Abstract: Various embodiments of the teachings herein include a rectifier. The rectifier may include: a rectifier circuit formed with current valves with microelectromechanical systems (MEMS) switches; and a switching controller driving the MEMS switches to switch and open. The switching controller opens the MEMS switches when a voltage feeding the rectifier falls below a minimum distance from a zero voltage.

Abstract: Modulated pulse control of electric machines to deliver a desired output in a more energy efficient manner by either (a) operating the electric machine in a continuous mode when a requested torque demand is greater than the peak efficiency torque of the electric machine or (b) in a pulsed modulation mode when the requested torque demand is less than the peak efficiency torque of the electric machine. When operating in the pulsed modulation mode, the inverter may be deactivated to further improve the system efficiency when field weakening is not required to mitigate or eliminate generation of a retarding torque in situations when Back Electromagnetic Force (BEMF) exceeds a supply voltage for the inverter of the machine.

Abstract: A power conversion apparatus includes: matrix converter circuitry configured to perform bidirectional power conversion between a primary side and a secondary side; and control circuitry configured to: select a first control mode in response to determining that a command-primary frequency difference between a command frequency and a primary side frequency of the matrix converter circuitry is above a predetermined threshold, wherein the first control mode includes causing a secondary side frequency of the matrix converter circuitry to follow the command frequency; select a second control mode in response to determining that the command-primary frequency difference is below the threshold, wherein the second control mode includes maintaining a primary-secondary phase difference between a secondary side phase and a primary side phase of the matrix converter circuitry within a predetermined target range; and control the matrix converter circuitry in accordance with a selection of the first control mode or the secon

Abstract: This power conversion device includes a power module that has a plurality of power devices, and a circuit board that is connected to the power module, in which the circuit board has a drive circuit arrangement area in which a plurality of drive circuits for driving the plurality of power devices are disposed and a control circuit arrangement area in which a control circuit for controlling the drive circuit is disposed, and two drive circuit arrangement areas are provided with the control circuit arrangement area interposed therebetween.

Abstract: This motor control devices provided with: a motor control unit which generates a command value on the basis of a motor drive command acquired from a PLC over a communication line; a drive unit which supplies motor drive voltage according to the command value; an interruption unit which interrupts transmission of the drive signal to the motor; a safety input unit which receives an emergency stop input operation over a control signal line; a reset input unit which receives a reset input operation; a determination unit which determines whether or not safety is maintained on the basis of input to the safety input unit; and a safety control unit which, when the safety input unit receives an emergency stop input operation, performs interruption processing of the drive signal through the interruption unit, and when the reset input unit receives a reset input operation, performs restart processing if safety is maintained.

Abstract: An irrigation system that includes multiple interconnected spans that are supported by multiple tower structures. Each intermediate tower structure and end tower structure may include a dual-controller drive assembly that may include both a fixed-speed drive controller controlling the speed of movement of the dual-controller drive assembly when the fixed-speed drive controller is selected and a variable-speed drive controller controlling the speed of movement of the dual-controller drive assembly when the variable-speed drive controller is selected, and one or more selector switches configured to either manually, based on manual operator input, or automatically, based on automatic sensor input, select between the fixed-speed drive controller and the variable-speed drive controller.

Abstract: An anti-rebounding control apparatus is provided, which includes an anti-rebounding controller outputting a first command for setting a torque limit value to “0” if an electric motor speed value is equal to or smaller than an upper threshold value and equal to or larger than a lower threshold value in the case where a speed command value of “0” is input and outputting a second command for setting the torque limit value to a maximum value if the electric motor speed value is smaller than the lower threshold value, a torque regulator setting the torque limit value to “0” when the first command is input and setting the torque limit value to the maximum value when the second command is input, and an electric motor inverter intercepting a power that is supplied to an electric motor if the torque limit value is set to “0” and re-supplying the power to the electric motor if the torque limit value is set to the maximum value.

