Abstract: A floppy disk control circuit enables a floppy disk apparatus to operate at high speed while current consumption is suppressed to no more than 500 mA, i.e. the maximum allowed current of an apparatus using a USB interface. The floppy disk control circuit outputs a reference clock to a spindle motor drive circuit that drives the spindle motor in accordance with the reference clock to rotate a floppy disk. The floppy disk control circuit outputs a slow reference clock for a low rotational speed corresponding to the maximum allowed current at the commencement of the start-up of rotation of the floppy disk and outputs a fast reference clock for a high rotational speed after lapse of a predetermined time from the commencement of the start-up of rotation.

Abstract: An apparatus for controlling a motor in a washing machine, which includes a speed sensor for measuring speed of the motor, and a controller that compares the measured speed with a target speed to estimate a motor power applied to the motor, adjusts a running rate of the motor according to the comparison, and controls the motor according to the adjusted running rate. The motor power is estimated based on the motor speed, and the running rate is adjusted down if the estimated motor power is too high, thereby preventing overheating of the motor and an inverter, which may be caused in wash or rinse cycles. The apparatus can be implemented without using a temperature sensor, thereby reducing economic burden. Further, the motor does not stop due to an increase in the temperature of the motor, thereby preventing an unnecessary increase in the time required to complete washing.

Abstract: The invention provides an electrically movable vehicle drivable by a simplified mode of control and a control program for driving the vehicle. A normalized value Y? representing translation motion and a normalized value X? representing turning motion are fed from a command value input unit 110 to a velocity command value calculating unit 120. The calculating unit 120 determines a translation velocity command value Vg—trg based on the normalized value Y?. The calculating unit 120 determines a turn angular velocity command value ?f—trg that will always satisfy Expression (2–4) for preventing the vehicle from falling down. The translation velocity command value Vg—trg and the turn angular velocity command value ?f—trg determined by the unit 120 are fed to a control command value calculating unit 130, which calculates control command values for left and right drive wheels. The control command values are fed to a motor control unit 140 to control motors Mr, Ml and control the drive wheels.

Abstract: A serial fan set and rotation speed-matching curve generation method thereof are provided. The serial fan set comprises a rotation speed control module, a first fan and a second fan, in which the rotation speed control module is used to receive the power signal and produce the rotation speed driving signal corresponding to the power signal in accordance with the relations of the rotation speed-matching curve, so that the first fan and the second fan are operated at the matching rotation speed, thus producing the optimum operation efficiency and achieving the purpose of controlling the serial fan set.

Abstract: The invention relates to a method for controlling a brushless electric motor for operation within a specified supply voltage range, a motor control controlling the winding voltage by means of pulse width modulation (PWM) and regulating the rotational speed to a specified speed. According to the invention, the motor is so rated that the nominal rotational speed is just achieved at the nominal operating point at the nominal supply voltage and at the maximum PWM ratio.

Abstract: A system for variable speed motor control provides continuous variable speed motor controller for each motor or motor application within a family of multi-tap motors while using a single controller. The single controller utilizes a wave chop technique providing variable speed motor control through the operating range for each motor tap and seamlessly passes the motor control to each succeeding tap to provide smoothly varying and continuous variable speed motor control throughout the operating range of the multi-tap motor. The system can use a small wave chop firing angle for each tap, thus maximizing the signal to the motor for each tap and minimizing heat build up in the motor. By selecting the controller to operate on a tap basis, an entire family of motors or motor applications can be accommodated with a single controller and apparatus.

Abstract: A drive train for a hybrid electric vehicle has an engine, first and second motor/generators, a third motor, and a transmission in connecting relationships with the engine, the motor/generators, and the third motor. The transmission has planetary gear sets to be shifted among a plurality of running modes including a large driving force running mode. A controller controls surplus power caused by power balance between the first and second motor/generators to be supplied to the third motor when the surplus power is generated and the vehicle starts with the transmission being operated in the large driving force running mode.

Abstract: An apparatus, method and system of wash action control for an automatic washing machine. A manually operable user interface allows selection from between a plurality of discrete agitation speed selections which comprise at least a continuous speed agitation mode for a given agitation period during a wash cycle and an intermittent speed agitation mode for at least a part of a given agitation period. The intermittent speed agitation mode automatically varies agitation speed between at least two sub-periods of the given agitation period. The variation in agitation speed can be between a faster and a slower speed or a certain speed and no agitation.

