derived from the instantaneous signal to a high reference voltage signal and a low reference v

Abstract: The rotation speed of a brushless motor is detected to generate a signal synchronizing with the rotation of the motor, and, on the basis of the synchronizing signal, a plurality of duty signals representing respectively different duty factors are generated. One of the plural duty signals is selected according to the detected rotation speed of the motor, and, on the basis of the selected duty signal, a corresponding exciting signal is supplied to the motor. The higher the detected rotation speed of the motor, the selected duty signal represents a larger duty factor.

Abstract: A general purpose or universal motor control is constructed as integrated circuit using a plurality of state machines and memories. The specific characteristics of a motor are programmed into a programmable "features" memory. A lookup table contains parameters for operating the motor that are accessed as a function of the features. The features memory and the lookup table may be programmed and tested through a communications state machine. External and internal pulse width modulation is provided along with dynamic braking as options that are utilized by the state machines depending upon the features. A multiplexer acts a switch between the state machines, the memories and the motor drive.

Abstract: In case an instantaneous over-current flowing through switching elements is detected between a predetermined rise time point and a predetermined fall time point of each of the PWM control pulses, the output of the duty control circuit is stopped immediately. In other words, the duty factor of the PWM pulse signal to be outputted as it is under the normal conditions is reduced so as to be cut off after the over-current has been detected. Therefore, it is possible to protect the switching elements of the inverter from breakdown due to over-current, without stopping the operation of the compressor and the compressor motor.

Abstract: A method and system for estimating an inertia of 2-mass system constituted by a motor and a load connected through a torsionable shaft during operation. The estimating method is implemented as follows: (a) obtaining a deviation between a motor speed preset value and a motor speed in a deviation section; (b) inputting the deviation from the deviation section into an adding section through a speed control amplifier; (c) obtaining a motor generating torque by inputting the output from the speed control amplifier and the load torque estimate into an adding section; (e) inputting the motor generating torque into a model of the 2-mass system; and (f) obtaining an inertia error by inputting the load torque estimate into the inertia error estimating section. With this method, it becomes possible to estimate the inertia of the 2-mass system even if the load inertia is varied during operation.

Abstract: There is disclosed an electronic display unit wherein a motor driving portion including a CPU and a driving IC controls a drive current to a motor (11) so that the motor (11) initially rotates at a low speed and subsequently rotates at a high speed to switch the speed of rotation of a case (3) from a low speed to a high speed, whereby operability is ensured if a rotation control switch is disposed on a front surface of the case (3), preventing conventionally increased size of the unit as well as alleviating user's feeling that rotation requires too much time.

Abstract: An apparatus that detects a reference position of a throttle valve. The throttle valve is forced in either a valve opening direction or a valve closing directions by an urging member. A DC motor, which is connected to the throttle valve, drives the throttle valve against the force created by the urging member within a rotatable angle that is restricted by a stopper. A throttle valve opening sensor detects an opening angle of the throttle valve. A lock current detecting circuit detects a lock current created by the DC motor when the DC motor is brought into contact with the stopper. A throttle valve reference position renewing circuit updates the reference position, which is memorized in a throttle valve reference position memory, on the basis of an opening angle of the throttle valve, which is detected by the throttle valve opening sensor, when the lock current detecting circuit detects the lock current.

Abstract: A power tool such as an electric drill typically contains a gear train that couples the output spindle of the motor to the tool bit-receiving chuck and has associated therewith a degree of looseness which must be taken up before torque from the motor is applied to the tool bit. The control circuit for the power tool increases the effective torque output of the tool after a predetermined torque level is attained, by alternately turning the motor on and off, with the duration of the off-time sufficient to permit the gear train to relax, thus giving the motor a "running start" when power is reapplied. Various alternative schemes for transitioning to this ratcheting mode of operation are disclosed including the sensing of a predetermined threshold current, a predetermined increase in motor current, and a predetermined rate of deceleration in motor speed.