Abstract: A system for driving an electric machine is provided. The system includes a power converter coupled to an input source and the electric machine. The power converter includes a leg that includes a first and second string. The first string includes plurality of controllable semiconductor switches, a first and second connecting node. The first string is operatively coupled across a first and second bus. The second string is operatively coupled to the first string via the first and second connecting node. The second string comprises plurality of switching modules. The switching modules include fully controllable semiconductor switches and energy storage devices. The system further includes a system controller configured to provide activation commands to the controllable semiconductor switches and the switching modules such that energy stored in the energy storage device is provided to the electric machine when the machine is switched on for operation.

Abstract: An electric power converter is provided with a plurality of power-conversion elements; a first control circuit that outputs a first control signal; an electricity storage circuit; a second control circuit that outputs a second control signal when the direct-current power source that supplies electrical power to the first control circuit is not normal; and a drive circuit that outputs drive signals for driving the plurality of power-conversion elements. Each of the power-conversion elements is either a power-conversion element of the upper arm connected to the high-voltage side or a conversion element of the lower arm connected to the low-voltage side. In cases when the voltage of the electricity storage circuit is at a higher predetermined first voltage value, the second control circuit outputs a second control signal so that all the power-conversion elements of the upper arm or the lower arm are turned on and the others are turned off.

Abstract: Method of controlling a motor vehicle windscreen wiper motor, powered and controlled by pulse width modulation (PWM) with duty ratio (T) of determined value, in which the instantaneous fundamental period of the modulated pulses is switched successively between at least two discrete period values (T1, T2), the duty ratio (T) of the pulses (PWM) being substantially established at a determined value for at least one determined duration (Tc) of switching of the modulated pulses. Application to the reduction of the EMC noise level in the radio frequency bands to be protected.

Abstract: In hybrid construction machine employing a hydraulic motor and an electric motor for the driving of the swing structure, satisfactory operability of a combined operation of the swing structure and other actuators is secured irrespective of the operating status of the electric motor. A control device of the hybrid construction machine executes control selected from: hydraulic/electric complex swing control for driving the swing structure by total torque of the electric motor and the hydraulic motor when a swing operating lever device is operated; and hydraulic solo swing control for driving the swing structure by the torque of the hydraulic motor alone when the swing operating lever device is operated.

Abstract: The invention relates to a method of control implemented in a variable speed drive for controlling the deceleration of an electric motor (M) in the case of electrical power outage. The method of control comprises: a step of determining the Joule-effect losses to be applied to the electric motor (M) and to the variable speed drive according to a deceleration ramp to be applied to the electric motor (M) during an electrical power outage, a step of determining the flux reference (?ref) as a function of the said Joule-effect losses to be applied to the electric motor (M) and to the variable speed drive.

Abstract: A high performance electric pulse motor without a collector, with an electronic control circuit, capable of performing either with direct current or with alternating current. The motor includes a magnetic circuit at its stator including a pair of stator polar pieces, an induction coil at each polar piece, and a rotor between the polar pieces. The rotor has at least a pair of radial extensions in opposition for each pair of polar pieces in the stator and, attached to the rotor's axis, means opaque to light having a window allowing free passage of light. The motor further includes a permanent light source and a photo resistor.

Abstract: A circuit for speed monitoring of an electric motor comprises a circuit for generating a time-frame signal, a circuit for receiving a first signal from a chopper driver circuit designed to drive the electric motor, a circuit for detecting chopper pulses in the first signal, a pulse counter, and a circuit for at least one of outputting and evaluating a state of the pulse counter, after the inactive state of the time-frame has been indicated. The time-frame signal indicates when a time-frame of predefined length changes from an inactive state to an active state and indicates when the time-frame changes back from the active state to the inactive state. The pulse counter is designed to count the detected chopper pulses while the active state is indicated by the circuit for generating the time-frame signal.

Abstract: A matrix converter includes: a power conversion unit provided between an AC power supply and a rotational machine; and a controller for performing power conversion control therebetween by controlling the power conversion unit. The power conversion unit includes multiple bidirectional switches each of which has at least one first directional switching element and at least one second directional switching element. Further, the controller includes a first drive control unit performing the power conversion by simultaneously turning on both of the first directional switching element and the second directional switching element, and a second drive control unit performing the power conversion by turning on one of the first directional switching element and the second directional switching element.

