In a method for monitoring the operation of an electric motor and a lifting mechanism, the motor current is acquired, and the electric motor has, for example, an electromagnetically actuable brake, e.g., a holding brake. In the method, a pre-magnetization is performed when the electric motor is switched on, the characteristic of the acquired values of the motor current is monitored for an exceeding of a permissible measure of deviation from a setpoint characteristic, and a brake of the electric motor is activated, e.g., remains applied.

In a method for monitoring the operation of an electric motor and a lifting mechanism, the motor current is acquired, and the electric motor has, for example, an electromagnetically actuable brake, e.g., a holding brake. In the method, a pre-magnetization is performed when the electric motor is switched on, the characteristic of the acquired values of the motor current is monitored for an exceeding of a permissible measure of deviation from a setpoint characteristic, and a brake of the electric motor is activated, e.g., remains applied.

A motor drive apparatus that can continue operation within the upper limit of system control even if a voltage drop of an AC power source occurs during operation of a motor used for a hoist or a crane is provided. The inverter control unit of the motor drive apparatus includes a speed reference setting means for setting the rotation speed of the motor, means for detecting a speed deviation between the output of the rotation speed detection means for detecting the rotation speed of the motor and the output of the speed reference setting means, means for controlling the output current of the inverter according to the output of the speed deviation. The speed reference setting means includes a correction circuit for correcting an external speed command given from outside. The correction circuit corrects the external speed command according to a deviation between a detection value of a DC voltage and a first reference value when a voltage drop signal is received from the voltage drop detection means, and makes the corrected speed command as the output of the speed reference setting means.

A motor drive apparatus that can continue operation within the upper limit of system control even if a voltage drop of an AC power source occurs during operation of a motor used for a hoist or a crane is provided. The inverter control unit of the motor drive apparatus includes a speed reference setting means for setting the rotation speed of the motor, means for detecting a speed deviation between the output of the rotation speed detection means for detecting the rotation speed of the motor and the output of the speed reference setting means, means for controlling the output current of the inverter according to the output of the speed deviation. The speed reference setting means includes a correction circuit for correcting an external speed command given from outside. The correction circuit corrects the external speed command according to a deviation between a detection value of a DC voltage and a first reference value when a voltage drop signal is received from the voltage drop detection means, and makes the corrected speed command as the output of the speed reference setting means.

In a method for monitoring the operation of an electric motor and a lifting mechanism, the motor current is acquired, and the electric motor has, for example, an electromagnetically actuable brake, e.g., a holding brake. In the method, a pre-magnetization is performed when the electric motor is switched on, the characteristic of the acquired values of the motor current is monitored for an exceeding of a permissible measure of deviation from a setpoint characteristic, and a brake of the electric motor is activated, e.g., remains applied.

In a method for monitoring the operation of an electric motor and a lifting mechanism, the motor current is acquired, and the electric motor has, for example, an electromagnetically actuable brake, e.g., a holding brake. In the method, a pre-magnetization is performed when the electric motor is switched on, the characteristic of the acquired values of the motor current is monitored for an exceeding of a permissible measure of deviation from a setpoint characteristic, and a brake of the electric motor is activated, e.g., remains applied.

An allocation method for allocating an available maximum power from at least one power supply source to electrical equipment of a crane, in which the electrical equipment are powered with the available maximum power, includes selecting between: a raw mode in which the available maximum power is allocated over predefined actuation equipment and on accessory equipment predefined among the electrical equipment, the actuation equipment being defined according to a configuration of the crane, and an optimized mode in which the available maximum power is allocated over the predefined actuation equipment, and also over the accessory equipment but according to the cut-off conditions of the accessory equipment, so that according to the cut-off conditions the actuation equipment are powered or not.

An allocation method for allocating an available maximum power from at least one power supply source to electrical equipment of a crane, in which the electrical equipment are powered with the available maximum power, includes selecting between: a raw mode in which the available maximum power is allocated over predefined actuation equipment and on accessory equipment predefined among the electrical equipment, the actuation equipment being defined according to a configuration of the crane, and an optimized mode in which the available maximum power is allocated over the predefined actuation equipment, and also over the accessory equipment but according to the cut-off conditions of the accessory equipment, so that according to the cut-off conditions the actuation equipment are powered or not.

A method and system for controlling an actuator, in particular an actuator of a winch, a hoist or a crane, wherein the actuator is controlled using a fail-safe control unit. In order to improve a corresponding method, according to the invention, set point values are calculated in the fail-safe control unit, on the basis of which values the actuator is controlled.

A motor drive apparatus that can continue operation within the upper limit of system control even if a voltage drop of an AC power source occurs during operation of a motor used for a hoist or a crane is provided. The inverter control unit of the motor drive apparatus includes a speed reference setting means for setting the rotation speed of the motor, means for detecting a speed deviation between the output of the rotation speed detection means for detecting the rotation speed of the motor and the output of the speed reference setting means, means for controlling the output current of the inverter according to the output of the speed deviation. The speed reference setting means includes a correction circuit for correcting an external speed command given from outside. The correction circuit corrects the external speed command according to a deviation between a detection value of a DC voltage and a first reference value when a voltage drop signal is received from the voltage drop detection means, and makes the corrected speed command as the output of the speed reference setting means.