Power supply system for electric construction machinery

Abstract

To provide a power feed system for electric construction machinery, in which work efficiency of the electric construction machinery can be improved while preventing damage of a power feed cable. This power feed system comprises: a cable drum for performing paying out and winding up a power feed cable from an external power source; a drum sensor; a rotational angle sensor for detecting a routing direction of the power feed cable with respect to an electric power shovel; a monitor; and a controller. The controller computes a wound-up length of the power feed cable that is wound up on the cable drum, on the basis of a rotational amount of the cable drum detected by the drum sensor, and also displays this wound-up length and the routing direction that is detected by the rotational angle sensor on the monitor at the same time.

Description

Technical Field

[0001] The present invention relates to a power supply system for an electric construction machine that supplies power to the electric construction machine from an external power source via a power supply cable.

Background Art

[0002] An electric excavator, which is one type of electric construction machine, includes, for example, a traveling body, a revolving body rotatably provided above the traveling body, an electric motor mounted on the revolving body, a hydraulic pump mounted on the revolving body and driven by the electric motor, and a hydraulic actuator driven by the pressure oil discharged from the hydraulic pump. In some electric excavators, the power supply cable is configured to be connectable to the revolving body side, and power from an external power source is supplied via the power supply cable. Then, the electric motor is driven by the power supplied via the power supply cable. Alternatively, the battery mounted on the revolving body is charged by the power supplied via the power supply cable, and the electric motor is driven by the power of the battery.

[0003] When the above-described electric excavator performs an operation such as turning with the power supply cable connected, there is a possibility of damaging the power supply cable. Patent Document 1 discloses a cable stand for suppressing damage to the power supply cable. The cable stand of Patent Document 1 is attached to the revolving body of the electric excavator so as to be rotatable about a vertical axis and guides the power supply cable. Then, for example, in response to the rotation of the revolving body, the cable stand rotates in the opposite direction so that an excessive load is not applied to the power supply cable.

[0004] Patent Document 2 discloses a power supply system for supplying power to an electric excavator from an external power source via a power supply cable. This power supply system comprises a cable drum for pulling out and winding the power supply cable from the external power source, a detection unit for detecting the length of the power supply cable pulled out from the cable drum, an alarm unit, and a controller for controlling the alarm unit. The controller controls the alarm unit to issue an alarm when the length of the power supply cable detected by the detection unit is at its maximum. As a result, the operator either operates the electric excavator in a direction closer to the external power source, or operates the electric excavator with the power supply cable disconnected. This makes it possible to reduce damage to the power supply cable. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2018-084099 [Patent Document 2] Korean Published Patent Publication No. 10-2012-0114879 [Overview of the project] [Problems that the invention aims to solve]

[0006] Adopting the cable stand described in Patent Document 1 can reduce damage to the power supply cable. However, although not explicitly stated in Patent Document 1, the rotation range of the cable stand is limited for reasons such as avoiding contact between the cable stand and the cab, etc. If the rotating body of the electric excavator rotates when the rotation of the cable stand has reached its limit, there is a possibility that the power supply cable will get caught. Therefore, the operator must operate the electric excavator while, for example, visually checking the condition of the power supply cable, which leads to a decrease in work efficiency.

[0007] Furthermore, by adopting the power supply system described in Patent Document 2, it is possible to reduce damage to the power supply cable. However, the operator cannot determine the operating range of the electric shovel unless the power supply cable is extended to its maximum length. This leads to a decrease in work efficiency.

[0008] The present invention has been made in view of the above matters, and its purpose is to provide a power supply system for electric construction machinery that can improve the work efficiency of electric construction machinery while preventing damage to the power supply cable. [Means for solving the problem]

[0009] To achieve the above objective, the present invention provides a power supply system for an electric construction machine that supplies power to the electric construction machine from an external power source via a power supply cable, comprising: a cable drum for pulling out and winding the power supply cable from the external power source; a drum sensor for detecting the state quantity of the cable drum that changes due to the pulling out and winding of the power supply cable; a rotation angle sensor for detecting the routing direction of the power supply cable to the electric construction machine; a monitor; and a controller for controlling the display on the monitor, wherein the controller calculates the winding length of the power supply cable wound on the cable drum based on the state quantity of the cable drum detected by the drum sensor, and simultaneously displays the winding length and the routing direction detected by the rotation angle sensor on the monitor. [Effects of the Invention]

