Abstract: A dual motor arrangement includes a first motor M1, a first MOSFET Q1 constructed and arranged to control operation of the first motor, a second motor M2, a second MOSFET Q2 constructed and arranged to control operation of the second motor, an RFI filter structure L1, C_RFI, a freewheeling circuit L2, C2, and a controller S. The controller is constructed and arranged to provide a first PWM signal to the first MOSFET and a second PWM signal to the second MOSFET. The second PWM signal is in staggered time relation with respect to the first PWM signal. When one motor is in a freewheeling mode of operation for at least a portion of a time that the MOSFET, associated with the other motor, is on, freewheeling of the one motor decreases an amount of current drawn by the other motor during turn on of the other motor. The inductors L1, L2 can be coupled to define a transformer.

Abstract: A stator and armature assembly 12 is provided for a permanent magnet DC motor. The assembly includes an armature 13 having a lamination core 14 and windings 15, and a stator structure 16 associated with the armature. The armature is constructed and arranged to rotate with respect to the stator structure. The stator structure includes at least one permanent magnet 22 providing a certain flux, and at least one wound core structure 17 having a core 18 and a coil 19 wound about the core so as to define an alternate pole with respect to the permanent magnet. When current to the coil is controlled, flux of the stator structure 16 can be increased or decreased relative to the certain flux. In this way a motor can operate at different speeds.

Abstract: A closed-loop system 10 is provided for controlling a DC motor. The system includes a DC motor 12, a controller 18 associated with the motor and constructed and arranged to control operation of the motor, a voltage sensor 14 constructed and arranged to measure a voltage supplied to the motor, a speed sensor 16 associated with the motor and constructed and arranged to obtain a measured speed of the motor, and a conditioning circuit 21 constructed and arranged to receive a speed signal and condition the speed signal to provide to the controller, a nominal speed based on the voltage supplied to the motor, or nominal rate of acceleration or deceleration upon a change in the desired speed. The controller 18 is constructed and arranged to compare the measured speed with a certain speed, that is less than the nominal speed, at a voltage corresponding to a measured voltage, and if the measured speed is less than the certain speed, a fault condition is defined by the controller.

Abstract: A dual motor configuration 10 includes a primary brushless motor 18 electronically controlled to be driven at various speeds throughout a range of motor speeds. A secondary brush motor 24 electronically controlled be driven at various speeds throughout a range of motor 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, throughout the ranges of motor speeds, of the first and second motors can be selectively chosen.

Abstract: A stator and armature assembly 12 is provided for a permanent magnet DC motor. The assembly includes an armature 13 having a lamination core 14 and windings 15, and a stator structure 16 associated with the armature. The armature is constructed and arranged to rotate with respect to the stator structure. The stator structure includes at least one permanent magnet 22 providing a certain flux, and at least one wound core structure 17 having a core 18 and a coil 19 wound about the core so as to define an alternate pole with respect to the permanent magnet. When current to the coil is controlled, flux of the stator structure 16 can be increased or decreased relative to the certain flux. In this way a motor can operate at different speeds.

Abstract: A brush type DC motor 10 having an armature 15 and positive and negative power leads is provided. The motor includes an RFI choke 12 as a transformer in series with at least one of the positive and negative power leads to amplify current such that rotation of the armature 15 can be detected based on monitoring a voltage relating to the amplified current. Conditioning circuitry 14 is constructed and arranged to condition the voltage for detecting rotation of the armature.

Abstract: A cooling system includes multiple cooling fans, each driven by a corresponding fan motor controller. Each fan motor controller includes electronic commutation circuitry that is responsive to a modulated signal to control the speed of the associated motor and fan. The controller for one motor includes a microcontroller that receives a single control signal from an external control unit and translates that control signal into the modulated signals provided to all of the other motor controllers. In one embodiment, the microcontroller can adjust the duty cycle of the modulated control signals, and can stagger the on-off times of the signals to minimize conducted RFI emissions.

Abstract: A motor circuit includes a first brush-type motor, a second brush-type motor, a switch, and a pulse width modulation circuit. The first brush-type motor has a first voltage connection and a second voltage connection, the second voltage connection adapted to be coupled to a source of DC voltage. The second brush-type motor has a third voltage connection and a fourth voltage connection, the fourth voltage connection adapted to be coupled to the source of DC voltage. The switch has a control input, a first contact and a second contact, the first contact coupled to the source of DC voltage, and the second contact coupled to the first voltage connection and the third voltage connection. The switch is operable to selectively connect the first contact to the second contact based on a voltage at the control input. The pulse width modulation circuit is operable to generate a pulse width modulated (PWM) signal.

Abstract: A protection circuit for use in a power electronic circuit has a positive supply input, a negative supply input, and a snubber. The protection circuit includes a snubber bias lead, a positive voltage lead, a positive supply lead, a switch and a reverse polarity shut off circuit. The snubber bias lead is adapted to be coupled to obtain a bias voltage from the snubber of the power electronic circuit, the positive voltage lead is adapted to be coupled to a positive voltage lead of a power supply, and the positive supply lead is adapted to be coupled to the positive supply input of the power electronic circuit. The switch has a control input coupled to the snubber bias lead, a first terminal coupled to the positive voltage lead, and a second terminal coupled to the positive supply lead. The switch is operable to selectively allow current flow from the second terminal to the first terminal based at least in part on the bias voltage at said control input.

Abstract: A motor circuit includes a first brush-type motor, a second brush-type motor, a switch, and a pulse width modulation circuit. The first brush-type motor has a first voltage connection and a second voltage connection, the second voltage connection adapted to be coupled to a source of DC voltage. The second brush-type motor has a third voltage connection and a fourth voltage connection, the fourth voltage connection adapted to be coupled to the source of DC voltage. The switch has a control input, a first contact and a second contact, the first contact coupled to the source of DC voltage, and the second contact coupled to the first voltage connection and the third voltage connection. The switch is operable to selectively connect the first contact to the second contact based on a voltage at the control input. The pulse width modulation circuit is operable to generate a pulse width modulated (PWM) signal.

Abstract: A cooling system includes multiple cooling fans, each driven by a corresponding fan motor controller. Each fan motor controller includes electronic commutation circuitry that is responsive to a modulated signal to control the speed of the associated motor and fan. The controller for one motor includes a microcontroller that receives a single control signal from an external control unit and translates that control signal into the modulated signals provided to all of the other motor controllers. In one embodiment, the microcontroller can adjust the duty cycle of the modulated control signals, and can stagger the on-off times of the signals to minimize conducted RFI emissions.

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 control system (100) for a five-phase brushless DC motor (102) including a stator having five windings and a rotor (116) mounted for rotation relative to the windings (114). The windings (114) are adapted to be electronically commutated in response to the rotary position of the rotor (116). The control system (100) includes a sensing circuit (106) to sense the rotary position of the rotor (116) using an optical or magnetic sensor or the back electromotive force voltages in the windings (114). Electronic switches (112) control the flow of current through the windings (114) in response to control signals generated by a control circuit (110) in response to the rotary position of the rotor (116). The control circuit (110) includes start-up logic to start the motor (102).

Abstract: A protection system for an electric motor is disclosed. The system is adapted for providing protection to the motor in the event of a stall or reduced-speed condition. The system includes a sensor providing a first signal representative of the speed of the motor, a detection circuit receiving the first signal and providing a second signal indicative of whether the motor is in a stall or reduced-speed condition, and a switching circuit receiving the second signal and interrupting power supply to the motor when the second signal indicates that the motor is in the stall or reduced-speed condition.