Abstract: A current detector (60) samples a motor current (MCRT_A) from a controlling sensor and a motor current (MCRT_B) from a monitoring sensor, and holds respective motor current maximum values (MCRT_Amax, MCRT_Bmax) at each prescribed operation cycle. An abnormality determiner (62a) detects that the motor current maximum value (MCRT_Amax) is in GND short-circuiting range and that the current difference between the maximum values exceeds a prescribed threshold value at each of successive operation cycles, to thereby determine an abnormality of the controlling sensor. Then, the abnormality determiner (62a) generates a detect signal (DET) specifying the current sensor abnormality and outputs it to a relay driver (64) and an alarm (66). Relay driver (64) receives the detect signal (DET) and generates a signal (SE) to turn off a system relay. The alarm (66) generates a signal (AL) and outputs it to display means arranged outside a power supply apparatus.

Abstract: A fan motor driving circuit controls an energized state of a fan motor by performing on and off control of a switching circuit connected to a coil of the fan motor of a driving object. A variable reference voltage circuit generates a voltage whose voltage level changes with time by charging or discharging a capacitor at the start of starting up the fan motor. A drive signal combining unit generates drive signals on the basis of the voltage when at least starting up, and performs on and off control of the switching circuit by the drive signals. An initialization circuit initializes the capacitor before starting up with a transition from off to on of a power supply voltage to be supplied to the fan motor driving circuit as a turning point.

Abstract: The invention provides an electric motor including a tubular insulator that insulates coils of each of U, V, and W phases that makes a rotor rotated by an electromagnetic force, and a stator core around which the coils are wound; and a plurality of busbars that are fixed to the insulator to relay feed of power to the coils that constitute each phase. Ring-shaped terminals directly connected to an external driving circuit board for controlling a driving current leading to each phase of the coils, without via separate connecting members, are integrally formed in the busbars, respectively.

Abstract: A current limiting DC motor starter employing a closed loop current measurement to provide precise current control that adapts to changing motor conditions, integrated with a solid state reversing motor starter. The motor starter further includes a calibrated overcurrent indication and a control system interface that reduces the likelihood that cable faults and other single failures will cause spurious actuation of the motor.

Abstract: An electric power-assist system for a manually operated vehicle, such as a bicycle, has a pedal with Hall sensors for producing a signal representing a rotational speed of the pedal, and an electric motor for power assisting the driving force of the bicycle. A speed counter, speed decision block, up/down counter, and comparator are provided so that the power assist by the electric motor increases or degreases, as the speed of the manual controlling device increases or decreases, respectively.

Abstract: A method and apparatus for driving a spindle motor using adaptive feedforward control. The method includes: detecting a temperature of a drive; calculating a feedforward value corresponding to the detected temperature; and generating a first control signal that is a drive current according to a calculated feedforward value and applying the generated first control signal to the spindle motor.

Abstract: A semiconductor integrated circuit device according to the present invention includes: a sample circuit in which through current to be monitored flows during switching between transistors; a non-overlap circuit for outputting an output signal for the switching in the sample circuit; a current detector for detecting the through current flowing during the switching; and a current comparator in which a reference current value with respect to the through current has been set and which compares a current value detected by the current detector with the reference current value and outputs a result of the comparison to the non-overlap circuit.

Abstract: The present invention relates to portable powered devices or tools for residential, commercial, or industrial applications, in which the power source may be carried on the back of the individual user, power is transferred via a flexible drive shaft, and the powered devices or tools may be quickly connected to or disconnected from the power source via a quick-connect power take-off and power take-on to allow the user to quickly, safely and ergonomically accomplish a variety of tasks, each requiring a different device or tool. Among residential, commercial, or industrial applications, the invention relates to power sources which are light-weight internal combustion engines or AC or DC powered electric motors and to portable powered tools for landscaping, maintenance and repair; such as, without limitation, string-trimmers, edge-trimmers, hedge cutters, brush saws, blowers, drills, buffers, grinders, sanders, drainer cleaners, or sump pumps.

Abstract: In a motor driving device where a motor having a winding wire with small inductance value is driven by a digital control means comprised of control means including a current command value calculating means, a current control means and a PWM control means whose sampling periods are different from each other, when discrete signals sampled by the respective control means are zero-order-held, a motor current includes a lot of higher harmonic waves due to a quantization error, thereby increasing a motor noise. When an n-th-order hold means is provided between the respective control means with different sampling periods, the quantization error can be reduced remarkably, and thus the higher harmonic wave components included in the motor current are reduced, thereby greatly reducing the motor noise.