[0010] According to the present invention, it is possible to improve the work efficiency of electric construction machinery while preventing damage to the power supply cable. [Brief explanation of the drawing]

[0011] [Figure 1] This diagram shows the configuration of the power supply system in AVA. [Figure 2] This diagram illustrates the structure of a cable drum in one embodiment of the present invention. [Figure 3] This is a right side view showing the overall structure of an electric excavator in one embodiment of the present invention. [Figure 4] This is a rear view showing the overall structure of an electric excavator in one embodiment of the present invention. [Figure 5] This is a perspective view showing the structure of a cable stand for an electric excavator in one embodiment of the present invention. [Figure 6] This is a left side view showing the structure of the cable stand for an electric excavator in one embodiment of the present invention. [Figure 7] This diagram shows the configuration of the boom cylinder in the drive system of an electric excavator in one embodiment of the present invention. [Figure 8] This is a block diagram showing the configuration of the power system of an electric excavator in one embodiment of the present invention, along with related equipment. [Figure 9] This is a flowchart illustrating the display control of the winding length of the power supply cable in one embodiment of the present invention. [Figure 10] This is a flowchart illustrating the display control of the rotation angle of a cable stand in one embodiment of the present invention. [Figure 11A] This figure shows a specific example of the display screen of the monitor for an electric excavator in one embodiment of the present invention. [Figure 11B] This figure shows a specific example of the display screen of the monitor for an electric excavator in one embodiment of the present invention. [Modes for carrying out the invention]

[0012] One embodiment of the present invention will be described with reference to the drawings.

[0013] FIG. 1 is a diagram showing the configuration of the power supply system in the present embodiment. FIG. 2 is a diagram showing the structure of the cable drum in the present embodiment (viewed from the direction of arrow II in FIG. 1). FIG. 3 is a right side view showing the overall structure of the electric excavator in the present embodiment. FIG. 4 is a rear view showing the overall structure of the electric excavator in the present embodiment (viewed from the direction of arrow IV in FIG. 3). FIG. 5 is a perspective view showing the structure of the cable stand of the electric excavator in the present embodiment. FIG. 6 is a left side view showing the structure of the cable stand of the electric excavator in the present embodiment (viewed from the direction of arrow VI in FIG. 5).

[0014] The power supply system of the present embodiment supplies power from an external power source 1 (for example, a commercial power source) to an electric excavator 3 (electric construction machinery) via a power supply cable 2, and includes a cable drum 4 that pulls out and winds up the power supply cable 2 from the external power source 1.

[0015] The cable drum 4 includes a drum body 5 around which the power supply cable 2 is wound, a support base ⑥ that rotatably supports the drum body 5, a spring (not shown) that biases the drum body 5, and a drum sensor 7 that detects the rotation amount of the drum body 5 (hereinafter referred to as the rotation amount of the cable drum 4). When the drum body 5 rotates in one direction against the biasing force of the spring, the power supply cable 2 is pulled out from the drum body 5. Alternatively, when the drum body 5 rotates in the opposite direction by the biasing force of the spring, the power supply cable 2 is wound around the drum body 5. The drum sensor 7 outputs a detection signal to a controller (details will be described later) of the electric excavator 3 via a signal line 8. Therefore, the cable drum 4 also pulls out and winds up the signal line 8.

[0016] The electric excavator 3 includes a traveling body 11, a revolving body 12 provided rotatably above the traveling body 11, and a working device 13 connected to the front side (right side in FIGS. 1 and 3) of the revolving body 12. The traveling body <11> travels by the rotation of a traveling motor (not shown), and the revolving body <12> revolves by the rotation of a revolving motor (not shown).

[0017] The working device 13 includes, for example, a swing post 14 rotatably connected to the front of the slewing body 12 in the left-right direction, a boom 15 rotatably connected to the upper side of the swing post 14 in the up-down direction, an arm 16 rotatably connected to the tip of the boom 15 in the up-down direction, and a bucket 17 rotatably connected to the tip of the arm 16 in the up-down direction. The swing post 14 rotates by the extension and retraction of the swing cylinder 18, the boom 15 rotates by the extension and retraction of the boom cylinder 19, the arm 16 rotates by the extension and retraction of the arm cylinder 20, and the bucket 17 rotates by the extension and retraction of the bucket cylinder 21.

