Cable excavator with an electric drive

Abstract

The invention relates to a cable excavator comprising a moveable undercarriage, a superstructure rotatably mounted on the undercarriage, at least one electric drive for moving a component of the cable excavator, a control unit connected to the electric drive and a detection unit connected to the control unit for detecting a variable relating to the electric drive or to the component to be moved. The electric drive comprises an electric motor and a frequency converter, with which an adjustable alternating voltage can be provided to the electric motor. According to the invention, the control unit is designed to receive an actual value of the detected variable from the detection unit and to compare it with a target value dependent on an input signal, to control the frequency converter depending on this target / actual value comparison and to automatically take an action in the event of a defined deviation of the actual value from the target value.

Description

[0001] Cable excavator with an electric drive

[0002] The present invention relates to a cable excavator according to the preamble of claim 1.

[0003] In recent years, the trend has increasingly shifted toward the electrification of construction machinery in order to reduce CO2 emissions and increase energy security. As part of this electrification, the previously hydraulic drives of various systems, such as rotary drives for slewing gear or cable winches for hoists, as well as the travel drives themselves, have increasingly been replaced with corresponding electric drives. In addition to the advantages mentioned above, this also brings with it a number of problems. It is therefore essential to ensure that the corresponding drives are operated safely and that the systems are controlled safely.

[0004] In existing hydraulic systems, the components are driven by hydraulic motors, which in turn are supplied with energy by hydraulic pumps. The hydraulic components are controlled via electromechanical components (valves), with the electrical signals for controlling the electromechanical components being generated by the construction machine's control system (control computer, CAN modules, AD converters, etc.). The components of the hydraulic systems are selected in accordance with applicable laws and standards (e.g., Machinery Directive, EN 13849, product standards e.g., EN 13000, EN 474-12, etc.), i.e., the mechanical and electronic components used meet the required safety criteria such as MTTFd (Mean Time to Failure dangerous), B10d (Number of switching cycles until dangerous failure), PFH (Probability of a Dangerous Failure per Hour), DC (Diagnostic Coverage), etc.

[0005] In electrified construction machines such as duty cycle excavators, especially fully electrified machines, the main systems such as slewing gear, hoisting gear, travel drives, etc. do not have hydraulic drives or any of the aforementioned components and valves, so operational safety must be ensured based on the electrical components of the electric drives. If one of these drives malfunctions during operation, this can have fatal consequences, for example the duty cycle excavator tipping over due to a malfunction of the travel drive, a collision between the boom and the environment due to a malfunction of the slewing gear, or the lifting load falling due to a malfunction of the hoist winch. Based on these assessments, measures must be taken to ensure the safe operation of all electrically driven systems.

[0006] The present invention is therefore based on the object of ensuring safe operation of a rope excavator with electrically driven works.

[0007] According to the invention, this object is achieved by a cable excavator having the features of claim 1. Advantageous embodiments of the invention emerge from the subclaims and the following description.

[0008] Accordingly, a cable excavator is proposed which has an undercarriage, an uppercarriage rotatably mounted on the undercarriage, at least one electric drive for driving a mechanism, i.e. for moving a movable component of the cable excavator, a controller connected to the electric drive, and a detection unit connected to the controller for detecting a variable relating to the electric drive or the associated mechanism or the component to be moved. The electric drive comprises an electric motor and a frequency converter, by means of which an adjustable alternating voltage can be provided to the electric motor. In particular, the frequency of the alternating voltage provided to the electric motor can be varied by means of the frequency converter.

[0009] The quantity measured by the detection unit can be, for example, a position, a location, a speed, an acceleration, a force or a torque, or a rotational speed. This can relate to the component to be moved itself or to a moving (particularly rotating) component of the associated electrical drive (e.g., a rotational speed or a torque of an electric motor). In a hoist, the moving component can be a cable winch; in a slewing gear, for example, it can be a bearing part of a slewing bearing or the superstructure itself.

[0010] The term undercarriage is to be interpreted broadly in this context and can refer to a stationary or non-mobile structure (such as a platform anchored in the ground, a floating platform, a base column or the like) or a mobile undercarriage (e.g. with a tracked or wheeled undercarriage).