Abstract: An object is to provide a driving device capable of smoothly shifting from a starting state to a sensor-less vector control, in a case where the device drives a motor by the sensor-less vector control, and the device includes a voltage detecting circuit which detects an induced electromotive voltage of the motor. A control circuit starts the motor by rectangular wave control. A magnetic pole position of a rotor is detected based on an induced electromotive voltage of one remaining phase of the motor detected by the voltage detecting circuit. The control circuit controls a main inverter circuit based on the detected magnetic pole position, and accelerates the motor by the rectangular wave control. In a case where a predetermined shift revolution speed is reached, the control circuit shifts to vector control by the sensor-less in which the magnetic pole position detected during the rectangular wave control is used as an initial value.

Abstract: A method of testing an electric motor that is adapted to provide a desired electric motor output torque to a vehicle powertrain system comprising an engine and the electric motor which are operatively and selectively coupled to a transmission. The method includes the steps of determining an initial motor speed of the electric motor, determining a motor torque command as a function of the initial motor speed, applying the motor torque command to the electric motor to produce an output torque from the electric motor, measuring a resultant motor speed of the electric motor and establishing a motor status as a function of the resultant motor speed. The method may be implemented as a computer control and diagnostic algorithm.

Abstract: A motor drive control device and motor startup method prevent startup noise and reduce startup time. At startup, a current to which a rotor does not react is passed through two phase coils of a polyphase DC motor in succession, and a voltage polarity induced in a non-conducting phase is detected. A first operation decodes the detected signal, and determines phase coils of the motor through which a current should pass to rotate the rotor and the energization direction. A second operation forms a control signal for passing a current according to the determination to drive the motor, detects a voltage peak induced in the non-conducting phase during the drive, and performs switching control of a conducting phase. In normal operation, the position of the rotor is detected based on a back EMF in each phase, and rotation control is performed.

Abstract: A controller and a constant measuring apparatus have a means for supplying a synthesized current, resulting from superimposing an AC current to a DC current, from an inverter and for changing the DC current component of the synthesized current continuously or discontinuously. Accordingly, the controller and constant measuring apparatus can measure inductances, which are electric constants of the AC motor, with high accuracy and can use the measured inductances for control.

Abstract: A brushless DC motor drive apparatus for driving a rotor includes a drive circuit rotating the rotor, a current shutdown and auto-restart circuit coupled to the drive circuit, and a DC voltage comparison circuit coupled to the current shutdown and auto-restart circuit. The current shutdown and auto-restart circuit detects blockage of the rotor via the DC voltage comparison circuit and shuts off the power to the drive circuit accordingly.

Abstract: The invention relates to a method and a circuit arrangement for monitoring the mode of operation of one or more load circuits, especially of a domestic appliance, which contains a controlled semiconductor switch, such as a triac, and an electric consumer. Said switches are supplied by at least one alternating voltage source that supplies an alternating voltage including positive and negative voltage half-waves. The invention is characterized in that the currents flowing through all controlled semiconductor switches (T1, T2) and the electric consumers (R1, R2) are guided through a common low-impedance precision resistor (Rm). The respective voltage drop occurring over the low-impedance precision resistor (Rm) is separately evaluated with respect to the amplitudes of the positive and negative voltage half-waves.

Abstract: At first, a plurality of detection modes are applied in sequence to a brushless DC motor, such that with respect to each of the detection modes a composite magnetic field generated by a motor current flowing through motor coils points in a different direction. Then, each of peak values of the motor currents generated by the detection modes is compared with respect to one another so as to select, from the plurality of detection modes, one detection mode which generates a largest one of the peak values of the motor currents. An initial position of a rotor is determined on a basis of a direction of a composite magnetic field generated by the detection mode which generates the largest one of the peak values of the motor currents. Based on the initial position of the rotor, the brushless DC motor is driven to start rotating.

Abstract: A control and motor arrangement in accordance with the present invention includes a motor configured to generate a locomotive force for propelling the model train. The control and motor arragement further includes a command control interface configured to receive commands from a command control unit wherein the commands correspond to a desired speed. The control and motor arrangement still further includes a plurality of detectors configured to detect speed information of the motor, and a process control arrangement configured to receive the speed information from the sensors. The process control arrangement is further configured and arranged to generate a plurality of motor control signals based on the speed information for controlling the speed of said motor. The control and motor arrangement yet still further includes a motor control arrangement configured to cause power to be applied to the motor at different times in response to the motor control signals.