Abstract: The invention relates to a recording apparatus for effecting recording on a recording material. The recording apparatus comprises a stepping motor, a recording head capable of reciprocating along the recorded material by a drive force of the stepping motor to effect recording on the recording material, an angular position detector for detecting a rotated angular position of a rotor of the stepping motor, a controller for controlling drive of the stepping motor in a closed-loop manner dependent on the detected result of the detector, a controller for operating the stepping motor in a mode of stepwise motor drive, a movement position detector for detecting a movement position of the recording head, and switching circuitry for switching over between the closed-loop control and the stepwise motor drive dependent on the detected value of the movement position detector.

Abstract: A solid state, electric motor control circuit is provided in conjunction with a solid state throttle and vehicle sensor circuit that together incorporate; a Hall Effect throttle position sensor circuit, a throttle position signal amplifier circuit, a vehicle reverse condition circuit, a vehicle operation inhibit circuit, a pulse width modulation circuit, and inverting MOSFET driver circuit, a plurality of power MOSFET devices, a voltage regulator circuit, and a current delivery circuit associated with an external DC electric motor. These circuit elements combine to translate a mechanical throttle position into a voltage level signal that can be converted by pulse width modulation circuitry into a pulsed wave form signal that suitably drives a bank of MOSFET, solid state switches so as to control the flow of current through a DC electric motor.

Abstract: A method of cyclically accelerating an electric motor particularly for use in a laundry machine. A desired speed, direction of rotation and acceleration time is set and power is applied to the motor in a series of incremental steps, each successive step corresponding to an increase in the level of power applied during the previous step. The steps are initially estimated to be sufficient to enable sufficient energy to be supplied to the motor for it to reach the desired speed in the desired acceleration time. The speed of the motor is monitored and the steps of accelerating the motor are repeated with the series of incremental steps adjusted to adjust the supply of energy to the motor dependant on the speed reached in the acceleration time of the previous cycle.

Abstract: A speed controller for a DC motor minimizes speed droop and load droop through pulse width or frequency modulation. The controller provides an extra power increase upon engine starting or whenever a heavier load is temporarily encountered. The control circuit also has a current limiter, overload indicators, and a battery recharger. The controller is very inexpensive, primarily because all of the timing components are contained on a single integrated circuit timer chip such as a 556 timer. The controller contains other features, including a circuit for limiting the pulse width of the control signal from the pulse width modulator.

Abstract: An electric motor control system has a motor driver comprising a bridge of switching elements, a pair of failure detectors, and a microcomputer. The motor driver is connected between a battery and an electric motor that is connected between the switching elements. The switching elements are turned on and off according to drive pulse signals supplied from the microcomputer for supplying a pulsed current to the electric motor. The failure detectors monitor the electric energy supplied to the electric motor to detect a period of time in which the supplied electric energy is free of pulses, and supply a signal indicative of the detected period of time to the microcomputer. Based on the signal from the failure detectors, the microcomputer detects a failure when the detected period of time exceeds a predetermined period of time.

Abstract: A motor control for a treadmill has an improved, inexpensive, and simple set of power supplies, derived from the bus voltages of the DC busses with simple voltage dividers, to supply operational amplifiers connected to the positive DC voltage bus with a dual voltage supply and a common or neutral, and to provide a single voltage power supply connected to the negative bus for the driving circuitry of a motor energization switching controlling element. The dual power supply for the operational amplifiers comprises a voltage divider containing two, series connected zener diodes in series with a resistor. The one of the series connected zener diodes is connected to the positive DC voltage bus, and the resistor is connected to the negative DC voltage bus. A common connection between the two zener diodes becomes the neutral or common voltage for the operational amplifiers, and the zener diode voltages become the positive and negative supply voltages for the amplifiers.

Abstract: A pulse width modulator comprises: a reload register (8) which stores data D1 set as an initial value of data D and loads to a waveform timer (3), every time one waveform cycle is counted; a comparing circuit (10) which compares the data D1 and data D2 when the data D1 is changed to the data D2; and an incrementer/decrementer (9) which functions as an increment when the data D2 is larger than the data D1 as the comparing result, and as an decrementer when smaller, and every time the one waveform cycle is counted by a cyclic timer (7), increments or decrements the data D1 held in the waveform timer (3); and changes the ratio of an "H" level period and an "L" level period of an output waveform relatively slowly, against the rate of change (from D1 to D2) of a set value D of a timer register (2) for setting the "H" level period and the "L" level period of a pulse width modulation waveform.

