Abstract: An apparatus for linear compressor includes a drive unit configured to apply a test signal to the linear compressor, a current detection unit configured to detect a motor current of the linear compressor, a voltage detection unit configured to detect a motor voltage of the linear compressor, and a controller configured to acquire plural inductances varied according to a size of the motor current, based on a change of the motor current and the motor voltage which are acquired according as the test signal is applied.

Abstract: A fan and a motor drive device thereof are provided. The motor drive device is configured to drive a motor and includes a control management unit and a voltage converter. The control management unit classifies target rotation speed signals provided by an ECU into multiple rotation speed ranges, each corresponding to a specific output duty ratio. The control management unit receives a target rotation speed signal transmitted from the ECU in a real-time manner, and output a voltage regulating signal, which is a pulse width modulation signal having a duty ratio corresponding to one of the rotation speed ranges in which the target rotation speed signal transmitted from the ECU falls. The voltage converter is connected between a power source and the motor, and is configured to regulate a voltage outputted to the motor in response to the voltage regulating signal having the specific duty ratio outputted from the control management unit, to regulate a rotation speed of the motor.

Abstract: A motor drive device and a motor drive method for a vehicle electric pump. The device and the method set a target value according to an instruction value of a motor control amount and control the motor of the vehicle electric pump based on the target value. When the instruction value is greater than an actual control amount, the instruction value is set to the target value. Meanwhile, when the instruction value is less than the actual control amount, the actual control amount is set to the target value when the actual control amount is less than a value less than a previous target value by a predetermined value, and the value less than previous target value by predetermined value is set to the target value of this time when the actual control amount is greater than the value less than previous target value by predetermined value.

Abstract: A voltage increasing control circuit is connected to a power supply to regulate power supplied to a load. The voltage increasing control circuit includes a voltage increasing unit configured to increase voltage that is supplied from the power supply, and supply the voltage to the load. A power estimation unit determines whether or not to increase the power supplied to the load. A voltage control unit controls the voltage increasing unit. When the power estimation unit determines to increase the power supplied to the load, the voltage control unit controls the voltage increasing unit to increase the power supplied to the load.

Abstract: A control circuit for a fan includes a fan controller, a switch controller, and a frequency detector. When a pulse-width modulation (PWM) signal output pin of the fan controller outputs PWM signals, the frequency detector outputs a high level signal, connecting an input pin of the switch controller to an output pin of the switch controller. The fan receives the PWM signal. When the PWM signal output pin of the fan controller does not output PWM signals, the frequency detector outputs a low level signal, such that the output pin of the switch controller does not output any signal. In this state, the fan receives a high level signal through a resistor and a power supply, enabling the fan to continue operating.

Abstract: A motor drive control apparatus for performing motor control that is stable and has a good efficiency includes: a speed processing unit that generates a first value by converting a second value corresponding to a current speed into a duty ratio; a torque processing unit that generates a third value by converting a fourth value corresponding to a target torque into the duty ratio; and a drive unit that controls switching by a switch included in a complementary switching amplifier by an average duty ratio corresponding to a sum of the first value and the third value to drive a motor connected to the complementary switching amplifier.

Abstract: To provide a power supply device which can reduce energy loss caused due to the forward-direction voltage of a flywheel diode. In a load circuit for subjecting an electronic switch T1 provided between a DC power supply VB and a motor M1 to the PWM control to thereby drive the motor M1, a MOSFET (T2) is provided in parallel to the motor M1. A parasitic diode Dp of the MOSFET (T2) is provided in a manner that its forward direction is in opposite to the flowing direction of a load current ID. The MOSFET (T2) is turned on during a part of a period during which the electronic switch T1 is placed in an off state to thereby flow a circulation current flowing through the motor M1 into the MOSFET (T2). Thus, the energy loss can be remarkably reduced as compared with the case of using the flywheel diode.

Abstract: The invention relates to an electric motor having a stator and a rotor. The electric motor also comprises a controller, wherein the controller is connected to the stator and/or rotor, and is designed for applying current to the stator and/or rotor for rotating the rotor. According to the invention, the controller comprises a pulse width modulator designed for controlling a power output of the electric motor, in order to generate a predetermined number of different current application patterns. The current application patterns each represent a power output of the electric motor, and preferably comprise a time sequence of current pulses, each having a current pulse duration.