Abstract: A control unit for a moveable barrier, such as a garage door, includes a microcontroller connected to a motor speed detector, motor current sensor or a sensor for determining forces exerted on or by the barrier. A user interface includes user actuatable switches for setting a first maximum force value to be exerted on or by the barrier when moving in one direction and the microcontroller automatically sets the value of a second maximum force to be exerted on or by the barrier when moving in the opposite direction. The second force value may be based on the force value set by the user or the second force value may be a preset value. Both force limits may be automatically set as a function of a maximum force exerted on said barrier during movement thereof, during a force learning operation.

Abstract: A rotary sensor that outputs two analog signals, such as one sine wave and one cosine wave and has multiple periods within one period of the electrical angle of a motor is employed. The motor is energized at each position for a specified length of time upon its startup by using multiple electrical angles corresponding to the multiple candidate absolute angles obtained from the rotary sensor signal as the initial position of the motor, and the electrical angle at which the motor acceleration becomes maximum is determined as the absolute angle. While the motor drive is in operation, on the other hand, the phase difference ?? between the phase of the motor at the counter electromotive voltage and the control phase is directly computed from the parameters of the motor, sensed current, voltage command and angle speed so as to correct the shifted position.

Abstract: A motor control arrangement includes a device connected to positive power such that device drives motor upon connecting to negative power. A switch connects to positive power upon actuation. A first transistor connects to switch via controller and connects between device and negative power. First transistor turns on causing device to connect to negative power upon switch actuation while controller is operational. A second transistor connects to switch and connects between device and negative power when controller is malfunctioned. Second transistor turns on causing device to connect to negative power upon switch actuation while controller is malfunctioned. A sensor connects to negative power upon contact with water. A third transistor connects to switch and sensor such that its collector-emitter path is connected in parallel to device.

Abstract: The arrangement as overload protection for the mains voltage (U) comprises an electric motor (1), a compression unit having a compressor (2), a mains voltage-monitoring unit (3), a device for reducing the load on the motor (1) and a control arrangement (4). The control arrangement (4) is connected to the mains voltage-monitoring unit (3) and to the device for reducing the load on the motor (1) such that the motor (1) is disconnected from the load as soon as the mains voltage (U) falls below a predetermined, first threshold value. The load on the motor (1) comes from the pressure difference between the inlet (E) and the outlet (A) of the compressor (2), which is driven by the motor (1).

Abstract: The invention proposes an electrically operated power steering controller for inputting a driving electric current offset value of higher accuracy and being able to make an offset correction of a driving electric current by using this driving electric current offset value of higher accuracy, and an adjusting method of this driving electric current offset. Therefore, an electric motor driving electric current measuring device of accuracy higher than that of an electric motor driving electric current detector assembled into a controller CNT is prepared separately from this electric motor driving electric current detector. The driving electric current offset value of high accuracy is outputted by this electric motor driving electric current measuring device. An input device for receiving the driving electric current offset value of high accuracy from the driving electric current measuring device is arranged in an offset correcting device or an offset signal generator within the controller.

Abstract: A system and method for measuring the electrical current used by an electrical device and controlled according to the Pulse Width Modulation (PWM) method, such as a DC motor, the system using a Field Effect Transistor (FET) coupled to the electrical device such that the voltage applied to the FET is measured to ascertain in part, the current usage of the electrical device.

Abstract: The invention relates to an electric driven tool device, especially an electric hand-held tool device, comprising an asynchronous electric motor (2) or a brush-less synchronous electric motor and a computer-controlled motor control device (8). The invention is characterized by a frequency converter (4) which can be controlled by the motor control device, whereby a motor (drive) voltage can be applied to the motor (2), and with a current detector (10) which co-operates with the motor control device (8) and detects the motor current. The motor control device (8) is embodied in such a manner that, in a first phase of the motor operation, the frequency of the motor current is maintained in a constant manner up to a limiting current I(grenz) and, in a second phase of the motor operation, at loads above the load at which the motor current reaches the limiting current I(grenz), the frequency of the motor current is lowered in such a manner that the motor current is maintained at a constant value.