Abstract: In a travel control method for an electric vehicle, an accelerator angle is obtained from a position of an accelerator lever. An accelerator percentage is determined in accordance with the accelerator angle. The ON times of first and second brake buttons are read. Brake percentages of first and second brakes are determined in accordance with the ON times of the respective first and second brake buttons. A control value for a first electric motor is determined by correcting the accelerator percentage with a corrected brake percentage of the first brake obtained by applying an influence of the brake percentage of the second brake to the brake percentage of the first brake. A speed of the first electric motor is controlled using the control value of the first electric motor.

Abstract: A dual motor configuration 10 is provided for driving two fans for moving air to cool an engine. The dual motor configuration includes a primary brushless motor 18 constructed and arranged to be electronically controlled to drive a first fan 16 over a range of speeds. A secondary brush motor 24 is constructed and arranged to be electronically controlled to drive a second fan 22 over a range of speeds. The secondary brush motor includes an electronic switching device 26 associated therewith for receiving a pulse width modulated signal for controlling speed of the secondary brush motor. Thus, different combinations of speeds of the first and second motors can be selectively chosen to meet cooling requirements.

Abstract: In order to improve a control device for operating a load circuit having at least one electric motor, this control device comprising a control stage which generates a pulse width modulated control signal, a power stage supplying the load circuit and having an electronic switch activated by the pulse width modulated control signal, a freewheeling element connected in parallel to the load circuit and a blocking monitoring means which generates a measurement switch-off interval by suppressing at least one switch-on interval of the pulse width modulated control signal, monitors the voltage in the load circuit during the measurement switch-off interval, compares it to a limit value and generates a blocking state signal in accordance with the comparison, in such a manner that a differentiated analysis of the voltages occurring in the measurement switch-off interval is possible it is suggested that for monitoring at least two electric motors connected in parallel in the load circuit the blocking monitoring means car

Abstract: An apparatus and method for the controlled dynamic braking of a DC motor in a tape transport device are provided. A PWM state device includes a plurality of state transition paths, each path having an initial state, representative of a tape profile, including a predetermined range of tape velocities, relative amounts of tape on each reel and an initial tape tension, and at least one subsequent state. When a low power event is detected, one of the state transition paths is selected, based upon a current tape profile, and an associated PWM signal is transmitted to the motor. An energy storage device provides power to the PWM state device during the low power event. The PWM signals follow the selected transition path to modulate the current generated by the motion of the motor and thereby create a decelerating force while substantially maintaining the initial tape tension.

Abstract: A control system for individually controlling power from a single voltage source to a plurality of motors is described. A chopper circuit, in conjunction with the control system, generates drive-pulses, which operates the IGBT switching devices to sequentially provide pulses to each motor.

Abstract: A variable speed drive control system operates a variable speed drive to power a first load from a power source simultaneously powering a second load. An AC reactive power is monitored which may comprise or consist of an AC reactive power of the second load. Responsive to the monitored AC reactive power, the variable speed drive is controlled to counter the AC reactive power of the second load.

Abstract: An electric vehicle driven by a pair of left and right electric motors is provided. The vehicle includes a controller for controlling the start of the vehicle. The controller performs such control as avoiding brake drag caused by the operation of the electric motors before the elimination of the braking of a pair of left and right parking electromagnetic brakes.

Abstract: A dual motor configuration 10 is provided for driving two fans for moving air to cool an engine. The dual motor configuration includes a primary brushless motor 18 constructed and arranged to be electronically controlled to drive a first fan 16 over a range of speeds. A secondary brush motor 24 is constructed and arranged to be electronically controlled to drive a second fan 22 over a range of speeds. The secondary brush motor includes an electronic switching device 26 associated therewith for receiving a pulse width modulated signal for controlling speed of the secondary brush motor. Thus, different combinations of speeds of the first and second motors can be selectively chosen to meet cooling requirements.

Abstract: A starter motor is prevented from being rotated together with an engine after the start of a engine. When motor speed exceeds the cranking speed after the start of the engine, a speed judging section 36 judges that the starter motor is rotated together with the engine. A current-supply stopping section 38 commands to stop energizing a motor 3a in response to the judge. After the electricity supply is stopped, if the rotation speed is reduced to a value close to the cranking speed, judging section 36 outputs a signal to cancel the current-supply stopping commands from the current-supply stopping section 38. The detection of the motor speed is also continued even after the ignition, and if the speed is further increased, the speed detection is stopped. If the speed is increased to a value showing complete explosion, the speed judging section 36 switches the relays to a generator.