[0011] According to the invention, the controller is configured to receive a currently detected value of the monitored variable from the detection unit as an actual value and to compare it with a target value that depends on an input signal received by the controller. In particular, the controller determines the target value for the target-actual comparison from at least one input signal.

[0012] According to the invention, the controller is further configured to regulate the frequency converter depending on this target-actual comparison. In particular, the controller can influence the operation of the electric motor via appropriate control of the frequency converter and regulate it depending on the target-actual comparison. The frequency converter thus functions, in particular, as an actuator for controlling the electric drive or the corresponding mechanism of the cable excavator. The controller is further configured to automatically take action upon detection of a defined deviation of the actual value from the target value.In other words, the control system intervenes automatically (this does not necessarily have to mean an intervention in the control of the electric drive or in the operation of the cable excavator, but could, for example, simply be limited to issuing a warning to an operator) if the actual value deviates too significantly from the corresponding target value.

[0013] This makes it possible to monitor the operation of at least one of the rope excavator's electric drives and automatically issue warnings and / or initiate countermeasures if certain deviation limits are exceeded. This effectively prevents malfunctions, enabling the safe operation of a partially or fully electrified rope excavator.

[0014] The control can also take place within the frequency converter, meaning the control or part of the control can be part of the frequency converter. Alternatively, the control can comprise one or more control units connected to the frequency converter.

[0015] In one possible embodiment, the controller is configured to take action if a deviation between an actual torque and a target torque of the electric motor, or a variable derived therefrom, exceeds a limit value. This limit value applies to the respective plant or electric drive and may differ from limit values ​​for other plants or electric drives. The limit value may be fixed or constant. Alternatively, the limit value may be variable or changeable and depend, for example, on an operating state of the electric motor (e.g., the speed and / or torque of the electric motor or an applied load).

[0016] In a further possible embodiment, the controller is configured to take action if a deviation between an actual speed and a target speed of the electric motor, or a variable derived therefrom, exceeds a limit value. This limit value applies to the respective plant or electric drive and may differ from limit values ​​for other plants or electric drives. The limit value may be fixed or constant. Alternatively, the limit value may be variable or changeable and depend, for example, on an operating state of the electric motor (e.g., the speed and / or torque of the electric motor or an applied load).

[0017] It can be provided that only one torque (or a variable derived therefrom), only one speed (or a variable derived therefrom) or a combination or superposition of a torque and a speed (or corresponding derived variables) are used as target and actual variables for a specific electric drive.

[0018] If multiple electric drives are planned, the target values ​​and / or target variables of the various electric drives may differ from one another. For example, a torque (or a variable derived from it) could be used as the target and actual variables for a first electric drive, while for a second electric drive the target and actual variables represent a speed (or a variable derived from it). It is also conceivable that the same variables are used as target and actual variables for some or all electric drives. Even if the same variables (e.g. a torque) are considered for different electric drives, the target values ​​of this variable may differ from drive to drive (but may also be the same for several drives).

[0019] The same applies to the corresponding limit values, which determine for the respective electric drives when a deviation is too great and when appropriate action must be taken. The limit values ​​can be identical for some or all electric drives. However, individual fixed or variable limit values ​​can also be used for each electric drive. This depends in particular on the design of the respective drive or mechanism. In a further possible embodiment, it is provided that the undercarriage comprises an electrically operated chassis, in particular an electrically driven crawler chassis, and at least one electric drive controllable by the controller is an electric travel drive. In this case, the controller is preferably set up to take action if a deviation between the actual and target value exceeds a specified factor of a speed related to a maximum travel speed (e.g.if the deviation is more than 10% of the speed at maximum driving speed, although any other factor can of course be used instead of the 10% given as an example).