Abstract: The invention concerns a starter for a line start electric motor having at least one main winding (4) and at least one start winding (12) and which start winding is connected in series with a run capacitor (14) with which a start capacitor (17) and a PTC-thermistor (19) are connected in parallel. In order to make a simply constructed starter for a line start electric motor the start capacitor (17) and the PTC-thermistor (19) are connected in series with a switch mechanism (20). The series connected circuit made up of the start capacitor (17), the PTC-thermistor (19) and the switch mechanism (20) is connected in parallel with the run capacitor (14).

Abstract: A control apparatus for a synchronous motor such as a switched reluctance motor, having a plurality of respectively separate stator windings, can operate the motor in either a normal mode or a low-torque mode by selectively supplying drive current to the stator windings. In the low-torque mode, alternate ones of the stator windings are driven in succession, thereby ensuring that electromagnetic forces will not be continually applied to the rotor of the motor along the same limited range of directions and so preventing unbalanced wear of the rotor shaft and bearings.

Abstract: A startup failure detection system provides an indication of motor startup failure based on a flux amplitude signal value. The flux amplitude signal is derived from motor flux estimations in combination with a rotor angle estimation. The flux amplitude signal value is compared to an upper and lower threshold value, and a startup failure is indicated if the flux amplitude signal value is outside the range determined by the upper and lower threshold value. The motor drive system can be set to attempt a restart when a motor drive startup failure is detected, with the retrial current, duration and the total number of retrials being user selectable.

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: In a sensorless motor driving device for driving a motor by controlling the energization of the coils of individual phases of the motor according to the result of detecting the position of the rotor of the motor without using an external sensor, before the motor is started, which phase to energize first when the motor is started is determined according to the result of detecting the position in which the rotor is at rest by exploiting the fact that the coils of the individual phases have varying apparent inductances according to the position in which the rotor is at rest. This circuit configuration permits the motor to be started always in the same rotation direction, and thus prevents reverse rotation of the motor.

Abstract: A vehicular generator-motor 1 is composed of a rotor, a stator having three phase armature winding 2, and a converter 4. The rotor is provided with a field winding 3 for magnetizing a plurality of magnetic pole pieces 14a, 15a, and permanent magnets 17 for magnetizing the magnetic pole pieces 14a, 15a together with the field winding 3. When the generator-motor 1 is operated as a motor, the converter 4 is operated as an inverter to restrain the armature current at the time of low speed rotation to the extent of the additional magnetic flux from the permanent magnets.

Abstract: A semiconductor integrated circuit device according to the present invention includes: a sample circuit in which through current to be monitored flows during switching between transistors; a non-overlap circuit for outputting an output signal for the switching in the sample circuit; a current detector for detecting the through current flowing during the switching; and a current comparator in which a reference current value with respect to the through current has been set and which compares a current value detected by the current detector with the reference current value and outputs a result of the comparison to the non-overlap circuit.

Abstract: A power-assisted steering system includes: two or more current detectors that detects current flowing to two or more phases of a motor and outputs detected current values; a correcting unit that corrects the detected current values output from the current detectors to compensate a difference in gain between the current detectors; and a motor driving driver that drives the motor based on a deviation between the target current value and corrected detected current values. When the same current flows to the phase in which the current flowing thereto is detected by the reference current detectors and the phase in which the current flowing is detected by the other current detector, the correcting unit calculates a gain correcting coefficient based on a detected current value of the reference current detector and a detected current value of the other current detector and corrects the detected current value of the other current detector.

Abstract: A method for controlling an electrically actuable parking brake is described. In this method the cutoff current of the electric motor is varied to compensate for example for changes in the application force associated with aging or wear or for changes in the application force due to changes in the resistance and/or temperature of an electric motor.

Abstract: Various component parts of a driver circuit for drive sources such as electric motors and clutches, such as relays and FETs as well as the drive sources can be tested by selectively energizing the relays and evaluating the voltage levels of the selected points by using the first and second test voltage detection circuits. This testing process is typically executed before the power up of the drive circuit. The test current is so small that the drive sources would not be inadvertently activated and various components would not be damaged even when there is any faulty component in the driver circuit. When any faulty component is detected in the testing process, the driver circuit may be prevented from being powered up so that any undesired operation of the drive sources or permanent damage to various components owing to such a faulty component may be avoided.