Abstract: A motor driving circuit generates pulse driving signals, and controls the ON/OFF state of a switching circuit connected to a coil of a motor which is to be driven, thereby controlling the conduction period of the motor. A driving signal generating circuit generates the driving signals such that they are pulse modulated according to the torque target value for the motor, and outputs the driving signals to the switching circuit. A current detection circuit detects the current flowing through the coil of the motor. A current limiting circuit controls the logical values of the driving signals generated by the driving signal generating circuit such that the current detected by the current detection circuit does not exceed a predetermined current upper limit. The current limiting circuit increases the current upper limit according to the time elapsed in the starting operation of the motor. After the starting operation of the motor, the current upper limit is set to a predetermined fixed value.

Abstract: A fan system includes a control device and a fan device. The control device has a first node, a rotation speed signal generation circuit and a rotation speed reading circuit. The fan device has a second node, a signal transforming circuit, a motor driving circuit, a motor and a fan. The first node is electrically connected with the second node to set up a transmission route between the control device and the fan device. The rotation speed control signal and the motor rotation speed signal are transmitted via the two-way transmission route, and the control device controls the fan device via a wired or wireless transmission route. A motor control device is also disclosed.

Abstract: A fan system includes a connecting device, a controlling device and a fan device. The connecting device has a plurality of pins receiving at least one driving signal and a start signal. The control device is electrically connected to the pins of the connecting device and has a start control unit. The start control unit generates a first enabling signal in accordance with the start signal. The control device synchronously outputs the first enabling signal and the driving signal. The fan device is electrically connected to the control device and has a plurality of fans. The fan device synchronously transmits the driving signal to the fans and synchronously drives the fans to rotate in accordance with the first enabling signal.

Abstract: The invention relates to a circuit for controlling a number of DC motors (M1, M2) capable of being controlled independently of one another, comprising, for each motor (M1, M2), an H-bridge (1A, 1B) made up of a first branch (3) and of a second branch (5), which bridge is intended for the control of the associated motor. According to the invention, the said second branches (5) of the H-bridges (1A, 1B) are produced in the form of two switches (7, 9) forming a branch common to all the H-bridges and rated to accept a current equivalent to the sum of the drive currents so that the said motors (M1, M2) can be controlled simultaneously and independently by applying associated control signals to the first branches (3).

Abstract: A circuit for controlling rotation speed of a computer fan includes a fan header for connecting to a 4-pin fan or a 3-pin fan, a jumper device, an amplifier, and a controller. The jumper device has a first pin for receiving a controlling signal, and connected to a first power source, a second pin connected to the fan header, and a third pin connected to the first power source. The amplifier has an input terminal connected to the third pin of the jumper device via an integrator. The controller has a first terminal connected to an output terminal of the amplifier, a second terminal connected to a second power source, and a third terminal connected to the fan header and connected to a positive input terminal of the amplifier via a resistor. The first pin of the jumper device is selectively connected to the second or third pin.

Abstract: A coil load driving circuit in which generation of radiation noise when a motor is stationary is minimized, includes output buffers that output a PWM pulse to both terminals of a motor; a transfer voltage generating circuit that outputs transfer voltages VTR1, VTR2 proportional to the difference between an input control voltage VIN and input reference voltage VREF; PWM comparators that output PWM signals PW1, PW2 corresponding to the transfer voltages VTR1, VTR2; and an output PWM pulse synthesis circuit that controls the output buffer in accordance with an AND signal of the PWM signal PW1 and an exclusive OR signal EX of the PWM signals PW1 and PW2, and controls the output buffer in accordance with an AND signal of the PWM signal PW2 and the exclusive OR signal EX.

Abstract: A method for controlling an electric motor by using the PWM technique; the control method includes the steps of: applying to the clamps of the electric motor an electric voltage varying in time, which displays a square waveform and consists of a sequence of pulses having a uniform wave period and a variable amplitude; adjusting the average value of the electric voltage applied to the clamps of the electric motor by varying the amplitude of the pulses of the electric voltage; determining, in the case of a variation of the amplitude of the pulses, the overall required amplitude variation; subdividing the overall required amplitude variation in a determined number of partial variations, the overall sum of which is equivalent to the overall required amplitude variation; and gradually varying the amplitude of the pulses of the electric voltage by applying in a sequence a corresponding partial variation to each pulse, so that the difference between the amplitude of a pulse and the amplitude of a following pulse is

Abstract: A method of operating a hand power tool in one embodiment includes generating a variable speed control signal with a solid state switch that corresponds to a selected speed for a motor, generating a pulse width modulated (PWM) signal corresponding to the variable speed control signal, generating H-bridge driving signals for an H-bridge circuit in correspondence with the PWM signal, and selectively coupling a motor to a power source using the H-bridge circuit in accordance with the H-bridge driving signals.

