A system in which the operation of an electric motor is controlled by electronically controlled switches. The system includes the motor having a run winding and a start winding, a heating component, and a motor control subsystem. A control unit closes a first switch to energize the run winding, closes a second switch to energize the start winding, determines based on an amplitude and a lag time of a current flowing through the motor whether the motor has started and is running normally, and if so, opens the second switch to de-energize the start winding and closes a third switch to activate the heating component. The control unit determines whether the motor has started and is running normally by comparing the real time amplitude and lag time of the current to a plurality of stored amplitudes and lag times associated with different operating conditions.

A system in which the operation of an electric motor is controlled by electronically controlled switches. The system includes the motor having a run winding and a start winding, a heating component, and a motor control subsystem. A control unit closes a first switch to energize the run winding, closes a second switch to energize the start winding, determines based on an amplitude and a lag time of a current flowing through the motor whether the motor has started and is running normally, and if so, opens the second switch to de-energize the start winding and closes a third switch to activate the heating component. The control unit determines whether the motor has started and is running normally by comparing the real time amplitude and lag time of the current to a plurality of stored amplitudes and lag times associated with different operating conditions.

According to one embodiment, a control system includes a chopper, a short-circuit unit, a voltage detector circuit, and a controller. The chopper reduces a direct current voltage between a converter connected to a stator in a wound induction machine and an inverter connected to a rotor in the wound induction machine. The short-circuit unit shorts a wire used for connection between the rotor and the inverter and the voltage detector circuit is to detect the direct current voltage. The controller causes driving the chopper and, at the same time, outputting from the inverter an alternating current over which a direct current component is superimposed when a voltage value exceeds a first predetermined value, and causes driving the short-circuit unit and, at the same time, halting the inverter when the voltage value exceeds a second predetermined value.

An aircraft includes a power source arranged to provide AC electrical power of varying frequency, and a brake cooling fan including an impeller which is driven by an electric motor powered by said AC electrical power for cooling brakes of the aircrafts wheels. The brake cooling fan has an operable mode when the frequency of said AC electrical power meets certain criteria indicating that the frequency of the AC power is suitable for powering the motor, and an inoperable mode to protect against unsuitable operation of the motor. The brake cooling fan may then be safely powered with AC power direct from a wild frequency power network on the aircraft without needing a power inverter or constant power supply generator.

An aircraft includes a power source arranged to provide AC electrical power of varying frequency, and a brake cooling fan including an impeller which is driven by an electric motor powered by said AC electrical power for cooling brakes of the aircrafts wheels. The brake cooling fan has an operable mode when the frequency of said AC electrical power meets certain criteria indicating that the frequency of the AC power is suitable for powering the motor, and an inoperable mode to protect against unsuitable operation of the motor. The brake cooling fan may then be safely powered with AC power direct from a wild frequency power network on the aircraft without needing a power inverter or constant power supply generator.

A system and method for controlling a speed of a permanent magnet AC motor (38) based on a delay angle of a triac-controlled AC voltage signal (66) from a triac (34). A simulated load (54) connected to the triac (34) enables a load current and creates the signal (66). A first detector (48) detects a zero-crossing point of the AC voltage signal, and a second detector (50) detects a subsequent turn-on instance of the triac (34). A speed command generator (52) measures an interval between the zero-crossing point and the subsequent turn-on instance, and converts the delay angle to a speed command for controlling the speed of the motor (38). The simulated load (54) may include resistors (70) having a resistance which causes the load current to be below a holding current rating of the triac (34), thereby causing the triac (34) to turn off after the interval has been measured.

The present disclosure provides a control system (100, 200, 300) for controlling a single phase induction motor (150, 250) with a main winding (151, 251) and with an auxiliary winding (152, 252), the control system (100, 200, 300) comprising a first bidirectional switching element (101) and a second bidirectional switching element (102), wherein the first bidirectional switching element (101) is arranged between a phase supply input (103, 203) of the single phase induction motor (150, 250) and the main winding (151, 251) and wherein the second bidirectional switching element (102) is arranged electrically parallel to the main winding (151, 251), a control unit (105, 205) coupled to the first bidirectional switching element (101) and the second bidirectional switching element (102), wherein the control unit (105, 205) is configured to control in an alternating manner during a positive half-wave of a supply voltage of the single phase induction motor (150, 250) the first bidirectional switching element (101) to provide a positive current to the main winding (151, 251) and the second bidirectional switching element (102) to provide a freewheeling current path for the positive current through the main winding (151, 251), and wherein the control unit (105, 205) is configured to control in an alternating manner during a negative half-wave of a supply voltage of the single phase induction motor (150, 250) the first bidirectional switching element (101) to provide a negative current to the main winding (151, 251) and the second bidirectional switching element (102) to provide a freewheeling current path for the negative current through the main winding (151, 251). Further, the present disclosure provides a respective control method.

The present disclosure provides a control system (100, 200, 300) for controlling a single phase induction motor (150, 250) with a main winding (151, 251) and with an auxiliary winding (152, 252), the control system (100, 200, 300) comprising a first bidirectional switching element (101) and a second bidirectional switching element (102), wherein the first bidirectional switching element (101) is arranged between a phase supply input (103, 203) of the single phase induction motor (150, 250) and the main winding (151, 251) and wherein the second bidirectional switching element (102) is arranged electrically parallel to the main winding (151, 251), a control unit (105, 205) coupled to the first bidirectional switching element (101) and the second bidirectional switching element (102), wherein the control unit (105, 205) is configured to control in an alternating manner during a positive half-wave of a supply voltage of the single phase induction motor (150, 250) the first bidirectional switching element (101) to provide a positive current to the main winding (151, 251) and the second bidirectional switching element (102) to provide a freewheeling current path for the positive current through the main winding (151, 251), and wherein the control unit (105, 205) is configured to control in an alternating manner during a negative half-wave of a supply voltage of the single phase induction motor (150, 250) the first bidirectional switching element (101) to provide a negative current to the main winding (151, 251) and the second bidirectional switching element (102) to provide a freewheeling current path for the negative current through the main winding (151, 251). Further, the present disclosure provides a respective control method.

A device (1) for starting a motor (4) for alternating current, in particular for a compressor (5), wherein the motor (4) has at least one feed line (3) for the electrical power supply. The device comprises an actuator element (10) for limiting the current in the feed line (3), a switching element (16) for bypassing the actuator element (10), a current-monitoring element (15) for monitoring the current in the feed line (3), and a controller (18) for controlling the switching element (16). The actuator element (10) comprises at least a first start-up element (11) and a second start-up element (12) as well as a switch-over element (14) for switching over between the at least first and second start-up elements (11, 12).

A device (1) for starting a motor (4) for alternating current, in particular for a compressor (5), wherein the motor (4) has at least one feed line (3) for the electrical power supply. The device comprises an actuator element (10) for limiting the current in the feed line (3), a switching element (16) for bypassing the actuator element (10), a current-monitoring element (15) for monitoring the current in the feed line (3), and a controller (18) for controlling the switching element (16). The actuator element (10) comprises at least a first start-up element (11) and a second start-up element (12) as well as a switch-over element (14) for switching over between the at least first and second start-up elements (11, 12).