This method for controlling asynchronous electrical motors of a compressor system, comprises: —receiving an order to start a first asynchronous electrical motor and a second asynchronous electrical motor of a compressor system; —unloading said first and second motors, by operating respectively a first load control unit of the first motor and a second load control unit of the second motor, in order to reduce the mechanical load associated to said motors; —starting the first motor and, only once the first motor is running at nominal speed, starting the second motor, —loading both the first and second electrical motor only once the second motor has started and is running at nominal speed, by operating the first load control unit and the second load control unit, in order to increase the mechanical load associated to said motors.

This method for controlling asynchronous electrical motors of a compressor system, comprises: —receiving an order to start a first asynchronous electrical motor and a second asynchronous electrical motor of a compressor system; —unloading said first and second motors, by operating respectively a first load control unit of the first motor and a second load control unit of the second motor, in order to reduce the mechanical load associated to said motors; —starting the first motor and, only once the first motor is running at nominal speed, starting the second motor, —loading both the first and second electrical motor only once the second motor has started and is running at nominal speed, by operating the first load control unit and the second load control unit, in order to increase the mechanical load associated to said motors.

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).

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).

This method for controlling asynchronous electrical motors of a compressor system, comprises: receiving an order to start a first asynchronous electrical motor and a second asynchronous electrical motor of a compressor system; unloading said first and second motors, by operating respectively a first load control unit of the first motor and a second load control unit of the second motor, in order to reduce the mechanical load associated to said motors; starting the first motor and, only once the first motor is running at nominal speed, starting the second motor, loading both the first and second electrical motor only once the second motor has started and is running at nominal speed, by operating the first load control unit and the second load control unit, in order to increase the mechanical load associated to said motors.

This method for controlling asynchronous electrical motors of a compressor system, comprises: receiving an order to start a first asynchronous electrical motor and a second asynchronous electrical motor of a compressor system; unloading said first and second motors, by operating respectively a first load control unit of the first motor and a second load control unit of the second motor, in order to reduce the mechanical load associated to said motors; starting the first motor and, only once the first motor is running at nominal speed, starting the second motor, loading both the first and second electrical motor only once the second motor has started and is running at nominal speed, by operating the first load control unit and the second load control unit, in order to increase the mechanical load associated to said motors.

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 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).

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).

A multiple drive for a heavy load application includes a plurality of drive trains which are activated such that individual ones of the plurality of drive trains are successively activated automatically during startup of the heavy load application as part of a predefined activation strategy according to a predefined activation scheme and an activation sequence defined therein. In the event of a repeated start of the heavy-load application, a different activation scheme can be used for the activation.