Abstract: A variable speed electric motor controller includes a rotating cylinder having a variable amount of conductor material and a variable amount of insulator material along its length such that one side is mostly insulator and the other side is mostly conductor. An electrical connection, such as a brush, can contact the rotating cylinder and be moved therealong. A stationary electrical connector/brush can be permanently electrically connected to the conductor material. The flow of electricity from the movable brush to the stationary brush can be controlled by the speed of rotation of the shaft and the position of the movable brush therealong. The output can provide variable power to a load, such as an electric motor.

Abstract: A motor drive system includes a power sub-assembly that comprises power electronic components and driver circuitry for controlling gate drive signals to the power electronic components. A control sub-assembly is removably mounted to the power sub-assembly and comprises control circuitry for implementing a motor control routine for control of an electric motor. In operation, all control signals originate in the control-subassembly, and are transmitted via mating connectors to the power sub-assembly for driving the motor.

Abstract: A motor control device includes an H-bridge circuit for controlling on/off of a current fed to a motor, a drive circuit for driving the H-bridge circuit, a drive command signal generator for generating a drive command signal including a pulse signal having a predetermined drive frequency for sending a command to drive the motor, a current detection circuit that includes a current detection resistor and a comparator connected in series with the motor and outputs a comparison output signal based on comparison between a current detection signal of a motor current and a target value signal, a latch circuit for holding a current detection result based on an ON signal of the drive command signal and the comparison output signal, and a gate circuit for driving the drive circuit based on the ON signal of the drive command signal and a latch output signal from the latch circuit.

Abstract: An anti-rebounding control apparatus is provided, which includes an anti-rebounding controller outputting a first command for setting a torque limit value to “0” if an electric motor speed value is equal to or smaller than an upper threshold value and equal to or larger than a lower threshold value in the case where a speed command value of “0” is input and outputting a second command for setting the torque limit value to a maximum value if the electric motor speed value is smaller than the lower threshold value, a torque regulator setting the torque limit value to “0” when the first command is input and setting the torque limit value to the maximum value when the second command is input, and an electric motor inverter intercepting a power that is supplied to an electric motor if the torque limit value is set to “0” and re-supplying the power to the electric motor if the torque limit value is set to the maximum value.

Abstract: An electric power converter is provided with a plurality of power-conversion elements; a first control circuit that outputs a first control signal; an electricity storage circuit; a second control circuit that outputs a second control signal when the direct-current power source that supplies electrical power to the first control circuit is not normal; and a drive circuit that outputs drive signals for driving the plurality of power-conversion elements. Each of the power-conversion elements is either a power-conversion element of the upper arm connected to the high-voltage side or a conversion element of the lower arm connected to the low-voltage side. In cases when the voltage of the electricity storage circuit is at a higher predetermined first voltage value, the second control circuit outputs a second control signal so that all the power-conversion elements of the upper arm or the lower arm are turned on and the others are turned off.

Abstract: A rotary breaker that interrupts a transmission of a driving force from a motor to a drive mechanism unit is provided between the motor having a permanent magnet incorporated therein and the drive mechanism unit of an electric vehicle. A second controller controls the rotary breaker based on operation states of a power converting unit that has a power converter that drives the motor by converting a direct-current voltage or an alternate-current voltage into an alternate-current voltage with an arbitrary frequency and a first controller that controls the power converter, operation states of the motor and the rotary breaker, and an operation state of the second controller itself.

Abstract: A method is provided for controlling a position of an electric dc brush motor (22, 24) including the steps of supplying drive current (104) to drive the electric motor and calculating (70, 108) a coast constant for the motor. Current through the motor is monitored (80) and motor speed (66) is determined in response to monitored motor current. Electrical current to the motor is interrupted (50) in response to the calculated coast constant (70, 106) and motor speed when it is desired to stop the electric motor so that a brush of the motor will come to rest at a location on a commutator segment of the motor (22, 24).