Abstract: The present patent application refers to an actuator for automotive climatization units, of the type designed to be driven by an electric control unit with direct current and low voltage, characterised in that it is provided with an electric motor able to operate at a lower voltage than the voltage delivered by the control unit and characterised in that it is provided with an electronic device able to modify the ascending ramp angle of the voltage of the successive pulses from the said control unit, in such a way that each pulse has an ascending ramp with sloped profile, so that the maximum voltage value of each pulse depends on the pulse duration.

Abstract: A buck converter for use in controlling a motor in accordance with an embodiment of the present invention includes a power input operable for connection to a DC power supply, a switch for selectively connecting the motor to the power supply, a pulse width modulation controller operable to provide a pulse width modulation signal to the switch, wherein the switch connects the motor to the power supply based on the pulse width modulation signal, and a voltage shifting capacitor connected across the switch and in series with a diode. The buck converter may include a shift control device operable to control a voltage across the voltage shifting capacitor.

Abstract: A fan system includes a control device and a fan device. The control device has a first node, a rotation speed signal generation circuit and a rotation speed reading circuit. The fan device has a second node, a signal transforming circuit, a motor driving circuit, a motor and a fan. The first node is electrically connected with the second node to set up a transmission route between the control device and the fan device. The rotation speed control signal and the motor rotation speed signal are transmitted via the two-way transmission route, and the control device controls the fan device via a wired or wireless transmission route. A motor control device is also disclosed.

Abstract: A single low side power transistor switch is used to efficiently control a brushed motor in a forward rotational direction. A boost voltage power supply is used to supply voltage to the brushed motor in a reverse rotational direction and/or braking from the forward rotational direction. A digital device controls the brushed motor rotational speed and rotational directions.

Abstract: An open-loop driving method of a spindle motor includes determining of whether open-loop driving conditions for the spindle motor are met, and adjusting widths of driving pulses applied to the spindle motor according to a predictive speed variation of the spindle motor when it is determined that the open-loop driving conditions for the spindle motor are met.

Abstract: A method of adjusting sensitivity of signal interpretation includes the steps of: continuously receiving an input signal; setting a sampling parameter; sampling the input signal according to the sampling parameter to obtain a plurality of sampling signals; judging whether the sampling signals are the same or not; generating a first control signal according to the sampling signals if the sampling signals are the same; and generating a second control signal according to the input signal if the sampling signals are not the same. A device of adjusting the sensitivity of signal interpretation is also disclosed.

Abstract: A DC brushless fan motor driving circuit has a Hall PWM signal generator, a speed signal generator, a PWM driver and a full-bridge switching circuit. The Hall PWM signal generator obtains a Hall sine wave signal from an external Hall sensor and converts the Hall sine wave signal to a varied Hall PWM signal. The speed signal generator is connected to an external PWM input signal to set speed of a fan motor and a low speed voltage to determine a present speed setting signal. The speed signal generator further obtains the varied Hall PWM signal to compare the present speed setting signal to generate a SPWM signal to the PWM driver. The PWM driver outputs a SPWM signal to the full-bridge switching circuit and then coil current is formed close to a sine wave signal to decrease the electromagnetic noise.

Abstract: A fan system includes a connecting device, a controlling device and a fan device. The connecting device has a plurality of pins receiving at least one driving signal and a start signal. The control device is electrically connected to the pins of the connecting device and has a start control unit. The start control unit generates a first enabling signal in accordance with the start signal. The control device synchronously outputs the first enabling signal and the driving signal. The fan device is electrically connected to the control device and has a plurality of fans. The fan device synchronously transmits the driving signal to the fans and synchronously drives the fans to rotate in accordance with the first enabling signal.