Abstract: A circuit for inhibiting a protection device of a motor includes first, second, and third comparators and an inhibit signal generator. The first comparator is operable to determine if a motor current signal associated with the motor exceeds a starting threshold to identify a starting state of the motor. The second comparator is operable to determine if the motor current signal exceeds an inrush threshold to identify a transition from the starting state to an inrush state of the motor. The third comparator is operable to determine if the motor current signal falls below a running threshold to identify a transition from the inrush state to a running state of the motor. The inhibit signal generator is operable to deassert an inhibit signal for inhibiting the protection device responsive to the third comparator identifying the running state.

Abstract: A motor torque control apparatus for an automotive vehicle includes a transmission which has either one of a fixed speed ratio and a variable speed ratio; at least one motor/generator coupled with the transmission as a propelling power source of the vehicle, a power of the power source being transmitted to a road wheel for propulsion of the vehicle through the transmission; and a controller configured to be electrically connected to the motor/generator for motor torque control. Moreover, this controller includes a disturbance observer that estimates a driving force, and a motor torque control section that controls the driving force estimated by the disturbance observer, to bring the estimated driving force closer to a target driving force by way of servo control.

Abstract: In a motor-driven shift position switching device, when the difference between a target position and the rotation position of a rotor has become smaller than a prescribed value in a motor feedback control, a transition is made to a deceleration control. A phase lead correction amount for correcting the phase lead of the current supply phase with respect to the rotor rotation phase is set in accordance with the rotor rotation speed. Thus, proper braking force suitable for the rotor rotation speed is exerted on the rotor and the rotor can be decelerated smoothly as it approaches the target position. Further, in the period when the current supply to the motor is kept off, the shift position switching determination ranges are set wider than in the period when the current supply to the motor is on.

Abstract: A control apparatus for an electric power steering system is provided, which controls a motor for applying assist steering torque to a steering line of a vehicle at least according to steering torque signal of the steering line, vehicle velocity signal and motor current signal. The control apparatus includes a target current controller for setting target current signal for driving the motor, a deviation calculator for computing a deviation between the target current and motor current signals, a deviation adjuster for adjusting the deviation with a variable gain according to the vehicle velocity signal, a proportional element for executing proportional control for the motor, an integral element for executing integral control for the motor and an gain adjuster for adjusting the gain according to a differential of the steering torque signal.

Abstract: The invention relates to a method for the commutation of a brushless direct current motor in which the position of the rotor in respect of the stator is determined directly or indirectly and an external operating voltage is applied, at a preset commutation angle, to the at least one motor winding depending on the determined rotor position. In accordance with the invention, the motor is preferably switched periodically back and forth between a second optimized commutation angle and the first, original, preset commutation angle. If a change in rotational speed results from switching between the commutation angles, the new operating point deviates from the old operating point. To compensate for this difference in speed, not only is the pre-commutation angle changed but the motor voltage is also changed.

Abstract: A first and a second motor drive amplifiers connected to a motor drive power supply include a first and a second memories which store specifications of the amplifiers, respectively. A memory provided in a power supply unit stores an overcurrent detection value for detecting an overcurrent according to the specifications of the respective motor drive amplifiers. A microcontroller reads the specifications from the first and second memories, and integrates overcurrent detection values corresponding to the respective specifications. If a current sensor detects that a current exceeding a reference value calculated based on a set integrated value, the current sensor outputs an overcurrent detection signal.

Abstract: A directional load is capable of operating in multiple directions. For example, a directional motor may rotate in clockwise and counterclockwise directions. A directional load driver generates output signals causing the directional load to operate in one of the directions, thereby providing a requested function. The requested function is identified using an input signal, such as a state-encoded input signal. The state-encoded input signal could be received by the directional load driver over a single wire or through a single input pin. Under the control of the directional load driver, the directional load could perform any of a wide variety of functions. In automotive applications, the directional load could open or close a window, lock or unlock a door, or open or close a door. In other applications, the directional load could be used with a residential door lock, a home automation system, or an industrial control.

Abstract: A method is described for regulating the average electromagnetic torque of a polyphase rotating electrical machine, supplied with a polyphase voltage and a polyphase current that are generated by an inverter. The method comprises a step of controlling the machine, using an exact response control process to do this, a step of determining the value of the harmonics of the voltage and/or the current which are generated by the inverter, and a step of calculating the instantaneous torque set point as a function of the value of the harmonics and an average torque set point, so as to produce an instantaneous torque set point suitable for limiting the difference between the average of the instantaneous electromagnetic torque, between two successive regulation times, and said average torque set point.