[0020] In a further possible embodiment, it is provided that the uppercarriage is rotatably connected to the undercarriage via a slewing gear, and at least one electric drive that can be controlled by the controller is a rotary drive of the slewing gear. The uppercarriage can be rotated by means of the slewing gear, in particular about a vertical axis of rotation, preferably by 360°. The controller is preferably configured to take action if a deviation between the actual and target values ​​exceeds a specified factor of a maximum permissible drive torque (e.g. 10% of the maximum permissible drive torque, whereby any other factor can be used instead of the 10% mentioned as an example) and / or a specified factor of a maximum permissible drive speed (e.g. 10% of the maximum permissible drive speed, whereby any other factor can be used here instead of the 10% mentioned as an example).

[0021] In a further possible embodiment, the cable excavator comprises a cable winch, in particular a hoisting cable winch or a retracting winch arranged on the superstructure, wherein at least one electric drive controllable by the controller is a drive for the cable winch or a winch drive. The controller is preferably configured to take action if a deviation between the actual and target value exceeds a specified factor of a maximum winch speed or rotational speed (e.g., if the deviation is more than 10% of the maximum winch speed, wherein any other factor can be used instead of the 10% mentioned as an example).

[0022] In another possible embodiment, the cable excavator comprises at least two electric drives for moving at least two different components or for operating at least two of the cable excavator's systems. Different limit values ​​are defined for at least two electric drives to determine a defined deviation to be observed. The limit values ​​can be constant or variable (e.g., depending on the operating state of the drive). The controller can be configured to use a different fixed or variable limit value for each electric drive (or at least for some of the electric drives).

[0023] In another possible embodiment, all rotary drives of the cable excavator are designed as electric drives, which can be controlled by the controller in one of the ways described above. These can, for example, be drives for one or more slewing gears, one or more hoisting gears, and / or a chassis. Preferably, the cable excavator is fully electrically operated, i.e., it does not have any hydraulic actuators and / or hydraulic motors to drive its gears.

[0024] In a further possible embodiment, it is provided that the target value supplied to the target-actual comparison is a torque, a speed or a combination of torque and speed.

[0025] In a further possible embodiment, the controller comprises a control module and a control module. These modules can be pure software components that are executed on a common control unit or on different control units. However, the control and control modules can also represent separate, interconnected control units (i.e., each comprise a CPU, a data memory, etc.). The control module is configured to determine a target value for the control module on the basis of at least one received input signal and to provide this target value to the control module. The control module is configured to receive an actual value, which relates to at least one electric drive of the cable excavator, from the recording unit and to compare this actual value with the target value specified by the control module.The control module therefore carries out the actual target-actual comparison and is preferably set up to control the frequency converter of the relevant electric drive depending on the target-actual comparison.

[0026] The control module can be part of the frequency converter or integrated into the frequency converter. In this case, the actual control (e.g., including adjusting the frequency and / or current for the electric motor) takes place in the frequency converter, and the control module only monitors the control by means of a target-actual comparison.

[0027] A common control module and / or a common regulation module can be provided for each drive of the cable excavator controlled according to the invention. Alternatively, separate regulation modules and, if necessary, separate control modules can be used for some or all drives.

[0028] In a further possible embodiment, the cable excavator comprises an input unit which is connected to the controller and is designed to send an input signal to the controller depending on a user input. The input unit can be, for example, a master switch, a keypad or a touchscreen. The input unit can be provided on the cable excavator, in particular in a driver's cab of the cable excavator, or on a mobile device such as a mobile control unit or a tablet computer. Multiple input units can be provided. The controller is designed to determine a target value for the target-actual comparison for at least one electric drive depending on the input signal.In a further possible embodiment, the cable excavator comprises a second detection unit connected to the controller, by means of which at least one operating parameter of the cable excavator, a variable relating to the position or movement of a movable component of the cable excavator, and / or an environmental parameter can be detected and provided as an input signal to the controller. Thus, the determination of the target value for the control of at least one electric drive depends entirely or partially on the sensor data of the second detection unit. The controller is configured to determine a target value for the target-actual comparison of at least one electric drive depending on the input signal.

[0029] For one or more electric drives, the controller may use multiple input signals to determine the respective target value, for example a combination of at least one input signal based on a user input and at least one input signal based on data from a second acquisition unit.

