A lifting device includes a motor designed as a three-phase asynchronous motor via which the lifting device can be driven to lift and lower a load, and includes a brake resistor via which a power output resulting from a motor generator operation that is carried out when lowering the load at a lowering speed can be converted into heat. The brake resistor is designed for a rated power which is less than the power resulting with a nominal load and a nominal speed. A method for operating a lifting device includes lowering a load at a lowering speed while taking into consideration at least one load capacity characteristic value of the brake resistor for the lowering speed, a threshold is set such that while lowering the load at the lowering speed corresponding to the threshold, the resulting power output is limited to the at least one load capacity characteristic value.

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.

The disclosure relates to a work machine, in particular a duty-cycle crawler crane, having an undercarriage which comprises a middle part and at least one crawler carrier which is connected to the middle part and comprises at least one electric traction drive, wherein at least one supply line runs from the middle part to the traction drive and is connected to the latter in a disconnectable manner via a first connection. According to the disclosure, the work machine comprises an electrical interlock loop, which is connected to the traction drive via the first connection, and a mating plug connector module, which is arranged on the undercarriage and has a first mating connection for connecting to the first connection of the supply line and is configured to bridge the interlock loop, which is interrupted by a disconnection from the traction drive, in a current-conducting manner.

An automatic method of power management for supplying power to a crane includes a main power source comprising a generating set having an optimum power range in which it delivers a main power and a rechargeable secondary power source configured to deliver a secondary power, has a charge level, and may be recharged by the main power source. The automatic method implements, depending on the power required for the operation of the crane and the charge level, one or more power management modes for which the crane receives power coming from the single main power source or from the two power sources, and such that the generating set operates for each of them in the optimum power range.

The present disclosure relates to an inverter provided in a hoist system, which includes a scale unit configured to control a size of a DC link voltage of the inverter, a proportional-integral (PI) controller configured to perform PI-control on an output of the scale unit and an output voltage of the inverter and outputting a control signal, a first calculating unit configured to sum a command frequency of the inverter and the control signal, and a voltage determining unit configured to determine an output voltage of the inverter from an output frequency of the first calculating unit.

A lifting device includes a motor designed as a three-phase asynchronous motor via which the lifting device can be driven to lift and lower a load, and includes a brake resistor via which a power output resulting from a motor generator operation that is carried out when lowering the load at a lowering speed can be converted into heat. The brake resistor is designed for a rated power which is less than the power resulting with a nominal load and a nominal speed. A method for operating a lifting device includes lowering a load at a lowering speed while taking into consideration at least one load capacity characteristic value of the brake resistor for the lowering speed, a threshold is set such that while lowering the load at the lowering speed corresponding to the threshold, the resulting power output is limited to the at least one load capacity characteristic value.

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.