Abstract: The invention relates to an electrical drive having a motor with a rotor and a stationary stator, which has a coil arrangement, and having a motor controller for controlling the motor, with the motor controller being configured to pass current through the coil arrangement in order to produce an excitation field, with the coil arrangement having a plurality of coil winding sections, and with each coil winding section having a plurality of coil sections, wherein the polarity of at least one coil section of the plurality of coil sections of each coil winding section can be selectively reversed with respect to the other coil sections of the coil winding section. The drive is particularly suitable for use for an electrical tool.

Abstract: Disclosed herein is a Pulse Width Modulation (PWM) controller. The PWM controller includes a plurality of Field Effect Transistors (FETs) and an FET driver. A comparator compares a current flowing through the FETs with an overcurrent reference value, and microcomputer controls a motor and a circuit protection function, and turns off the FET driver when the current flowing through the FETs is greater than the overcurrent reference value as a result of comparison by the comparator.

Abstract: A method of starting and apparatus for starting a multiphase electrical machine is disclosed. The aim is to reduce oscillatory pulsation in torque generated by the motor and inrush current that occurs shortly after start-up. The starting method comprises the steps of first connecting at least one, but less than all, of a plurality of windings to a respective phase-shifted supply voltage at a controlled point in the supply phase. Then, after a controlled delay following the first connection, connecting the or each remaining winding of the machine a respective phase-shifted supply voltage. The invention has particular application to multiphase (most usually, 3-phase) motors. However, it can also be applied to other electrical machines, such as generators and transformers. The method can be performed at initial start-up or, in the case of application to a motor, at Y-delta switchover.

Abstract: A hybrid ECU executes a program including the steps of: setting a fan driving level F for a cooling fan, as based on a high voltage battery's temperature TB, SOC and input and output currents, and a vehicular cabin's internal temperature and background noise; detecting from a signal transmitted from a voltage sensor the voltage of an auxiliary battery serving as a power supply for the cooling fan; and setting a duty command value for the cooling fan from fan driving level F and the auxiliary battery's voltage so that the duty command value is smaller as a voltage of the auxiliary battery is higher.

Abstract: A switching system includes a plurality of diodes forming a diode bridge, and a micro-mechanical system (MEMS) switch array closely coupled to the plurality of diodes. The MEMS switch array is electrically connected in an (M×N) array. The (M×N) array includes a first MEMS switch leg electrically connected in parallel with a second MEMS switch leg. The first MEMS switch leg includes a first plurality of MEMS dies electrically connected in series, and the second MEMS switch leg includes a second plurality of MEMS dies electrically connected in series.

Abstract: An electric power tool is provided that includes a motor as a driving source, a first operation switch, a first semiconductor switch, and a second semiconductor switch. The first operation switch is operated by a user to be turned ON/OFF. The first semiconductor switch, provided on a current path from the power source to the motor, includes at least one semiconductor switching device. When the first operation switch is OFF, the first semiconductor switch is turned OFF to interrupt the current path. When the first operation switch is ON, the first semiconductor switch is turned ON to close the current path. The second semiconductor switch is provided on the current path in series with the first semiconductor switch and includes at least one semiconductor switching device. The second semiconductor switch closes/interrupts the current path by being turned ON/OFF in accordance with an input control signal.

Abstract: An electric machine system includes an electric motor. The electric motor includes a stator having a plurality of windings that define a number of phases. A plurality of switch members are operatively coupled to the plurality of windings. The plurality of switch members are no more than one less than three times the number of phases. A controller is operatively coupled to the plurality of switch members. The controller selectively changes a state of the plurality of switch members to establish one of a first electrical connection configuration of the plurality of windings and a second electrical connection configuration of the plurality of windings.

Abstract: A rotary breaker that interrupts a transmission of a driving force from a motor to a drive mechanism unit is provided between the motor having a permanent magnet incorporated therein and the drive mechanism unit of an electric vehicle. A second controller controls the rotary breaker based on operation states of a power converting unit that has a power converter that drives the motor by converting a direct-current voltage or an alternate-current voltage into an alternate-current voltage with an arbitrary frequency and a first controller that controls the power converter, operation states of the motor and the rotary breaker, and an operation state of the second controller itself.