[0030] In another possible embodiment, the detection unit comprises at least one sensor. The detection unit can, for example, comprise at least one speed sensor and / or at least one torque sensor, such as a torque flange, and / or at least one load cell, depending on where the respective sensors are arranged on the associated electric drives and / or the mechanisms or movable components. Different sensors and / or different sensor arrangements can be used for different electric drives or mechanisms.

[0031] In another possible embodiment, at least one sensor is arranged on the electric motor of an electric drive, and / or at least one sensor is arranged on a frequency converter of an electric drive, and / or at least one sensor is arranged on a component of the cable excavator that can be moved by an electric drive, and / or at least one sensor is arranged on an interface between an electric motor and a movable component of the cable excavator. The type, number, and arrangement of the sensors can vary from drive to drive or from plant to plant.

[0032] In a further possible embodiment, it is provided that the measure comprises the output of a warning signal, in particular an acoustic and / or a visual warning signal, for example in a driver's cab of the cable excavator and / or on a mobile device. Alternatively or additionally, the measure can comprise an intervention in the control system of the cable excavator, in particular a limitation or stopping of a current movement of the cable excavator, in the case of a hoist winch, for example, the triggering of a category 0 stop (i.e. no more torque is generated at the electric motor) and the subsequent closing of a holding brake, which stops the rotation of the winch and thus holds the load on the winch.

[0033] For different electric drives, different measures can be taken, adapted to the respective plant or component.

[0034] In principle, the monitoring and control of electric drives or mechanisms described here is also suitable for other construction machinery, for example, mobile construction machinery such as dump trucks, crawler cranes, mobile cranes, hydraulic excavators, wheel loaders, truck-mounted concrete pumps, truck mixers, or civil engineering machinery such as rotary drilling rigs, trench cutters or grabs, hydraulic hammers, or vibratory pile drivers, as well as for stationary construction machinery such as tower cranes or transport devices. In these cases, corresponding electric drives can be used to control or move slewing gear, cable winches, carriages, or any other moving components.

[0035] Further features, details, and advantages of the invention will become apparent from the following exemplary embodiments explained with reference to the figures. They show:

[0036] Figure 1: a schematic representation of the electric drive of the cable excavator according to the invention according to a first embodiment; Figure 2: a schematic representation of the electric drive of the cable excavator according to the invention according to a second embodiment;

[0037] Figure 3: a schematic representation of the electric drive of the cable excavator according to the invention according to a third embodiment;

[0038] Figure 4: a schematic representation of the electric drive of the cable excavator according to the invention according to a fourth embodiment; and

[0039] Figure 5: a graphical representation of the time course of target and actual

[0040] Value according to an embodiment.

[0041] Figures 1-4 each show a schematic representation of an electrically operated unit of the cable excavator according to the invention according to four exemplary embodiments, wherein the components of the electric drive 10, together with the controller 20 and the component 50 of the unit to be moved or driven by the electric drive 10, are schematically represented as boxes. Identical components have the same reference numerals in Figures 1-4.

[0042] The electric drive 10 comprises an electric motor 12, which is connected to the component 50 to be moved via an interface 13, in particular a mechanical connection, which may include, for example, a mechanical gear in addition to an output of the electric motor 12. The component 50 may be connected to further elements or components that are not shown here (for example, the component shown as box 50 may be a hoist cable winch, which in turn carries a hoist cable, which in turn may be connected to a hook block).

[0043] The electric motor 12 is a three-phase machine in which the rotary movement is caused by a rotating field or by an alternating voltage. This alternating voltage is generated by a frequency converter 14, wherein the frequency and, if applicable, also the amplitude of the alternating voltage can be varied by the frequency converter 14, so that the electric motor 12 can be operated according to certain specifications and the component 50 can be moved in a required manner. The frequency converter 14 generates the alternating field or the alternating voltage according to a target value 21, which is provided by a controller 20. Although the controller 20 is shown as a single box in Figures 1-4, it can comprise several control units that are connected to one another and together form a controller 20. Alternatively, the controller 20 can be implemented by a single control unit. The power supply to the electric motor 12 by the frequency converter 14, i.e.the provision of the said alternating field is illustrated in Figures 1-4 as three lines 15.