Abstract: An impact load controller (28) compensates for the speed drop of a drive motor (12), which speed drop is caused by a load disturbance applied to the drive motor (12). A change in the dynamics of a speed controller (30, 34) in a speed regulator system for a stand in a tandem rolling mill is initiated by detecting a speed error (WE) which is greater than a predetermined speed error value and is removed after the speed error has been reduced to a predetermined value. The controller (28) is a pure rate controller whose input is converted into a rate change in speed error, which is multiplied by a gain factor. The resultant gain value product is initially increased by a predetermined factor to provide a high input signal to the (PI) speed controller (34) of a multi-loop speed regulator system for the drive motor (12), and to precharge a low pass filter.

Abstract: A control for energizing a DC motor to provide improved speed regulation to the motor under transient conditions. The control includes a regulating circuit having an output signal controlling the armature voltage applied to the motor. An input speed reference signal corresponding to the desired speed of said motor is provided to the regulating circuit. An input armature voltage feedback signal is also provided to the regulating circuit to produce an error signal for operating said regulating circuit to establish the armature voltage, and hence the speed of said motor. The armature current of the motor is sensed and a signal corresponding to the voltage drop resulting from the inductance of the armature circuit provided to the regulating circuit for altering the output of the regulating circuit in a manner tending to establish the speed of said motor at that established by said speed reference signal. An IR compensating circuit provides an IR compensating signal to the regulating circuit.

Abstract: A method of cyclically accelerating an electric motor for example for use during an agitation cycle in a laundry machine. A desired speed, direction of rotation and acceleration time is set and power is applied to the motor in a series of incremental steps, each successive step corresponding to an increase in the level of power applied during the previous step. The steps are initially estimated to be sufficient to enable sufficient energy to be supplied to the motor for it to reach the desired speed in the acceleration time. The speed of the motor is monitored and the steps of accelerating the motor are repeated with the series of incremental steps adjusted to adjust the supply of energy to the motor dependant on the speed reached in the acceleration time of the previous cycle.

Abstract: Method of controlling electric valves of a converter using a universal algorithm for generating pilot signals (11) for multistage and multiphase line- and self-commutated converters (13, 14) is specified, by means of which it is possible to control different types of converters. The control algorithm can be realized as hardware or software. The invention is particularly suitable for multisystem locomotives. It is possible to change over to another feed system of the locomotive by a simple reprograming of a modulator (9) of a pilot signal generator (10). The modulator (9) and a pulse generator (8) receive modulator control signals (7) or pulse generator control signals (6) from a setter (5), together with which they form the pilot signal generator (10).

Abstract: A system and method for controlling the speed of a motor operating in an extremely low speed range and having a rotary pulse encoder which outputs a pulse whenever a rotation axle of the motor has rotated through a predetermined angle. The extremely low speed range is defined such that its pulse interval of the output pulses is longer than a speed control period of the system are disclosed, load torque estimated value observer is provided. The least order disturbance observer includes a first calculating block which calculates an estimated value of the motor speed n.sub.M ' (j) of a motor model on the basis of a torque command and a load torque estimated value: a second calculating block which calculates an average value of the motor speed at each pulse interval n.sub.M ' (j).

Abstract: The speed of the suction motor in a vacuum cleaner can automatically be controlled according to the size and amount of the sucked dust on floors, carpets and the like to be cleaned. The amount of dust being sucked is detected, pulse signals corresponding to the detected amount of the sucked dust are output, a duty cycle of the output pulses is calculated for a predetermined period of time, the amount of dust according to the calculated duty cycle is calculated and a firing angle of the suction motor is controlled based on the calculated values of the amount of dust. Power consumption and noise in the vacuum cleaner are reduced and the user can exactly plan his or her cleaning schedule in consideration of the amount of dust. Further, the current speed of the suction motor is displayed on the display, thereby enabling the user to exactly recognize the current amount of dust.