Abstract: In various embodiments, the present disclosure provides a speed control system for a motor that includes a fixed speed control portion and a variable speed control portion. The fixed speed control portion is operable to control a speed of a motor in a fixed speed mode wherein the motor is operated at a preselected fixed speed below a predetermined fixed speed mode threshold speed. The variable speed control portion is operable to control the motor in a variable speed mode wherein the motor is operated such that a speed of the motor can be selectively varied within a range between the fixed speed mode threshold speed and a maximum motor speed. The system additionally includes a switching device structured and operable to selectively switch the speed control system between the fixed speed mode and the variable speed mode.

Abstract: A method is provided for controlling a position of an electric dc brush motor (22, 24) including the steps of supplying drive current (104) to drive the electric motor and calculating (70, 108) a coast constant for the motor. Current through the motor is monitored (80) and motor speed (66) is determined in response to monitored motor current. Electrical current to the motor is interrupted (50) in response to the calculated coast constant (70, 106) and motor speed when it is desired to stop the electric motor so that a brush of the motor will come to rest at a location on a commutator segment of the motor (22, 24).

Abstract: An electric motor drive device has an inverter adjusting the voltage applied to an AC electric motor so as to drive the AC electric motor, a capacitor which is charged by a current supplied from a DC power supply supplying DC voltage between a neutral point at which a plurality of coils of the AC electric motor are connected and a positive rail or negative rail of an inverter and passing through the inverter, and a control circuit controlling the inverter so that the AC electric motor turns at a designated speed. Further, the control circuit selectively uses field weakening control and voltage boosting control for control of the inverter according to the conditions of the induced voltage generated at the AC electric motor, DC power supply, and voltage of the capacitor.

Abstract: An inverter for driving a motor includes a plurality of power semiconductor devices. The plurality of power semiconductor devices include a resistance electrically connected between a collector and an emitter of an IGBT element. Each of the power semiconductor devices forms any one of a U-phase arm, a V-phase arm and a W-phase arm of the inverter. As a result, a discharge resistance is built in the inverter, and therefore, it is not required to prepare the discharge resistance separately. Thus, the number of components required for a motor drive apparatus can be decreased and the number of operation steps can be reduced.

Abstract: An exemplary fan driving system includes a driving device and a MOSFET group. The driving device includes a first adjustable resistor connected between its first voltage signal input terminal and ground, and a second adjustable resistor connected between its second voltage signal input terminal and ground. The MOSFET group includes two N-type MOSFETs and two P-type MOSFETs. The first terminal of the fan is connected to an anode of D1 and a cathode of D3. The second terminal of the fan is connected to an anode of D2 and a cathode of D4. Cathodes of the D1 and D2 are configured to connect a supply voltage. Anodes of the D3 and D4 both are grounded. The fan driving system can effectively discharge off the residual current in the coil of the fan at the moment of the MOSFET group being switched off.

Abstract: A fan motor is controlled via a switching circuit from the moment when a cooling fan control routine is started until the moment when the rotational speed of the fan motor reaches a control-switching speed so that the higher the detected auxiliary battery voltage is when the cooling fan control is started, the lower the command duty ratio that is set. Accordingly, it is possible to activate the fan motor more reliably and to avoid generating excessive operating noise by the cooling fan when the fan motor is activated.

Abstract: A solid state relay has independent charge pumps isolating each gate of a full bridge to achieve faster and proper gate turn on. The low side MOSFETs of the bridge are the current sensing device reducing loss and allowing a device controlled by the relay to achieve peak performance. Dynamic braking is achieved by the two low side MOSFETs being fully conducted and applying a load across the DC motor. Addition of a microprocessor to the device provides undervoltage sensing, current vs time readings, motor stall sensing, and motor temperature sensing. Motor temperature is detected by checking impedance of the motor at microsecond pulses to see if the motor is getting hot.