[0044] The variable underlying the target value 21 can be a speed at which the electric motor 12 is to rotate (the torque generated by the electric motor 12 depends in particular on the counteracting torque of a load acting on the electric motor 12). However, it is also possible to specify a target torque 21 for the electric motor 12. Furthermore, a superposition of the target torque and the target speed is also conceivable.

[0045] The controller 20 generates the setpoint value 21 based on the evaluation of an input signal 22 or various input signals 22 (these are shown in Figures 1-4 as a single arrow 22, which can also represent multiple input signals 22). The setpoint value 21 is generated, for example, by the controller 20 in accordance with standard requirements and transmitted to the frequency converter 14.

[0046] The controller 20 controls the electric motor 12 or the frequency converter 14 based on a target-actual comparison, whereby the controller 20 receives a current actual value 21 transmitted by a detection unit. In this control, the frequency converter 14 acts as an actuator, which is controlled by the controller 20 based on the aforementioned target-actual comparison. The frequency converter 14 can have its own power supply 16. As described above, the control can also take place entirely or partially within the frequency converter 14.

[0047] The arrangement shown in Figures 1-4, with a box 20 representing the controller and a box 14 representing the frequency converter, which are connected to each other via a data connection, is purely schematic and should not be understood as limiting. For example, part of the controller 20 or the entire controller 20 could be integrated into the frequency converter 14.

[0048] The measurement of the quantity underlying the actual value 21 can take place at various points of the electric drive 10 and / or the component 50.

[0049] In the first embodiment of Figure 1, the sensor 30 is located on or in the area of ​​the moving component 50 (e.g., a pivot bearing of a slewing gear or a cable winch connected to the superstructure) or on or in the area of ​​another component connected to the component 50 (e.g., a cable or pinion). The detected value of the variable (or a value derived therefrom) is provided to the controller 20 as the actual value 21.

[0050] In the second embodiment of Figure 2, the sensor 30 is located at the interface 13 between the electric motor 12 and the component 50 (for example in the form of a speed sensor that detects the speed of an output of the electric motor 12 or of a transmission or of a coupling element connected to the component 50, or in the form of a torque or force sensor that detects a torque or force acting on the aforementioned components).

[0051] In the third embodiment of Figure 3, the sensor 30 is located on the electric motor 12.

[0052] In the fourth embodiment of Figure 4, the sensor 30 is located within the frequency converter 14 (which is why the sensor is only indicated by an arrow 30 in Figure 4) and forwards the detected value (or a value derived therefrom) to the controller 20 as an actual value 21.

[0053] The controller 20 compares the supplied actual value 21 with the target value 31 determined from the input signal(s) 22. The controller 20 can comprise a control module, which determines the target value 31 from the input signal(s) 22, and a control module, which receives the target value 31 from the control module and the actual value 21 from the acquisition unit, performs the target-actual comparison, and sends the corresponding control signal in the form of the target value 31 to the frequency converter 14.

[0054] The variable underlying the actual value 21 can be, for example, a torque or a speed and is measured by at least one sensor 30 of the detection unit during operation of the cable excavator. The sensor 30 can be, for example, a speed sensor, a torque flange, or a load cell and, in particular, also meets the aforementioned normative requirements.

[0055] For each drive unit (or each electric drive 10) of the cable excavator, a permissible deviation of the actual value 21 from the target value 31 can be defined. The corresponding deviations or applied criteria and / or limit values ​​can be stored in the controller 20 or in a data memory to which the controller 20 has access.