Abstract: A fan system includes a connecting device, a controlling device and a fan device. The connecting device includes a first pin receiving at least one driving signal, and a second pin receiving a start signal, wherein a length of the first pin is greater than a length of the second pin. The controlling device is electrically connected with the connecting device and includes an enabling unit. The enabling unit generates at least one first enabling signal according to the start signal, and the controlling device outputs the driving signal and the first enabling signal. The fan device is electrically connected with the controlling device and includes at least one fan. The fan device transmits the driving signal to the fan and drives the fan according to the first enabling signal.

Abstract: A PWM motor drive circuit includes a drive IC member, a PWM converter circuit and a potential limiter. The drive IC member electrically connects with a motor coil and further includes a pin electrically connected with the PWM converter circuit. The potential limiter has a first terminal electrically connected with a point between the pin of the drive IC member and the PWM converter circuit, and a second terminal electrically connected with a power source to supply an initial voltage to the pin of the drive IC member via the potential limiter. When the motor starts, the potential limiter can adjust of the initial voltage supplying to the pin of the drive IC member so that the drive IC member cannot unexpectedly enter a stop or high-speed mode.

Abstract: A control circuit for controlling rotational speed of a fan for an electronic device includes a temperature detecting unit for detecting an ambient temperature of the electronic device, and outputting a corresponding detection result; a control unit receiving the detection result from the temperature detecting unit, and outputting a corresponding control signal; and an operational unit receiving one or both of the control signal from the control unit and a pulse-width modulation (PWM) signal, and outputting a backup control signal for controlling the rotational speed of the fan, so that the fan can continue operating when needed, even if the PWM signal disappears.

Abstract: An abnormality monitoring device monitors a PWM driving signal output from a driving section of an associated motor control system to judge whether the driving section is operating abnormally. By monitoring the output of the driving section, the monitoring device can detect an abnormality of the driving section before the motor can respond to the abnormal drive signal to a significant degree (e.g., to a degree readily discernable to a rider of a motorcycle on which the motor control system is employed in combination with an electronic throttle system).

Abstract: In a control apparatus for a motor, which rotates a fan, a semiconductor device is connected to the motor in series to drive the motor. An analog driver circuit drives the semiconductor device with an analog voltage. A PWM control circuit drives the semiconductor device with a PWM signal of a frequency of less than several tens. A switching control circuit selects the analog driver circuit and the PWM control circuit when the motor is to be rotated at speeds lower and higher than a predetermined speed, respectively.

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

Abstract: The present invention encompasses a high efficiency pulse width modulator comprising: a variable duty cycle oscillator for receiving an input signal and providing a low level switching signal; a source voltage differentiation dependant positive switching signal circuit for receiving the low level switching signal, a stable reference signal, a sample of a positive supply voltage signal, and an error signal and the providing a positive supply switching signal and a reference signal; a positive supply switching circuit for receiving the positive supply switching signal and providing an output signal to an inductive load; an output voltage dependant negative supply switching signal circuit for receiving the output signal and a negative supply voltage signal and providing a negative supply switching signal; a negative supply switching circuit for receiving the negative supply switching signal and providing clamping of the inductive load to the negative supply, an output sourced charge pump for receiving the output

Abstract: In order to design as inexpensively as possible a control device for DC motors which are provided with a commutator for feeding their motor windings which has at least four sliding contacts, this device comprising a modulation stage which generates at least one control signal modulated as to pulse width with a clock frequency substantially above the motor speed and a control circuit which is controlled by the at least one control signal and has at least one load branch which feeds the commutator and is provided with an electronic switch controlled by the control signal modulated as to pulse width, it is suggested that the sliding contacts be combined to form at least two control groups, that the sliding contacts be combined within each control group to form pairs of sliding contacts and that each control group have its own load branch associated with it.

Abstract: A method of operating a cooling fan in a cooling system for a vehicle includes determining a required speed of the cooling fan. First and second signals are provided to a motor controller operatively connected to a motor having a rotatable portion connected to the cooling fan. The first signal coarsely controls a rotational speed of the motor by adjusting a voltage level provided to the motor and the second signal finely controls the rotational speed of the motor by pulse width modulation so that the cooling fan rotates at the required speed.

