An induction machine includes a stator and a rotor, wherein a stator winding is arranged within the stator, a control device controls a converter such that the converter connects the stator winding to a power-supply network such that a stator current flows within the stator winding, and the stator current has a field-forming current component and a torque-forming current component, where the control device controls the converter such that, during load periods, a torque acts between the stator and the rotor, controls the converter during periods of rest such that a torque acts between the stator and the rotor, controls the converter at least at the beginning of the periods of rest such that the field-forming current component has a nominal value, and controls the converter during the load periods such that the field-forming current component has a lower value than the nominal value.

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 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 method identifies magnetic saturation parameters of an asynchronous electric motor. The method consists in a monitoring and identification sequence including one or several iterations. The method includes applying at the input of the control law of a reference voltage or a reference flux trajectory or a reference range in order to obtain a magnetization current, building a real profile of magnetic saturation including estimate magnetization flux and measures magnetization current, and determining magnetic saturation parameters corresponding to the real profile already obtained.

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 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.

An arc-free phase control circuit for an AC motor that brings about an energy saving effect according to a load change and operates efficiently in terms of cost reduction while securing electrical stability by virtue of an overload protection function. The circuit includes a first relay, a TRIAC, a second relay, a voltage sensing unit, a current sensing unit, a speed voltage sensing unit, a zero-cross point detection unit, and a controller.

Various embodiments include determining an alternating current (AC) voltage and frequency of a supply voltage coupled to a circuit input. The circuit includes a soft starter circuit that is coupled between the circuit input and a first side of an AC motor. A stator winding configuration of the AC motor is determined. A control transformer is configured in response to the AC voltage and frequency, wherein the control transformer is coupled to the circuit input. A jumper device is configured on a second side of the AC motor in response to the stator winding configuration of the AC motor.

Various embodiments include determining an alternating current (AC) voltage and frequency of a supply voltage coupled to a circuit input. The circuit includes a soft starter circuit that is coupled between the circuit input and a first side of an AC motor. A stator winding configuration of the AC motor is determined. A control transformer is configured in response to the AC voltage and frequency, wherein the control transformer is coupled to the circuit input. A jumper device is configured on a second side of the AC motor in response to the stator winding configuration of the AC motor.

The present invention provides a variable speed accelerator including an electric driving device which is configured to generate a rotational driving force and a transmission device which is configured to change speed of the rotational driving force generated by the electric driving device and transmits the changed rotational driving force to a driving target. The transmission device includes a sun gear; a planetary gear which is configured to mesh with the sun gear; an internal gear which is configured to mesh with the planetary gear; a planetary gear carrier which has a planetary gear carrier shaft; and an internal gear carrier which has an internal gear carrier shaft. A sun gear shaft forms an output shaft which is connected to the driving target. The internal gear carrier shaft forms a constant-speed input shaft. The planetary gear carrier shaft forms a variable-speed input shaft. The electric driving device includes a constant-speed motor having a constant-speed rotor which is configured to rotate the constant-speed input shaft of the transmission device in a first direction, and a variable-speed motor which has a variable-speed rotor connected to the variable-speed input shaft of the transmission device, having a cylindrical shape centered on the axis and having the constant-speed input shaft inserted through a shaft insertion hole passing therethrough in the axial direction, and which is configured to rotate the output shaft at a maximum rotation rate by rotating the variable-speed rotor at a maximum rotation rate in a second direction opposite to the first direction. The variable speed accelerator further includes a power source line which connects the variable-speed motor with an AC power source so that the variable-speed motor rotates in the second direction, a rotation rate controller which is provided on the power source line and controls the rotation rate of the variable-speed motor, a first switch which is provided on the power source line, a bypass power source line which connects the variable-speed motor with the AC power source so that the variable-speed motor rotates in the first direction, and a second switch which is provided on the bypass line.