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

Abstract: A method for generating a compensated torque command signal to be applied to an electric power steering motor is disclosed. In an exemplary embodiment, the method includes generating an assist torque command signal responsive to a measured vehicle speed and an input steering torque signal. An assist dependent damping torque signal is generated, the assist dependent damping torque signal responsive to the assist torque command signal, the measured vehicle speed and a compensated motor velocity output value of the electric power steering motor. The assist dependent damping torque signal is then subtracted from the assist torque command signal.

Abstract: A computer system or other electronic system includes a plurality of cooling fans configured to operate in parallel. The cooling fans are operated in a manner to decrease the operating time of a fan. The cooling fans can alternate in operation. Thus, operating time is more equally divided between the two cooling fans and the hours of operation and number of rotations of the fans is more nearly equal. In an embodiment to reduce noise, two fans run at a lower speed instead of one fan at a higher speed. In an embodiment, a fan operates with a reduced speed which maintains a desired operating temperature. In an embodiment a thermal table is stored in BIOS (basic/input output system).

Abstract: A movable barrier operator includes a wall control switch module having a learn switch thereon. The switch module is connectable to a control unit positioned in a head of a garage movable barrier operator. The head unit also contains an electric motor which is connected to a transmission for opening and closing a movable barrier such as a garage door. The switch module includes a plurality of switches coupled to capacitors which, when closed, have varying charge and discharge times to enable which switch has been closed. The control unit includes an automatic force incrementing system for adjusting the maximal opening and closing force to be placed upon the movable barrier during a learn operation. Likewise, end of travel limits can also be set during a learn operation upon installation of the unit.

Abstract: A device and a process for controlling the motor drives (121) of textile machines, comprising at least one “encoder” (101), capable of controlling the number of revolutions of each motor (121), and at least one central electronic unit (111) processing the data originating from all the motor drives (121), based on an application program containing the synchronizing data between the individual motors (121) and the technological operating parameters of the textile machine.

Abstract: A wheelchair having a seat and a plurality of wheels for rolling the wheelchair along a ground surface. A plurality of legs are provided for supporting the seat. Each of the legs is positioned between the seat and one of the wheels. A plurality of struts are also provided. Each of the struts couples a first of the legs to a second of the legs. Each of the legs bears only compressive force in supporting the seat, and each of the struts bears only tensile force. A foldable wheelchair formed from a seat bottom and a seat back pivotally coupled to the seat bottom. The seat back is movable between a folded position and an unfolded position. The seat bottom has a back end formed from a first curved shape, and the seat back has a bottom end formed from a second curved shape. The first curved shape of the seat bottom is sized to mate with the second curved shape of the seat back when the seat back is in the unfolded position.

Abstract: A wheel module for the control of the braking force on a wheel of a vehicle with an electrically controlled braking system (EBS), in which the need for data transfer to other wheel modules, or to a central module, if present, is reduced considerably. All magnitudes required for an ABS regulation of a wheel such as, for example, vehicle reference speed, are calculated directly in the wheel module according to the invention, so that these magnitudes need not be transmitted from a central module via a data bus.

Abstract: A motor control unit (1) includes a white noise generator (8), an instruction switch (9) for switching between an input control instruction (Vins) and a white noise output of the white noise generator (8), a controller (10) for feedback controlling the motor drive velocity, a detection unit (13) for detecting and sampling the real velocity of a motor or a load at a predetermined period, a first Fourier transformer (15) for Fourier-transforming the control instruction data (Cins) together with the sampled velocity data (Vm), and a first frequency characteristic operation unit (16) for calculating the frequency characteristics in a range from the velocity instruction (Cins) to the sampled velocity (Vm) based on output data of the first Fourier transformer (15), thus obtaining the frequency characteristics in a short period without necessity of a servo-analyzer.