[0018] The rotating body 12 comprises a rotating frame 22 that forms the lower base structure, a cab (driver's compartment) 23 provided on the left side of the rotating frame 22 (the rear side in the plane of Figures 1 and 3), and a counterweight 24 provided on the rear side of the rotating frame 22 (the left side in Figures 1 and 3).

[0019] Furthermore, the rotating body 12 is positioned above the counterweight 24 and includes a cable connector 25 to which the power supply cable 2 can be connected, a connection sensor 26 (see Figure 8 below) that detects when the power supply cable 2 is connected to the cable connector 25, a signal line connector 27 positioned above the counterweight 24 to which the signal line 8 can be connected, and a cable stand 28 mounted above the counterweight 24 so as to be rotatable around a vertical axis, which guides the power supply cable 2 and the signal line 8.

[0020] The cable stand 28 comprises a base 29 fixed to a counterweight 24, a rotating shaft 30 supported by bearings (not shown) of the base 29 so as to be rotatable around a vertical axis, a support frame 31 extending horizontally from the rotating shaft 30, a clamp 32 provided on the tip side of the support frame 31 for gripping the power supply cable 2, a plurality of support members 33 arranged on the rotating shaft 30 and the clamp 32 for supporting the signal line 8, and a rotation angle sensor 34 for detecting the rotation angle of the rotating shaft 30 relative to the base 29 (hereinafter referred to as the rotation angle of the cable stand 28). The rotation angle sensor 34 corresponds to a rotation angle sensor for detecting the routing direction of the power supply cable to the electric construction machine described in the claims, and also corresponds to a rotation angle sensor for detecting the rotation angle of the cable stand around the vertical axis as the routing direction of the power supply cable to the electric construction machine.

[0021] For example, when the slewing body 12 rotates clockwise relative to the traveling body 11 when viewed from above, the rotation axis 30 and support frame 31 of the cable stand 28 rotate counterclockwise relative to the slewing body 12 when viewed from above. Also, for example, when the slewing body 12 rotates counterclockwise relative to the traveling body 11 when viewed from above, the rotation axis 30 and support frame 31 of the cable stand 28 rotate clockwise relative to the slewing body 12 when viewed from above. This prevents excessive load from being placed on the power supply cable 2 and signal line 8. However, the rotation range of the rotation axis 30 is limited by a stopper (not shown) to avoid contact between the support frame 31 of the cable stand 28 and the cab 23, etc.

[0022] In this embodiment, the rotation angle of the cable stand 28 is defined as the reference value (0 degrees) when the support frame 31 is facing the rear of the swivel body 12 (see Figures 1 and 3 to 6). When the rotation angle of the cable stand 28 is defined to increase as the support frame 31 rotates clockwise from the aforementioned state, the rotation angle of the cable stand 28 is limited to, for example, 90 degrees (the limit on one side). Also, when the rotation angle of the cable stand 28 is defined to increase as the support frame 31 rotates counterclockwise from the aforementioned state, the rotation angle of the cable stand 28 is limited to, for example, 90 degrees (the limit on the other side).

[0023] The cab 23 is equipped with a driver's seat (not shown) where an operator sits. In front of the driver's seat are a travel control lever and pedal (not shown) that can be operated by the operator. The travel control lever and pedal instruct the movement of the vehicle 11 by being operated in the forward and backward directions. To the right of the travel control lever is a swing control pedal (not shown) that can be operated by the driver. The swing control pedal instructs the movement of the swing post 14 by being operated in the left and right directions.

[0024] To the left of the driver's seat is a work control lever (not shown) that can be operated by the operator. This work control lever controls the movement of the slewing body 12 when operated left or right, and controls the movement of the arm 16 when operated forward or backward. To the right of the driver's seat is a work control lever 35 (see Figure 7 below) that can be operated by the operator. This work control lever 35 controls the movement of the bucket 17 when operated left or right, and controls the movement of the boom 15 when operated forward or backward.

