A vehicle includes first and second electric machines constrained to rotate in unison and configured to power a common axle. A controller is programmed to, in response to activation of the vehicle, select one of the first and second speed sensors as a representative speed sensor, and, in response to the electric machines being in speed control, command speeds to the first and second electric machines based on a difference between a target speed of the electric machines and a measured speed of the representative speed sensor.

A starting method of a variable speed accelerator, which includes an electric device for generating rotational driving force and a transmission device for changing a speed of the rotational driving force generated by the electric device and transmits the changed rotational driving force to an object to be driven, the starting method includes: a constant speed electric motor starting step of starting a constant speed electric motor and gradually increasing a number of rotations in a first direction of a constant speed rotor and an internal gear; and a generator mode operating step of operating a variable speed electric motor in a generator mode and rotating a planetary gear carrier in the first direction, wherein the transmission device is a planetary gear transmission device, and wherein the electric device comprises: the constant speed electric motor.

A starting method of a variable speed accelerator, which includes an electric device for generating rotational driving force and a transmission device for changing a speed of the rotational driving force generated by the electric device and transmits the changed rotational driving force to an object to be driven, the starting method includes: a constant speed electric motor starting step of starting a constant speed electric motor and gradually increasing a number of rotations in a first direction of a constant speed rotor and an internal gear; and a generator mode operating step of operating a variable speed electric motor in a generator mode and rotating a planetary gear carrier in the first direction, wherein the transmission device is a planetary gear transmission device, and wherein the electric device comprises: the constant speed electric motor.

A rotational driving force imparting device includes an electric motor device and a planetary gear transmission device. Among a sun gear shaft of a planetary gear transmission device, a planetary gear carrier shaft, and an internal gear carrier shaft, one shaft forms an output shaft, another shaft forms a constant speed input shaft, and the other shaft forms a variable speed input shaft. The electric motor device includes a constant speed motor including a constant speed rotor that rotates about a shaft line and is connected to a constant speed input shaft, and a variable speed motor including a variable speed rotor that rotates about the shaft line and is connected to a variable speed input shaft. A shaft insertion hole forming a cylindrical shape about the shaft line and penetrating in the axial direction is formed in the variable speed rotor, and the constant speed rotor is inserted into the shaft insertion hole.

A rotational driving force imparting device includes an electric motor device and a planetary gear transmission device. Among a sun gear shaft of a planetary gear transmission device, a planetary gear carrier shaft, and an internal gear carrier shaft, one shaft forms an output shaft, another shaft forms a constant speed input shaft, and the other shaft forms a variable speed input shaft. The electric motor device includes a constant speed motor including a constant speed rotor that rotates about a shaft line and is connected to a constant speed input shaft, and a variable speed motor including a variable speed rotor that rotates about the shaft line and is connected to a variable speed input shaft. A shaft insertion hole forming a cylindrical shape about the shaft line and penetrating in the axial direction is formed in the variable speed rotor, and the constant speed rotor is inserted into the shaft insertion hole.

A system for a mineral extraction system includes a shaft rotatably supported on a platform, a first motor having a first output shaft that is coupled to a first end portion of the shaft to drive rotation of the shaft, and a second motor having a second output shaft that is coupled to a second end portion of the shaft to drive rotation of the shaft. The system is devoid of a transmission between the first motor and the shaft.

A driving apparatus allowing two motors to drive a same driving shaft is provided. When a voltage command value is less than a predetermined threshold, a control unit outputs driving command values based on one control pattern such that a direction of a torque of one of the motors becomes different from a driving direction of the driving shaft. Also, when the voltage command value becomes greater than or equal to the predetermined threshold, the control unit outputs the driving command values based on another control pattern, such that the direction of the torque of the one of the motors becomes the same as the driving direction of the driving shaft when the voltage command value is greater than or equal to the predetermined threshold, and does not become different from the driving direction of the driving shaft when the voltage command value drops below the predetermined threshold.

In a method for actuating a motor for starting up a mill containing material to be ground, the motor for triggering sedimentation of the material to be ground in the mill is initially fed by a first inverter. The motor is subsequently disconnected from the first inverter, and in a further step the motor is connected to a first supply which has a first supply voltage. The maximum output voltage of the first inverter is lower than the first supply voltage.

In a method for actuating a motor for starting up a mill containing material to be ground, the motor for triggering sedimentation of the material to be ground in the mill is initially fed by a first inverter. The motor is subsequently disconnected from the first inverter, and in a further step the motor is connected to a first supply which has a first supply voltage. The maximum output voltage of the first inverter is lower than the first supply voltage.

A dual actuated power pack (300) comprises a battery (104) and first (101) and second (102) electric motors, as well as a power generator (103). The first electric motor (101) is powered by the battery (104) and the second electric motor (102) by a grid (106). The first and second electric motors (101, 102) are mechanically coupled (108) with each other so that when said second electric motor (102) is powered, said second electric motor (102) actuates (109) said power generator (103) and said first electric motor (101) at the same time, whereupon the first electric motor (101) functions as a hi-power battery charger and recharge the battery (104) when said second electric motor (102) actuates (109) the power generator (103). When the second electric motor is not used, the first electric motor (101) is powered (104, 105), and the power generator (103) is actuated (108) by said first electric motor (101).