Abstract: A dueling or racing roller coaster ride has tracks which approach or cross over each other at near miss locations. A controller system controls the timing of launch of a roller coaster vehicle on each track to better achieve consistent simultaneous arrival of the roller coaster vehicles at the near miss locations, to provide increased thrills and excitement to the riders. The control system determines the loaded vehicle weight via current draw on the track side vehicle motors. The control system generates a vehicle performance parameter, based on past vehicle speed over the track, to compensate for roller resistance and aerodynamic factors. The vehicle weight information and performance parameters are used to determine which vehicle to launch first, and the amount of delay between launching the vehicle on the first track and launching the vehicle on the second track, to better achieve simultaneous arrival at one or more locations.

Abstract: Control system for controlling a dynamic physical system. New, substantially decoupled axes are derived from physical axes of a dynamic system. Closed-loop controllers operate on signals representing the new or synthesized axes to control the coordinate parameters. Control signals are then converted into the original physical axes to generate signals to control the original axes. A preferred embodiment is the application of the control technique to a gantry machine having three degrees of freedom. Actual coordinates are converted to one linear coordinate and one rotational coordinate. The bandwidth of controllers operating on these two coordinates are separated so that crosstalk is diminished and performance improved.

Abstract: To drive a lens part by a servo motor, an automatic controller turns on the first switch to input a desired value to an error amplifier from a final controlling element, and turns off the second switch to activate a feedback circuit which performs negative feedback. On the other hand, if the desired value is 0, or if the final controlling element does not work, the automatic controller turns off the first switch to shut out the desired value from the final controlling element, and turns on the second switch to activate the feedback circuit which performs positive feedback. This enables hand operation of the lens part with support of the positive feedback.

Abstract: A torque controller system provides improved torque distribution as a function of wheel diameter size in a vehicle propelled by electric traction motors. The system includes one or more torque processors each having a multiplier coupled to receive an input signal and configured to produce an output signal which is the product of the input signal and a variable multiplier value generated by a respective torque distribution generator based on a predetermined torque distribution control function.

Abstract: An amusement ride provides an interactive experience to its passengers. The amusement ride includes at least one ride vehicle movable along a track. The amusement ride senses inputs from at least one passenger that affects various elements of the ride. The elements can be the speed of the vehicle, acceleration of the vehicle, direction of travel, orientation of the ride vehicle or the like. The inputs can be audible inputs or optical inputs, water spray, or can be activated manually by the passengers.

Abstract: A wash action control system is used to control the agitation speed of a washing machine. The invention includes a wash speed selection switch which controls the agitation speed of the agitator. The wash speed selection switch has an infinite number of possible wash speed settings and includes various secondary switches for affecting various aspects of the wash speed control.

Abstract: To drive a lens part by a servo motor, an automatic controller turns on the first switch to input a desired value to an error amplifier from a final controlling element, and turns off the second switch to activate a feedback circuit which performs negative feedback. On the other hand, if the desired value is 0, or if the final controlling element does not work, the automatic controller turns off the first switch to shut out the desired value from the final controlling element, and turns on the second switch to activate the feedback circuit which performs positive feedback. This enables hand operation of the lens part with support of the positive feedback.

Abstract: A control device for controlling a plurality of motors of an air conditioner comprises a plurality of power circuits each for supplying a corresponding DC voltage to drive a respective motor. Motor driving circuits, each having a plurality of switches, supply the DC voltage from a corresponding power circuit as an AC voltage to windings of the corresponding motor. A rotational position of each corresponding motor is detected, and a position detecting signal is generated dependent thereon. Switch driving circuits, each receptive of a corresponding driving signal, drives the plurality of switches of each corresponding motor driving circuit. A single microcomputer controls the rotation of each of the plurality of motors by generating the plurality of driving signals.

Abstract: A pair of DC motors, each having a shunt-connected field winding, are interconnected such that current supplied to the shunt field winding of one of the motors is proportional to the armature current in the other of the two motors when the speed of the other motor is between predetermined maximum and minimum speeds.

Abstract: The invention relates to a system for directing an apparatus, such as a crane bridge (1), moving on wheels along rails, which apparatus comprises a specified drive arrangement (m.sub.1, m.sub.2, m.sub.3, m.sub.4 ; k.sub.1, k.sub.2) on both sides of a roadway defined by rails (3), and which system comprises in the apparatus at least on one side of the roadway at least two successive detectors (d.sub.1, d.sub.2) in the direction of the rail (3) for measuring a lateral distance (l.sub.1, l.sub.2) of a specific part of an edge (e.sub.1, e.sub.2) of the apparatus to be driven from the rail, a control loop (CS) guiding the drive arrangements, a controller of the loop being able to direct the distance measurements (l.sub.1, l.sub.2) of the detectors (d.sub.1, d.sub.