[0025] A lock lever 36 (see Figure 7 below) that can be operated by the operator is provided on the left side of the driver's seat. The lock lever 36 can be selectively operated to a locked position and an unlocked position. In this embodiment, the lock lever is a gate lock lever provided at the entrance to the cab 23. When operated to the locked position (up position), it allows the operator to get on and off, and when operated to the unlocked position (down position), it prevents the operator from getting on and off. A monitor 37 (see Figure 8 below) that can be viewed or operated by the operator is provided on the right side and in front of the driver's seat.

[0026] The electric excavator 3 is equipped with a drive system that drives multiple hydraulic actuators (specifically, the travel motor, swing motor, swing cylinder 18, boom cylinder 19, arm cylinder 20, and bucket cylinder 21 mentioned above). Figure 7 is a diagram showing the configuration of the boom cylinder 19 in the drive system of the electric excavator 3 in this embodiment.

[0027] The drive system of this embodiment includes an electric motor 38, a hydraulic pump 39 and a pilot pump 40 driven by the electric motor 38, a control valve 41 that controls the flow of pressurized oil (specifically, direction and flow rate) from the hydraulic pump 39 to the boom cylinder 19, and an operating device 42 that switches the control valve 41. The operating device 42 is mounted on the cab 23 of the slewing body 12, while the electric motor 38, hydraulic pump 39, pilot pump 40, and control valve 41 are mounted on other parts of the slewing body 12.

[0028] The operating device 42 includes the aforementioned work operating lever 35, a pilot valve 43A that reduces the discharge pressure of the pilot pump 40 to generate pilot pressure according to the amount of forward operation of the work operating lever 35, and a pilot valve 43B that reduces the discharge pressure of the pilot pump 40 to generate pilot pressure according to the amount of rearward operation of the work operating lever 35.

[0029] When the operator operates the work lever 35 forward, the pilot pressure generated by the pilot valve 43A according to the amount of operation is output to the pressure receiving section 44A of the control valve 41, thereby switching the control valve 41 to the switching position shown on the right in the figure. This causes the boom cylinder 19 to retract. When the operator operates the work lever 35 backward, the pilot pressure generated by the pilot valve 43B according to the amount of operation is output to the pressure receiving section 44B of the control valve 41, thereby switching the control valve 41 to the switching position shown on the left in the figure. This causes the boom cylinder 19 to extend.

[0030] Furthermore, the configurations for the other actuators (specifically, the travel motor, slewing motor, swing cylinder 18, arm cylinder 20, and bucket cylinder 21) are the same as those for the boom cylinder 19. That is, the corresponding control valve is switched by pilot pressure from the corresponding operating device, and the other actuators are operated by pressurized oil supplied from a hydraulic pump via this control valve.

[0031] The drive unit of this embodiment further includes a lock valve 45 provided between all the operating devices and the pilot pump 40, which serves as a locking device that can switch between an inactive state (locked state) and an active state (unlocked state) of the operation of the electric shovel 3.

[0032] The lock valve 45 is switched according to the operation of the lock lever 36 described above. More specifically, the lock lever 36 is equipped with a lock switch 46. When the lock lever 36 is operated to the locked position (up position), the lock switch 46 opens. As a result, the solenoid part of the lock valve 45 is not energized, so the lock valve 45 is in the shut-off position shown on the right in the figure, and the discharge pressure of the pilot pump 40 is not introduced to any of the operating devices (locked state). Therefore, the driving of all hydraulic actuators is prohibited. On the other hand, when the lock lever 36 is operated to the unlocked position (down position), the lock switch 46 closes. As a result, the solenoid part of the lock valve 45 is energized, and the lock valve 45 is switched to the communicative position shown on the left in the figure, and the discharge pressure of the pilot pump 40 is introduced to all of the operating devices (unlocked state). Therefore, the driving of all actuators is permitted (unlocked state). The lock switch 46 corresponds to an operation detection device that detects the active and inactive states of the operation of the electric construction machine described in the claims.

[0033] The electric motor 38 is driven by power supplied from an external power source 1 via a power supply cable 2. Alternatively, it is driven by power from a battery 47 (see Figure 8, described later) that has been charged by power supplied from an external power source 1 via a power supply cable 2. The electrical system of the electric excavator 3 configured in this way will be explained using Figure 8. Figure 8 is a block diagram showing the configuration of the electrical system of the electric excavator in this embodiment, along with related equipment.

