In a motor driving system, a motor driving system is provided which simplifies the system by ceasing ON/OFF control of a commercial driving command, and by performing commercial synchronous transfer and capture control based on a drive speed reference. A system controller performs synchronization control so as to make a drive output coincident with a phase/amplitude of a commercial AC power source when a rotation speed of a motor exceeds a drive speed reference n2, and when a prescribed requirement is satisfied, the commercial AC power source is synchronously transferred, and the motor is driven by the commercial AC power source. In addition, when the drive speed reference is set to n1, and a drive output side switch is closed, the drive output is connected to the commercial AC power source, and when a prescribed requirement is satisfied, the motor is started to be driven at a variable speed (t7), and thereby the synchronous capture is performed.

A system and method for estimating operating characteristics of an induction motor is disclosed. The system includes a motor control device that is electrically connectable between a motor and a power source. The motor control device includes a plurality of switching devices comprising at least one thyristor corresponding to a respective phase of the motor. The motor control device also includes a controller programmed to disconnect the power source from the motor for a predetermined time period following a first plurality of cycles of a mains phase voltage of the power source. The controller is further programmed to measure a back-emf voltage during the predetermined time period, estimate an operating characteristic of the motor from the measured back-emf voltage, and trigger the plurality of switching devices to reconnect the power source to the motor following estimation of the operating characteristic.

A system and method for estimating operating characteristics of an induction motor is disclosed. The system includes a motor control device that is electrically connectable between a motor and a power source. The motor control device includes a plurality of switching devices comprising at least one thyristor corresponding to a respective phase of the motor. The motor control device also includes a controller programmed to disconnect the power source from the motor for a predetermined time period following a first plurality of cycles of a mains phase voltage of the power source. The controller is further programmed to measure a back-emf voltage during the predetermined time period, estimate an operating characteristic of the motor from the measured back-emf voltage, and trigger the plurality of switching devices to reconnect the power source to the motor following estimation of the operating characteristic.

One embodiment describes an interlock for an electromechanical switching system, which includes a housing; a first camming lockout member disposed in the housing and that contacts an auxiliary operator of a first electromechanical switching device; a second camming lockout member disposed in the housing and that contacts an auxiliary operator of a second electromechanical switching device, which the first camming lockout members contacts the second camming lockout member when the first camming lockout member is moved to an actuated position by the first electromechanical switching device to prevent movement of the second camming lockout member to an actuated position.

One embodiment describes an interlock for an electromechanical switching system, which includes a housing; a first camming lockout member disposed in the housing and that contacts an auxiliary operator of a first electromechanical switching device; a second camming lockout member disposed in the housing and that contacts an auxiliary operator of a second electromechanical switching device, which the first camming lockout members contacts the second camming lockout member when the first camming lockout member is moved to an actuated position by the first electromechanical switching device to prevent movement of the second camming lockout member to an actuated position.

A capacitor is connected between the direct current voltage terminals. Switched terminals of a first switch and a second switch are coupled in series, between the direct current voltage terminals. An electric machine or generator has one or more windings and a first phase output terminal associated with the switched terminals. A first set of blocking diodes are cascaded in series and second set of blocking diodes are cascaded in series. A first voltage supply provides a first output voltage level and a second output level switchable to the first control terminal, where the first output level is distinct from the second output level. A second voltage supply provides the first output voltage level and the second output level switchable to the second control terminal.

A capacitor is connected between the direct current voltage terminals. Switched terminals of a first switch and a second switch are coupled in series, between the direct current voltage terminals. An electric machine or generator has one or more windings and a first phase output terminal associated with the switched terminals. A first set of blocking diodes are cascaded in series and second set of blocking diodes are cascaded in series. A first voltage supply provides a first output voltage level and a second output level switchable to the first control terminal, where the first output level is distinct from the second output level. A second voltage supply provides the first output voltage level and the second output level switchable to the second control terminal.

A rotor of line start permanent magnet synchronous motor is provided. The rotor includes bars of cage windings. The rotor includes an additional inductance coupled to the cage windings and located on a first end of the bars. The rotor includes an end ring located on a second end of the bars. The additional inductance provides a reactance to reduce a starting current during an asynchronous starting of the line start permanent magnet synchronous motor.

A controller and methods for hybrid operation control of an electric motor in an electric motor system are provided. The controller is configured to receive a speed command for operating the electric motor, measure available voltage on an inverter configured to provide conditioned AC voltage to the electric motor, and determine a winding phase angle difference based on the received speed command and the measured available inverter voltage. The controller is also configured to adjust a phase angle difference between winding voltage commands for the switches of the inverter using the determined winding phase angle difference, and apply the winding voltage commands including the adjusted phase angle difference to the inverter switches to control the electric motor.

One embodiment describes a switching device system, which includes a first single pole switching device that selectively connects and disconnects a first phase of electric power to a first winding of a three phase motor; a second single switching device that selectively connects and disconnects a second phase of electric power to a second winding of the three phase motor; in which the first and second single pole switching devices control temperature of the motor by, at a first time, connecting the first phase and the second phase electric power to the motor.