Abstract: A postage meter has a print rotor rotated by a motor and the motor is capable of being started and stopped under processor control. State variables are established within a nonvolatile memory. The rotor begins in its home position. When a mail piece such as a letter is detected by a letter sensor, the processor sets a state variable. At some point (either before loss of power, or after restoration of power) the postage value to be printed is booked into the accounting register. The rotor motor is started. At some point (either before loss of power, or after restoration of power) the rotor reaches its home position again. A state variable is cleared. In this way, it is possible, even after the loss and restoration of power, to distinguish between a rotor that is in its home position because it has not yet printed postage (but needs to do so) and a rotor that is in its home position because the printing of postage has been completed.

Abstract: A smoke exhauster includes a CPU, two motors and a switching circuit connected to the CPU. The switching circuit includes a common contact, a parallel contact for connecting the motors in parallel, and a series contact for connecting the motors in series. The common contact is connected to the parallel contact for allow higher power supply to start the motors, and the common contact is connected to the series contact for reducing power supply to the motors in order to reduce the rotational speed of the motors. The motors are connected in series after the motors are started.

Abstract: A traction enhancing system detects and corrects wheel slip and enhances wheel traction in a railroad locomotive having a plurality of wheel pairs for engaging a pair of rails and a traction motor operatively associated with each wheel pair. The locomotive includes an electrical source responsive to an applied level of excitation and is operatively coupled to the traction motors for controlling the power applied thereto. The traction enhancing system includes a plurality of current measuring devices adapted to measure current drawn by each traction motor, and a plurality of voltage measuring devices adapted to measure a voltage of each traction motor. A computer receives the current and voltage measurements and is configured to detect wheel slip between the wheel pairs and the rails by calculating a change in the current and voltage measured over a predetermined period of time.

Abstract: The rotor spinning machine includes a plurality of asynchronous motors for driving the operating elements of the machine. The motors run up from a standstill condition to an operating speed under the initial mass load of the operating elements. The machine includes a single soft-start control apparatus control circuit configured with the motors and the soft-start control apparatus for individually and successively connecting the motors to the soft-start control apparatus in a predetermined hierarchy.

Abstract: The process has an open control loop which detects the total current intensity of actuators and supplies it to a microprocessor. In a modulation mode the microprocessor successively generates at its output a modulated set value signal for each actuator, the set value signals lying below the response level of the process. The microprocessor then determines compensation values from the total current signal with which the set values of the actuators are corrected. The (regulating) speed of a control is thus combined with the accuracy of a regulation. The hardware expenditure (costs) is minimized thanks to the total current detection instead of the individual current detection.

Abstract: A rail vehicle may be provided with a plurality of individual wheels (11, 12, 21, 22) and traction motors which are supplied with power on a wheel block by wheel block basis by means two control devices each including open loop and closed loop controls (6, 8). The wheel speeds (n11, n12, n21, n22) are used to determine two wheel block speeds (n1, n2), from which an actual speed difference value (.DELTA.n) is calculated. A manipulated variable (.DELTA.m*) is produced from a comparison of the actual speed differences value (.DELTA.n) to a set speed difference value (.DELTA.n*). A set traction lever value (m,) is increased and reduced by this manipulated variable (.DELTA.m). Consequently, the wheel blocks (1, 2) obtain a definitively set speed difference corresponding to the arc radius (r), whereby the running behavior on bends is significantly improved by virtue of the satisfied rolling condition.

Abstract: The invention relates to apparatus for controlling a plurality of electric motors. The apparatus includes drive means for applying electrical power to the motors at a predetermined current or voltage. Sensor means are provided for sensing the load on each motor. Comparator means, which include polarity detection means for generating at least one polarity signal representative of the combined polarity of the loads, and summing means for deriving a magnitude signal representative of the loads, are used to determine the relative magnitudes of the loads. Control means are arranged to generate a compensation signal which is applied to the drive means to reduce the power applied to the more heavily loaded motor or motors. The control means typically includes switching means responsive to the polarity detection means for determining the polarity of the magnitude signal, thereby to obtain the compensation signal. The invention extends to a method of controlling a plurality of electric motors.