[0034] The electrical system of this embodiment includes a rectifier 48 that converts AC power supplied from an external power source 1 via a power supply cable 2 into DC power, an inverter 49 that controls the rotational speed of the electric motor 38, a switch 50 that switches the connection between the rectifier 48, the inverter 49, and the battery 47, and a controller 51 that controls the switch 50, the inverter 49, and the monitor 37, etc. The battery 47, rectifier 48, inverter 49, switch 50, and controller 51 are mounted on the slewing body 12.

[0035] Although not shown, the controller 51 includes a processor that executes processing according to a program, and memory for storing programs and data. When the connection sensor 26 detects that the power supply cable 2 is connected to the cable connector 25, the controller 51 controls the changeover switch 50 to connect the rectifier 48 to the inverter 49 or battery 47. In this case, the electric motor 38 is driven by power supplied from the external power supply 1 via the power supply cable 2.

[0036] Alternatively, when the controller 51 detects with the connection sensor 26 that the power supply cable 2 is connected to the cable connector 25, it controls the changeover switch 50 to connect the rectifier 48 and the battery 47. This allows the battery 47 to be charged by the power supplied from the external power source 1 via the power supply cable 2. When the controller 51 detects with the connection sensor 26 that the power supply cable 2 is not connected to the cable connector 25, it controls the changeover switch 50 to connect the inverter 49 and the battery 47. In this case, the electric motor 38 is driven by the power from the battery 47.

[0037] Herein, a feature of this embodiment is that the controller 51 calculates the winding length of the power supply cable 2 wound on the cable drum 4 based on the amount of rotation of the cable drum 4 detected by the drum sensor 7. The controller then controls the display of the calculated winding length and the rotation angle of the cable stand 28 detected by the rotation angle sensor 34 (in other words, the routing direction of the power supply cable 2 relative to the electric shovel 3) simultaneously on the monitor 37. The display control of the winding length of the power supply cable 2 and the display control of the rotation angle of the cable stand 28 will be explained separately below.

[0038] The display control of the winding length of the power supply cable 2 will be explained using Figure 9. Figure 9 is a flowchart showing the contents of the display control of the winding length of the power supply cable in this embodiment.

[0039] In step S1, the controller 51 determines, based on the detection result of the connection sensor 26, whether the power supply cable 2 is connected to the cable connector 25. If the power supply cable 2 is connected to the cable connector 25, the process proceeds to step S2. In step S2, the controller 51 calculates the winding length L of the power supply cable 2 based on the amount of rotation of the cable drum 4 detected by the drum sensor 7. The process then proceeds to step S3, where the winding length L of the power supply cable 2 is displayed on the monitor 37. For example, as shown in Figure 11A, the display screen 60A of the monitor 37 displays the numerical value of the winding length La of the power supply cable 2, and the power supply cable icon 63 between the external power icon 61 and the shovel icon 62 visually displays the length of the power supply cable 2 pulled out from the cable drum 4. Furthermore, as shown in Figure 11B, for example, the display screen 60B of the monitor 37 displays the numerical value of the winding length Lb of the power supply cable 2, and the power supply cable icon 63 between the external power icon 61 and the shovel icon 62 visualizes the length of the power supply cable 2 pulled out from the cable drum 4.

[0040] The process proceeds to step S4, where the controller 51 determines whether the lock valve 45 is locked based on whether the lock switch 46 is open. If the lock valve 45 is not locked, the process moves to step S5. In step S5, the controller determines whether the winding length L of the power supply cable 2 is less than or equal to a predetermined value Lth (where Lth > 0). If the winding length L of the power supply cable 2 is less than or equal to the predetermined value Lth, the process moves to step S6. In step S6, an alarm is issued by displaying a message on the monitor 37, for example, "The winding length of the power supply cable is too short." Note that if the lock valve 45 is locked (i.e., the operation of the electric shovel 3 is disabled), the process does not proceed to steps S5 and S6, and no alarm is issued.