Abstract: Embodiments of present invention may provide a motor control drive circuit for driving a motor by receiving signals from a digital signal control device. The motor control drive circuit includes a switching unit receiving signals that have undergone pulse width modulation (PWM signals) in the digital signal control device, and converting a switching state based on the input signals; and a controller receiving from the switching unit switching operational signals that vary according to a duty ratio of the PWM signals, receiving digital signals from the digital signal control device, and varying a voltage gain for control of the drive motor. In the motor control drive circuit of one embodiment of the present invention, motor rotation is controlled by the duty ratio of digital signals without the use of a DAC. This allows for the design of an independent digital signal processing device, and enables compatibility with various digital signal processing devices.

Abstract: A speed control circuit for a brushless dc motor includes a motor drive circuit, a drive member and a PWM control circuit. The motor drive circuit includes at least one coil and at least one transistor serially connected to the coil. The drive member is provided with a plurality of output terminals adapted to output a driving signal to the transistor of the motor drive circuit. The PWM control circuit is in connection between the transistor of the motor drive circuit and the output terminal of the drive member, thereby turning the transistor on or off.

Abstract: A speed control circuit for a brushless dc motor includes a motor drive circuit, a drive member and a PWM control circuit. The motor drive circuit includes at least one coil and at least one transistor serially connected to the coil. The drive member is provided with a plurality of output terminals adapted to output a driving signal to the transistor of the motor drive circuit. The PWM control circuit is in connection between the transistor of the motor drive circuit and the output terminal of the drive member, thereby turning the transistor on or off.

Abstract: An electronically commutatable motor having field windings activatable in sequence with a commutation frequency via semiconductor output stages using control signals connectable and disconnectable from a direct voltage supply, the control signals being clocked using pulse width modulation. Noise generation from connection and disconnection of the current applied to field windings is minimized by flattening of the rising and/or falling edges of the current in the field windings. The pulse width ratio increases in the rising edges of the control signals from a low initial value to an operating value assigned to the setpoint as a function of a selected setpoint for the motor speed or output, and, in the falling edges of the control signals, the pulse width ratio starts from the existing operating value and is reduced to a lower final turn-off value as a function of the existing actual value of the speed or the output of the motor.

Abstract: A children's ride-on vehicle having an electronic speed controller adapted to regulate at least one of the timing and rate of application of a selected rotational input. The vehicle includes a body with a seat, a steering mechanism positioned for operation by a child to steer at least one of the vehicle's wheels, and a drive assembly with an actuator positioned for actuation by a child sitting on the seat to cause the driven rotation of at least one of the vehicle's wheels by a battery-powered motor assembly. In some embodiments, the drive assembly includes one or more user input devices that enable a child sitting on the seat to select at least one of the relative speed and direction of the vehicle. The drive assembly also includes an electronic speed controller that controls electronically the transmission of a selected rotational input to the vehicle's driven wheel assembly.

Abstract: A multi-mode motor controller architecture includes a motor, an integrated circuit controller, and an integrated circuit driver circuit. The integrated circuit controller includes a pulse generator, a DAC, an ADC, and a digital compensator circuit. The integrated circuit driver circuit is in communication with the controller and includes an error amplifier, first and second output amplifiers for driving the motor, and a sense amplifier. The motor controller architecture is configurable to operate in a linear mode, a pulsed mode, or a switchable linear/pulsed mode. The controller architecture can be implemented with external compensation circuitry, such as a resistor-capacitor circuit, or with the digital compensation circuitry located within the controller integrated circuit.

Abstract: The invention relates to a method for control of the speed of rotation of a separately excited direct current motor for model vehicles, the speed of rotation of the motor being controlled by means of a pulse sequence, the motor being alternately supplied with a supply voltage during a switch-on period and disconnected from the supply voltage during a switch-off period, the duration of the switch-off period being dependent on the deviation of an actual value from a set value for the speed of rotation of the motor. In order to further develop the method in such a way that the separately excited motor has a low noise output and stable control is possible over a wide range of speed of rotation, it is proposed that a pulse width modulated signal is provided, the pulse width of which is dependent on the average torque loading of the motor, and that the pulse width modulated signal is combined with the pulse sequence by an AND-operation.

Abstract: A motor control circuit for use in a motor circuit includes a varying duty cycle pulse width modulation circuit and a switch. The varying duty cycle pulse width modulation circuit is operable to generate a PWM signal having a varying duty cycle, wherein an average of said varying duty cycle corresponds to a desired motor speed. The switch has a control input operably coupled to the pulse width modulation circuit to receive the PWM signal therefrom. The switch further includes first and second terminals, the first terminal adapted to be coupled to a coil of the motor circuit, the switch operable to selectively electrically connect and disconnect the first and second terminals based in part on the PWM signal received by the control input.