Abstract: A main spindle rotation control method capable of preventing a workpiece from being twisted during the delivery of the workpiece between two main spindles of a machine. When the rotating speeds of first and second main spindles (100, 200) reach a synchronous rotating velocity as a result of a speed loop control executed by velocity control sections (111, 211) of first and second spindle control circuits (110, 210), position loop control is executed by position control sections (112, 212) of these control circuits, and each main spindle is driven to be decelerated in accordance with the rotational phase of each main spindle, and the velocity loop control is then executed again, to bring the main spindles to rotate in the same phase and at the same synchronous rotating speed. When the delivery of the workpiece (300) between the main spindles is started under this condition, integral control in both the velocity control sections is invalidated.

Abstract: This invention relates to a speed control circuit for an electric motor. It includes a controller having a plurality of input circuits and an output circuit adapted to be connected to one of a plurality of direct current motors. The controller includes means responsive to an alternating signal on a selected one of said input circuits for generating and maintaining a unidirectional motor-energizing voltage of predetermined magnitude in the output circuit whereby the speed of said one motor may be controlled. The controller further includes Hall cell devices coupled to a plurality of motors, respectively, for generating the alternating signal in response to energization of a selected motor.

Abstract: A hoist drive for a double hoist carrying member having a hold hoist drum, a hold rope connected to the hold hoist drum and from which the carrying member is suspended, and a hold motor for rotating the hold hoist drum to raise and lower the carrying member. The hoist drive further includes a close hoist drum, a close rope connected to the close hoist drum and from which the carrying member is suspended, and a close motor for rotating the close hoist drum to raise and lower the carrying member. During raising of the carrying member, the hold and close motors are each supplied with a.c. power at different preselected frequencies. The hold and close motors each operate along a first pair of intersecting frequency to torque curves during a raising operation in which the hold motor curve is steeper than the close motor curve.

Abstract: A control system for a washing machine which controls an induction motor to generate an optimum torque in accordance with a load amount of laundry and whether the washing machine is operating in a washing or drying mode. The control system drives the motor at an optimum torque by varying the input voltage in accordance with the sensed load and sensed mode of operation. This allows a washing machine according to the invention to operate more efficiently and with less noise than conventional washing machines.

Abstract: An apparatus and method for controlling the velocity of a motor controls the motor by fuzzy inferential reasoning in a transitional period when the motor is started, changed in speed, reversed or stopped. Such fuzzy control eliminates an increase in the length of the transitional period caused by a limitation in supply current under conventional PLL control and makes possible a rapid transition to a target velocity. A plurality of fuzzy rules are provided and one of these fuzzy rules is selected in accordance with the length of the previous transitional period, thereby suppressing the effects of load fluctuation and the influence of a fluctuation in torque caused by a rise in temperature. Therefore, the length for transitional control of a motor can be shortened and the apparatus can be reduced in size.

Abstract: A ring spinning machine with various driving systems 10, 12 for driving spindles, driving arrangements, ring rails and the like is regulated in the case of power failure down to a zero revolution range while maintaining preselected revolution relationships. The driving system which is allocated to the load with the greatest effective inertia serves, at first, for the supply of the other driving system in a generator service. Only in a lower revolution range are the driving systems backed via a battery of relatively low capacity.

Abstract: An apparatus for selectively controlling a plurality of electric motors for driving individual work objects, the apparatus including an electrical switch which is adapted to produce predetermined speed signals for the electric motor selected, a programmable controller disposed in signal receiving relation relative to the electrical switch and which is adapted to generate a predetermined signalling sequence in response to the signal received from the electrical switch, a variable speed motor drive electrically coupled with the programmable controller, and with the electric motor selected, the variable speed motor drive selectively driving the selected electric motor at a predetermined speed in response to the signalling sequence received from the programmable controller, and a sensor adapted to indicate the work performed by the electric motor whereby the electric switch may be selectively adjusted to control the operation of the electric motor selected.

Abstract: A control circuit for a fractional horsepower fan motor connected between hot and neutral wires in and AC circuit is shown. The control circuit includes two or more duplicate branches. Each branch is serially connected, and each branch includes a triac, series resistor and series capacitor. The triac has a gate terminal which is connected to an optical coupling circuit for isolation and responds to a control signal from a low voltage small current source. In an alternative embodiment, a single triac and optical coupling circuit can be used with different capacitors being switched in or out of the circuit.