[0056] Examples of limit values ​​for the permissible deviation between target value 31 and actual value 21 for different components of the cable excavator can be, for example, 10% of the speed at maximum travel speed for a travel drive, 10% of the maximum permissible drive torque and / or 10% of the maximum permissible drive speed for slewing gear and / or 10% of the maximum permissible drive speed for cable winches (e.g. hoist winch, retractable winch) and / or 10% of the maximum winch speed for cable winches (e.g. lifting winch, retractable winch). Values ​​of less or more than 10% of the stated values ​​are of course also conceivable. Depending on the component, variable limit values, e.g. speed- and / or torque-dependent, are also possible. Figure 5 shows an example of a temporal progression of target value 31 and actual value 21 in a diagram, where the x-axis 61 represents the time axis and the y-axis 62 represents the value axis.The time course of the actual value recorded by the recording unit is shown as a solid line 63, and the time course of the target value specified by the controller 20 is shown as a dashed line 64. The dotted line 65 above the target value curve 64 represents the upper limit of the maximum permissible deviation of the actual value from the target value, while the dotted line 66 below the target value curve 64 represents the lower limit of the maximum permissible deviation.

[0057] At the end of the process, the actual value exceeds the upper limit of 65 of the maximum permissible deviation. The control system 20 then automatically takes appropriate action, e.g., intervening in the control system of the cable excavator.

[0058] Depending on the plant and operating status, countermeasures can be defined that are automatically initiated by the control system 20 when the permissible deviation is exceeded in order to ensure a safe state of the duty cycle crane. For a hoist winch, this could, for example, be initiating a Category 0 stop, which stops torque being generated at the associated electric motor 12. A holding brake on the hoist winch is then applied, thus stopping the rotation of the winch and holding the load on the winch.

[0059] Preferably, the cable excavator comprises several units (e.g. at least one hoist winch, at least one retracting winch, at least one travel drive, at least one slewing gear and / or further rotary drives), all of which are driven by electric motors, as described above.

[0060] The cable excavator is preferably a fully electric cable excavator. Alternatively, one or more of the units can be hydraulically operated. The cable excavator can have a purely electric drive or a hybrid drive system with an internal combustion engine and / or a fuel cell. An example of the control sequence for motor 12 or frequency converter 14 is described below.

[0061] The operator of the rope excavator wants to move a workpiece, e.g. lift a load, and generates a target value (e.g. a lifting speed) using the associated control unit (e.g. at least one master switch or joystick). The machine's control system processes the signal and forwards the target value to the frequency converter 14. The actual control now takes place within the frequency converter 14. The target value 21 is evaluated, compared with the actual value 31, and the frequency and / or current for the motor 12 is set accordingly. The machine's control system assumes a monitoring function here: if the control in the frequency converter 14 detects an error, measures are initiated as soon as the actual value 31 deviates too significantly from the target value 21.

[0062] List of reference symbols:

[0063] 10 Electric drive

[0064] 12 electric motor

[0065] 13 Interface

[0066] 14 frequency converters

[0067] 15 Power supply of the electric motor

[0068] 16 Power supply of the frequency converter

[0069] 20 Control

[0070] 21 Target value

[0071] 30 sensors

[0072] 50 Movable component

[0073] 61 x-axis (time axis)

[0074] 62 y-axis (size axis)

[0075] 63 Time course actual value

[0076] 64 Time course target value

[0077] 65 Upper limit

[0078] 66 Lower limit

Claims

Patent claims 1. A cable excavator comprising a mobile undercarriage, a superstructure rotatably mounted on the undercarriage, at least one electric drive (10) for moving a component (50) of the cable excavator, a controller (20) connected to the electric drive (10), and a detection unit connected to the controller for detecting a variable relating to the electric drive (10) or the component (50) to be moved, wherein the electric drive (10) comprises an electric motor (12) and a frequency converter (14) by means of which an adjustable alternating voltage can be provided to the electric motor (12), characterized in that the controller (20) is configured to receive an actual value (31) of the detected variable from the detection unit and to compare it with a target value (21) dependent on an input signal (22).to control the frequency converter (14) depending on this target-actual comparison and to automatically take action in the event of a defined deviation of the actual value (31) from the target value (21).

2. Cable excavator according to claim 1, wherein the control (20) is arranged to Action to be taken if there is a deviation between an actual Torque (31) and a target torque (21) of the electric motor (12) or a variable derived therefrom exceeds or falls below a predetermined limit value or a limit value dependent on an operating state of the electric motor (12).