Abstract: A method and circuit for operating a polyphase dc motor in which discontinuous sinusoidal drive voltages are applied to the windings of the motor in predetermined phases. The discontinuous portion of the sinusoid is timed with the bemf zero crossings. Bemf zero crossings are detected, and phases of the drive voltages are adjusted to have zero crossings substantially in the discontinuities of the drive voltages. The method and circuit result in motor operation with significantly reduced acoustic motor noise.

Abstract: A hand-off state determination section 73 estimates torque Th exerted on the steering handle by a driver. When the steering handle is in the hand-off state in which the torque is small, switching is effected to the side of compensator 75 having smaller gains set, so as to stabilize a steering control system.

Abstract: Apparatus providing a control and protection arrangement for walking/running exercise machines which is effective to provide protection against malfunction conditions which may be experienced by the exercise machines, to thereby protect users of the exercise machine against injuries. The present invention provides an efficient response time to motor speed variations to provide greater user safety.

Abstract: A control device for a DC motor driving a diaphragm pump including a pulse generating integral circuit and a variable voltage setting integral circuit. The variable voltage setting integral circuit sets a pulse-base voltage at a level such that the DC motor is not rotated when no pulse is applied, thereby a high voltage overshoot generated at the rising and the falling point of an electrical pulse is restricted. Discharge of the diaphragm pump is accurately regulated by means of modifying frequency, voltage, and duty ratio of the pulse.

Abstract: It is an object of the present invention to provide a steering control system which can be used with a plurality of control modes, thereby reducing the cost. A first control unit of an electric power-steering system detects a reference current i.sub.REF on the basis of a steering torque T detected by a steering torque detecting device S.sub.2 ; searches a gain K.sub.1 on the basis of a vehicle speed v detected by a vehicle speed detecting device, and carries out a feedback control, so that an actual current i of an electric motor detected by a current detecting device is equal to K.sub.1 .times.i.sub.REF. A second control unit added to the first control unit changes the characteristic of the electric power-steering system by changing the steering torque T and the vehicle speed v, to output the changed steering torque T and vehicle speed v to the first control unit.

Abstract: A remote-control vehicle includes a controller that produces a pulse-width modulated (PWM) motor control signal and a forward/reverse motor control signal in response to a transmitted digital signal specifying one of a multiplicity of speed control states, each of which has a direction and a PWM duty cycle associated therewith. A MOSFET switch turns on and off in response to the PWM signal to control the flow of current between a battery and a motor to thereby control the speed of the motor. A relay, coupled between the battery and the motor, switches in response to the forward/reverse signal to change the direction of current flow through the motor to thereby control the direction of the motor.

Abstract: A motor control apparatus for controlling a motor is provided. The motor has an output power stage and a relay allowing power to be connected to the output power stage. The apparatus comprises a microprocessor providing a PWM cycle delivered through a capacitor to a transistor. The microprocessor activates the transistor for a first predetermined amount of time during the PWM cycle causing the relay to actuate the output power stage thereby driving the motor. A detection mechanism within the microprocessor for detecting a fault in the main output transistor. The circuitry disengages the relay from the output power stage thereby causing the motor to cease being driven.

Abstract: A distributed power supply for a motor controller including electronic control circuits for controlling IGBT power transistor stages. The power supplies for the power transistors and gate drivers therefor are isolated from the power supplies for the electronic control circuits. Each of the gate drivers for the IGBT power transistor is supplied through a separate floating supply. Power supplies for the digital components and the analog components have separate ground return paths and are tied together at the supplies.

Abstract: An arrangement is disclosed for controlling fan motors in fan-powered terminal units which permit the air flow of the terminal units to be factory preset and reset using a voltmeter. The fan motor is responsive to the pulse width of pulses of a pulse width modulated signal to provide an air flow which is proportional to the pulse width. By adjusting the pulse width, the air flow may be set as desired. A pulse width modulated signal having pulses with a set amplitude and frequency is generated. The dc voltage of the pulse width modulated signal is measured using a voltmeter. As the pulses have a set amplitude and frequency, the pulse width of the pulses may be adjusted by controlling the dc voltage of the pulse width modulated signal. The fan motor is programmed to deliver the set air flow over a range of static pressures.