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.

Disclosed are a variable power motor and an intelligent controller therefor. The motor includes a rotor, a stator, a housing, stator windings and terminals. The stator windings are formed by embedding the same stator core into multiple series windings. Various series nodes of the stator windings, each serving as a power supply terminal with different power, are respectively led out individually. The various series windings of the stator respectively control, by means of the intelligent controller, the switching on and off of multiple switching switches. The soft-start and soft-stop of the motor can be realized, and a load is automatically tracked to regulate the power of the winding during operation, so as to obtain a power-saving effect.

A motor starter includes: a motor circuit breaker which has an electronic tripping device; a contactor which is correspondingly interconnected to the motor circuit breaker for forming the motor starter; and at least one control line disposed between the motor circuit breaker and the contactor, via which control line a control signal, which is generated depending upon a switching signal for switching the contactor, is transmitted from the contactor to the electronic tripping device. The electronic tripping device generates a tripping signal for switching off a current flow across the switching contact or switching contacts of the motor circuit breaker, depending upon the control signal and current flow across one or more switching contacts of the motor circuit breaker.

A motor starter includes: a motor circuit breaker which has an electronic tripping device; a contactor which is correspondingly interconnected to the motor circuit breaker for forming the motor starter; and at least one control line disposed between the motor circuit breaker and the contactor, via which control line a control signal, which is generated depending upon a switching signal for switching the contactor, is transmitted from the contactor to the electronic tripping device. The electronic tripping device generates a tripping signal for switching off a current flow across the switching contact or switching contacts of the motor circuit breaker, depending upon the control signal and current flow across one or more switching contacts of the motor circuit breaker.

The present invention provides an improved hybrid motor starter that extends the expected life of the main motor contacts of a standard contactor by reducing arcing during opening and closing of the main motor contacts and permits the use of physically smaller solid state switching devices and secondary contacts that have electrical ratings significantly lower than the standard contactor. The use of smaller solid state switching device and secondary contacts that have lower electrical ratings is permitted by minimizing the time at which these devices are exposed to full motor currents.

The present invention provides an improved hybrid motor starter that extends the expected life of the main motor contacts of a standard contactor by reducing arcing during opening and closing of the main motor contacts and permits the use of physically smaller solid state switching devices and secondary contacts that have electrical ratings significantly lower than the standard contactor. The use of smaller solid state switching device and secondary contacts that have lower electrical ratings is permitted by minimizing the time at which these devices are exposed to full motor currents.

A motor starter for operating an electric motor connected to a multiphase power supply includes a semiconductor switch arranged in a current-carrying phase of the multiphase power supply, and an electromechanical switch arranged in parallel relation to the semiconductor switch in the current-carrying phase. The electromechanical switch includes a movable switching piece configured tiltable to reduce a current gradient in the semiconductor switch.

A method for starting an induction machine without residual flux includes: scanning a state of the induction machine with different stator frequencies by controlling a supply voltage applied to the induction machine; determining whether a slip value, being a difference between a rotor frequency and a stator frequency, is within a slip interval; and, when it has been determined that the slip value is in the slip interval, regulating the slip value towards zero and magnetising the machine to the required level.

A method for starting an induction machine without residual flux includes: scanning a state of the induction machine with different stator frequencies by controlling a supply voltage applied to the induction machine; determining whether a slip value, being a difference between a rotor frequency and a stator frequency, is within a slip interval; and, when it has been determined that the slip value is in the slip interval, regulating the slip value towards zero and magnetising the machine to the required level.

A switching device, for a wye-delta switch in a multiphase motor each phase having one motor winding having a connection pair and contact device (CD), has an electromagnetic drive for drive axle movement between three axial positions, the CD having first and second motor winding connection contacts (MWCC), phase connection contact (PCC), and movable contact bridge (MCB) coupled to the drive axle and movable thereby into the three positions. In position-1, axially between positions-2/3, the MCB is openno CC is connected to another CC by the MCB; in position-2, the MCB is in wye contact positionthe MCB connects the PCC to the first MWCC, and the second MWCC is connected to the second MWCC of all other CDs using the wye coupled to the drive axle; and in position-3, the MCB is in a delta contact positionthe MCB connects the FCC to the first and second MWCC.