3. Cable excavator according to claim 1 or 2, wherein the controller (20) is arranged to take a measure when a deviation between an actual speed (31) and a target speed (21) of the electric motor (12) or a variable derived therefrom exceeds or falls below a predetermined limit value or a limit value dependent on an operating state of the electric motor (12).

4. Cable excavator according to one of the preceding claims, wherein the undercarriage comprises an electrically operable chassis, in particular a crawler chassis, and at least one electric drive (10) controllable by the controller (20) is an electric travel drive, wherein the controller (20) is preferably designed to take a measure if a deviation between the actual and target value (21, 31) exceeds a specified factor of a speed related to a maximum travel speed.

5. Cable excavator according to one of the preceding claims, wherein the upper carriage is rotatably connected to the undercarriage via a slewing gear and at least one electric drive (10) controllable by the controller (20) is a rotary drive of the slewing gear, wherein the controller (20) is preferably set up to take a measure if a deviation between the actual and target value (21, 31) exceeds a specified factor of a maximum permissible drive torque and / or a specified factor of a maximum permissible drive speed.

6. Cable excavator according to one of the preceding claims, comprising a cable winch, in particular a hoisting cable winch or retracting winch arranged on the superstructure, wherein at least one electric drive (10) which can be controlled by the control (20) is a drive of the cable winch, wherein the control (20) is preferably set up to take a measure if a Deviation between actual and target value (21, 31) exceeds a specified factor of a maximum winch speed or rotational speed.

7. Cable excavator according to one of the preceding claims, comprising at least two electric drives (10) for moving at least two different components (50) of the cable excavator, wherein different limit values ​​are defined for determining a defined deviation for at least two electric drives (10), wherein the controller (20) is preferably set up to use a different fixed or variable limit value for each electric drive (10).

8. Cable excavator according to one of the preceding claims, wherein all rotary drives of the cable excavator are designed as electric drives (10) which can be controlled by the control system (20), wherein the cable excavator is preferably fully electrically operated.

9. Cable excavator according to one of the preceding claims, wherein the target value (21) supplied to the target-actual comparison is a torque, a speed or a combination of torque and speed.

10. Cable excavator according to one of the preceding claims, wherein the controller (20) comprises a control module and a control module, wherein the control module is set up to determine a target value (21) for the control module on the basis of at least one received input signal (22), and wherein the control module is set up to receive an actual value (31) relating to at least one electric drive (10) of the cable excavator from the detection unit and to compare it with the target value (21) specified by the control module, and preferably to control the frequency converter (14) of the relevant electric drive (10) depending on the target-actual comparison.

11. Cable excavator according to one of the preceding claims, comprising an input unit which is connected to the control (20) and is designed to send an input signal (22) to the control in dependence on a user input. tion (20), wherein the controller (20) is set up to determine a target value (21) for the target-actual comparison of the at least one electric drive (10) as a function of the input signal (22).

12. Cable excavator according to one of the preceding claims, comprising a second detection unit connected to the controller (20), by means of which at least one operating parameter of the cable excavator, a variable relating to the position or movement of a movable component (50) of the cable excavator and / or an environmental parameter can be detected and provided as an input signal (22) to the controller (20), wherein the controller (20) is set up to determine a target value (21) for the target-actual comparison of at least one electric drive (10) depending on the input signal (22).

13. Cable excavator according to one of the preceding claims, wherein the detection unit comprises at least one sensor (30), preferably a speed sensor, a torque sensor, in particular a torque flange, and / or a load cell.

14. Cable excavator according to the preceding claim, wherein at least one sensor (30) is arranged on the electric motor (12) of an electric drive (10) and / or at least one sensor (30) is arranged on a frequency converter (14) of an electric drive (10) and / or at least one sensor (30) is arranged on a component (50) of the cable excavator that is movable by an electric drive (10) and / or at least one sensor (30) is arranged on an interface (13) between an electric motor (12) and a movable component (50) of the cable excavator.

15. Cable excavator according to one of the preceding claims, wherein the measure comprises issuing a warning signal and / or limiting or stopping a current movement of the cable excavator.

Images