Abstract: Control apparatus (30) forcefully stops inverter (14) and inverter (31) when DC/DC converter (12) is anomalously stopped. Additionally, when one of inverters (14, 31) is anomalously stopped while DC/DC converter (12) is normal, control apparatus (30) forcefully stops the other inverter. Then, when a recovery condition is satisfied after the other inverter is forcefully stopped, control apparatus (30) recovers the other inverter.

Abstract: A method of controlling a motor (106) used to drive a screwdriver bit (105) such that screws (107) are seated to the optimum point of grip between the screw (107) and the work piece material. An electronic control circuit controls the speed and output torque of the motor (106). The control system utilizes pulse width modulation (PWM) to control motor (106) speed and torque. The PWM signal controls the duty cycle of the transistors that supply current to the motor (106). The amount of current flowing through the motor (106) coils is proportional to the amount of torque the motor (106) is producing. Motor (106) current is measured as voltage produced across a precision resistor that is in series with the motor (106) coils. As the current in the motor (106) increases, the voltage across the resistor increases (V=IR).

Abstract: The sensorless motor driving apparatus according to the invention may include: a timing generation circuit generating a timing signal at intervals T; a driving signal generation circuit receiving the timing signal and generating, at the intervals T, pulse signals, the number of which M (=m×L+k) is defined by a sum of a predetermined number k and a product of the number of statuses L of the rotor and an integer (m) equal to or greater than 1; and an amplitude control circuit switching between commutation patterns of the driving signal in synchronization with the pulse signals.

Abstract: A direct current motor for an engine throttle control is driven with a motor current of 100% duty ratio, when a throttle valve is to be moved from one throttle position to another or when the movement of the throttle valve is to be braked. The motor current is limited to a limit level, when the motor locks, that is, when the motor current continues to be in excess of the limit level for more than a predetermined period. The motor may be driven with a limited current at initial stages of moving the throttle valve, and with a further limited current when the motor lock is detected. The motor current is finally shut off, when the throttle valve is not rotated to the target position after the continuation of the limitation of the motor current for more than a predetermined period.

Abstract: A compressor driver for a compressor is provided, wherein at the start of the compressor, a phase of the current flowing in the motor is controlled to be ahead of an induction voltage, then the advancement of the phase is controlled to decrease. Under an unstable condition to detect a position, such as at the start under pressure-difference, the foregoing control allows the phase to advance up to the current-phase where the max. torque can be produced, thereby drawing the instantaneous max. torque of the motor for starting the compressor. Then the control reduces the advancement for obtaining a stable operation.

Abstract: An arrangement and a method for starting a slip-ring machine, the arrangement comprising a frequency converter arranged to be connected between a supply network and a rotor of the slip-ring machine for controlling the slip-ring machine, and starting means for starting the slip-ring machine. The starting means are arranged between the frequency converter and the rotor of the slip-ring machine, whereby the frequency converter is arranged to control the magnitude of the current of the rotor of the slip-ring machine in connection with starting the slip-ring machine.

Abstract: A control system for controlling the work output delivered to a floor surface by a work tool associated with a floor maintenance machine, such as a burnisher, is provided. In one embodiment, a voltage regulator regulates the voltage provided to the motor assembly that drives the work tool. A current sensor monitors the motor current drawn by the motor assembly and provides a signal representative thereof to a controller. The controller also receives as an input a work selector signal representative of a desired level of work output. Based on the work selector signal and the sensed motor current, the controller provides a control signal to an actuator. In response to the control signal, the actuator raises or lowers the work tool relative to the floor as need to control the work output delivered to the floor.

Abstract: The invention provides a method for controlling current in a direct current motor having a back emf constant (ke), which may be a function of field current if the direct current motor is a field wound machine, and motor resistance (Rs) in all 4 quadrants of operation. The method includes the step of rotating a motor shaft of the direct current motor with a controller by applying a first voltage across the direct current motor's terminals. The first voltage corresponds to a first value of current passing through the armature windings of the direct current motor. The method also includes the step of determining a maximum value of current to pass through the armature windings of the direct current motor. The maximum value of current is selected to prevent undesirable over current conditions, such as thermal overload as one example. The method also includes the step of receiving a signal corresponding to a desired motor speed (?*) with the controller during the rotating step.