Abstract: For operating a plurality of mechanisms with a single motor, a motor control device is provided which is capable of stably operating one of the mechanisms while reducing influence of load imparted on the motor and attributed by an operation of remaining one of the mechanisms. A CPU suitably controls or selects electrical current level provisionally ranked and stored in a ROM to a printing motor which drives a print hammer for obtaining predetermined velocity of the hammer. If the print hammer reaches its decelerating position, the CPU determines offset electrical current level and current applying period to be applied to the printing motor on a basis of the rank of the electrical current at that phase.

Abstract: A fire-fighting system in which a liquid chemical foamant is introduced into the water stream in varying amounts so as to maintain a predetermined percentage mixture irrespective of variations in the water flow includes a motor-driven pump where the motor is controlled over a first speed range by pulse width modulating the drive to the motor and over a second speed range, producing intermittent motion, by burst width modulating the drive signal when it is operating at its minimum pulse width modulated duty cycle. Using this technique the range of available motor speeds is extended well beyond that which can be achieved using pulse width modulation of the motor drive signal alone.

Abstract: A clock signal is applied to an UP/DOWN counter, which counts up the clock signal from zero up to a predetermined value and then counts down from the predetermined value to zero, and thereby a triangular wave signal representing counted value is output therefrom; three threshold values which are different each other are selected between zero and the predetermined value in advance, and they are set in three digital comparators, respectively; in each digital comparator, the threshold value is compared with a level of the triangular wave signal, and when the threshold value is larger than the level of the triangular wave signal, a high level signal is output from each digital comparator, the high level signal is delayed by a predetermined delay time and three-phase PWM signal is generated.

Abstract: A driving circuit for a motor such as a spindle motor used in a floppy disc driver, a hard disc driver, etc. includes an output stage driver which supplies a driving current to a motor to rotate at a constant rotation speed. The driving current is supplied to the motor in an off-and-on way in which the power loss is small at a starting state, while the driving current is supplied thereto in changing linearly in which there generates little noise at a stationary state.

Abstract: The present invention pertains to a multiphase pulse width modulator which allows for continuous conduction of current through each winding of a multiphase motor at all times of the motor's operation. In a preferred embodiment, the multiphase pulse width modulator is for an N-phase motor, where N.gtoreq.3. The multiphase pulse width modulator is comprised of a clock for producing a switching frequency. The modulator is also comprised of means for providing N phase displaced signals to the respective N phases of the N phase motor such that the signals allow for continuous conduction of current through each winding in the motor at all times of the motor's operation. The providing means is connected to the clock for receiving the switching frequency, and connected to the N phases of the N phase motor to provide the N signals to the respective N phases of the N phase motor.

Abstract: A flexible disk drive device includes an adjusting circuit which sets termination timing of outputting of an index signal in response to the rotating speed of a motor by adjusting charge or discharge time constant of a capacitor; a reference voltage generating circuit which includes a plurality of resistors connected in series between the power source line and the ground line and generates the reference voltage at one of the nodes of the resistor chain; and a reference voltage switching circuit which switches the reference voltage to another reference voltage upon receipt of a speed selection signal which represents a different rotating speed from a predetermined rotating speed, wherein the other reference voltage is so set that the pulse width of the index signal corresponds to a predetermined rotating angle of the motor.

Abstract: The flow of power through a field effect transistor to a DC motor is controlled by the output of a frequency modulator having a low frequency pulsed signal applied to one input thereof and a high frequency pulsed signal applied to a second input thereof. The pulse width of each "on" pulse of the low frequency pulsed signal is varied in response to a signal representing a desired motor speed. Optionally, the pulse width of each "on" pulse of the high frequency pulsed signal can also be varied in response to the signal representing the desired motor speed. A filter circuit can be employed to prevent rapid changes in the pulse width of the low frequency pulsed signal. Similarly, a filter circuit can be used to avoid rapid changes in the pulse width of the high frequency pulsed signal. A freewheeling diode can be used to minimize inverse voltage spikes across the motor.