Abstract: A robot control system including a servo amplifier supplying power to a robot, a processor controlling the operation of the robot, and a servo power connection/cutoff circuit connected to the same, issuing excitation/nonexcitation commands to a charging relay and a main circuit connection electromagnetic contactor provided in the circuit from the processor, monitoring the opened/closed states of the contacts of the charging relay and main circuit connection electromagnetic contactor by the processor, and detecting if their contacts open and close as instructed by the processor to thereby check if the power connection/cutoff circuit has a fault. Due to this, it is possible to provide a robot control system which detects faults of the power connection/cutoff circuit and which is inexpensive and high in safety.

Abstract: An exemplary fan driving system includes a driving device and a MOSFET group. The driving device includes a first adjustable resistor connected between its first voltage signal input terminal and ground, and a second adjustable resistor connected between its second voltage signal input terminal and ground. The MOSFET group includes two N-type MOSFETs and two P-type MOSFETs. The first terminal of the fan is connected to an anode of D1 and a cathode of D3. The second terminal of the fan is connected to an anode of D2 and a cathode of D4. Cathodes of the D1 and D2 are configured to connect a supply voltage. Anodes of the D3 and D4 both are grounded. The fan driving system can effectively discharge off the residual current in the coil of the fan at the moment of the MOSFET group being switched off.

Abstract: A control circuit of a sensorless motor includes a first coil, a second coil, a first switch circuit, a second switch circuit and an auxiliary switch circuit. The first switch circuit is electrically connected to the first coil and controls a direction of a current flowing through the first coil. The second switch circuit is electrically connected to the second coil and controls a direction of a current flowing through the second coil. The auxiliary switch circuit is electrically connected to and between the first coil and the second coil and controls the directions of the currents flowing through the first coil and the second coil by cooperating with the first switch circuit and the second switch circuit. A control method of a sensorless motor is also disclosed.

Abstract: Disclosed herein relates to a dynamoelectric machine conductor. The conductor comprising, a bus including a central portion, a first connectable site of the central portion connectable with a first conductor and a first arm having a second electrically connectable site connectable with a second conductor. A first fused portion of the first arm located between the first connectable site and the second connectable site, the first fused portion being electrically interruptible to open a circuit between the first connectable site and the second connectable site. A second arm having a third connectable site connectable with a third conductor, and a second fused portion of the second arm located between the first connectable site and the third connectable site. The second fused portion being electrically interruptible to open a circuit between the first connectable site and the third connectable site.

Abstract: A variable reluctance electric power system which comprises an alternator and a motor having a rotor with longitudinal lobes and no windings, commutators, slip rings, magnets, or laminations. The alternator and the motor have stators which have conventional windings and laminations and a rotor which is polarized using a static field winding which surrounds but does not touch the rotor. The alternator and the motor may be coupled with current from the alternator driving the motor and solid state power devices controlling the frequency of the current to insure that the current from the alternator is always synchronized with the motor rotor.

Abstract: A retarded electric motor designed as a series motor or an asynchronous motor having a squirrel cage rotor. A valve is provided for switching between motor operation and braking operation. During motor operation the motor is operated in a known configuration as series motor or as asynchronous motor. If configured as a series motor, the valve (S1, S2, S3) allows to bypass the armature and to operate the motor as an externally excited direct current generator when switching into braking operation. If configured as an asynchronous motor, a switch is utilized to disconnect at least two field windings from mains. A valve is utilized to excite the motor externally from mains with a pulsating direct current during braking.

Abstract: A dual current-limiting circuit for a dc brushless motor includes an over-current detective circuit, an operation detective circuit, and a current-limiting circuit. The over-current detective circuit produces a voltage signal used to determine whether an over-current has been input to the motor. The operation detective circuit also produces a voltage signal used to determine whether the motor is being operated in a normal manner. The current-limiting circuit decides to turn on a first switch of a first current-limiting circuit and to subsequently turn on a second switch of a second current-limiting circuit depending upon the two voltage signals. The current-limiting circuit is capable of suppressing current passing through a coil at a low voltage level, which is inadequate to damage a driver circuit and still adequate to restart the motor if an abnormal input current is eliminated.

Abstract: A method and apparatus for achieving constant air flow rate economically utilizes an induction blower motor with control settings determining the motor excitation voltage. A memory stores, for a variety of motor speeds, a graph of the speeds plotted against a proportionality constant of flow rate to fan speed for the selected motor system on one axis and motor control settings on the other axis. The only monitoring necessary to achieve the constant flow rate is thus the sensing of fan rotational speed. The measured fan speed is compared against the proportionality constant needed for the selected constant air flow rate and a motor excitation voltage is derived to achieve that proportionality constant. When the system load changes significantly, thereby causing significant fan speed change, a cascaded control loop is used whereby the speed changed induced by each control voltage adjustment is monitored until the desired constant flow rate is again attained at the new load level.

Abstract: A stop control circuit is configured from a hardware circuit that operates independently from a CPU. When a comparison circuit outputs a matching signal, then the stop control circuit starts processes for stopping a DC motor, regardless of the processing condition of the CPU. Accordingly, operations for stopping the DC motor can be executed at a stable timing so that the DC motor can be stopped at fixed positions. A stop detection circuit detects whether the print head has made an unscheduled stop for some reason or the other, and outputs an interrupt request signal to the CPU, when an amount that the print head is controlled to move has exceeded 20 H even though the actual amount that the print head has moved is still less than 5 H. Accordingly, the CPU need perform predetermined processes for the unscheduled stops only upon receiving the interrupt request from the stop detection circuit. Therefore, there is no need for the CPU to constantly check whether or not the print head has made an abnormal stop.

Abstract: A circuit for driving a three-phase brushless DC motor (301) includes a neutral point feedback circuit (201) which operates a three-phase output circuit (202) so that a neutral point potential (V.sub.C) of the motor (301) is maintained at a predetermined potential, and a neutral point potential comparison circuit (500) which determines whether or not the neutral point potential (V.sub.C) is between reference potentials (V.sub.ref1, V.sub.ref2). If the neutral point potential (V.sub.C) is not between the reference potentials (V.sub.ref1, V.sub.ref2), a switch shutoff signal (SC) is activated to turn off a switch (106), so that a current (I.sub.C) is not provided to the neutral point feedback circuit (201). Accordingly, the neutral point feedback circuit (201) stops flowing currents (I.sub.A, I.sub.B) to the three-phase output circuit (202) which in turn stops driving the motor (301). The circuit for driving the motor (301) is prevented from being broken down if a short circuit occurs in the motor (301).

Abstract: Between one end of a motor coil and the ground, a drive transistor is connected. When the drive transistor is turned off, and in particular at the moment when a current flowing through the motor coil drops to zero, a back electromotive force is induced at said one end of the motor coil. The back electromotive force is clamped by a pnp-type transistor with its base supplied with a constant voltage and its emitter connected to said one end of the motor coil.

Abstract: A Direct Current drive system with a multiplicity of applications including that of powering electric vehicles. The system contains a hybrid electric motor formed by a unique synchronous arrangement of two electrical motors, a primary and a secondary. The single input of Direct Current to the primary motor enables the secondary motor to operate on the Alternating Current generated in the primary motor, and in doing so captures the transformation of energy that takes place during the collapse of a magnetic field. This captured energy is then used to help drive the secondary motor, thus greatly increasing efficiency. A brake/alternator is included to provide a means of slowing/ stopping the motor while at the same time assisting in recharging the primary power source by sending current through a rectifier to the battery which powers the motor.

Abstract: A separately excited DC motor system is arranged to provide operation in a smooth, continuous electrical retarding mode. A series contactor connects the motor armature to a DC power source and is controlled so as to immediately open upon sensing of a need for electrical braking. Concurrently, power to the motor field is reversed so that no additional changes are required to brake to zero speed. Field current is modulated to control armature current so as to control braking effort. When speed falls below a value necessary to maintain armature voltage above battery voltage, the armature is cyclically short-circuited to boost armature current so that when the short-circuit is removed, the armature reactance forces current to continue for regeneration.