[0041] As a result, the operator can easily check the winding length of the power supply cable 2 and understand the operating range of the electric excavator 3 at any time. Therefore, the work efficiency of the electric excavator 3 can be increased. In addition, if an alarm regarding the winding length of the power supply cable 2 is issued, the operator can operate the electric excavator 3 in a direction closer to the external power source 1, or operate the electric excavator 3 with the power supply cable 2 disconnected. Therefore, damage to the power supply cable 2 can be minimized.

[0042] The display control of the rotation angle of the cable stand 28 will be explained using Figure 10. Figure 10 is a flowchart showing the contents of the display control of the rotation angle of the cable stand in this embodiment.

[0043] In step S1, the controller 51 determines, based on the detection result of the connection sensor 26, whether the power supply cable 2 is connected to the cable connector 25. If the power supply cable 2 is connected to the cable connector 25, the process proceeds to step S7. In step S7, the controller 51 displays the rotation angle θ of the cable stand 28 detected by the rotation angle sensor 34 on the monitor 37. For example, as shown in Figure 11A, the rotation angle θa of the cable stand 28 is displayed as an image on the display screen 60A of the monitor 37 based on the orientation of the cable stand icon 65 relative to the shovel icon 64. Also, for example, as shown in Figure 11B, the rotation angle θb of the cable stand 28 is displayed as an image on the display screen 60B of the monitor 37 based on the orientation of the cable stand icon 65 relative to the shovel icon 64.

[0044] The process proceeds to step S4, where the controller 51 determines whether the lock valve 45 is locked based on whether the lock switch 46 is open. If the lock valve 45 is not locked, the process moves to step S8. In step S8, the controller determines whether the rotation angle θ of the cable stand 28 has reached a set value θth on one side of the rotation direction (specifically, a value pre-set so that it is within the range of the limit value on one side that limits the rotation range of the cable stand 28, for example, 80 degrees) or a set value θth on the other side of the rotation direction (specifically, a value pre-set so that it is within the range of the limit value on the other side that limits the rotation range of the cable stand 28, for example, 80 degrees). If the rotation angle θ of the cable stand 28 has reached a set value θth on one side of the rotation direction or a set value θth on the other side, the process moves to step S9. In step S9, an alarm is issued by displaying a message on the monitor 37, for example, "The rotation angle of the cable stand is large." Furthermore, if the lock valve 45 is locked (i.e., the operation of the electric shovel 3 is disabled), the system will not proceed to steps S8 and S9, and no alarm will be issued.

[0045] As a result, the operator can easily check the rotation angle of the cable stand 28 and understand the operating range of the electric excavator 3 at any time. Therefore, the work efficiency of the electric excavator 3 can be increased. In addition, if an alarm regarding the rotation angle of the cable stand 28 is issued, the operator can operate the electric excavator 3 in a direction closer to the external power source 1, or operate the electric excavator 3 with the power supply cable 2 disconnected. Therefore, damage to the power supply cable 2 can be minimized.

[0046] In the above embodiment, the drum sensor 7 was described as detecting the amount of rotation of the drum body 5, but it is not limited to this, and it is sufficient to detect the state of the cable drum 4 that changes due to the pulling out and winding of the power supply cable 2. The drum sensor 7 may, for example, detect the weight of the drum body 5.

[0047] Furthermore, in the above embodiment, the controller 51 was described as displaying messages on the monitor 37 (notification device) as an alarm for the winding length of the power supply cable 2 and the rotation angle of the cable stand 28, but it is not limited to this, and notification may be provided by other notification devices. That is, an alarm may be provided by a buzzer or the like.

[0048] Furthermore, although the above embodiment described an example in which the drum sensor 7 outputs a detection signal to the controller 51 of the electric excavator 3 via the signal line 8, the invention is not limited to this. The drum sensor 7 may also output a detection signal to the controller 51 of the electric excavator 3 via wireless communication. In this case, the cable drum 4 does not extend or retract the signal line 8.

[0049] Furthermore, although the above embodiment described the electric construction machine as an electric excavator, it is not limited to this. In other words, any electric construction machine equipped with a traveling body, a slewing body rotatably mounted above the traveling body, and a working device connected to the slewing body is acceptable, such as an electric crane. [Explanation of Symbols]

[0050] 1 External power supply 2 Power supply cable 3. Electric excavator (electric construction machine) 4 Cable drums 7 Drum Sensor 11. Running body 12. Rotating body 28 Cable Stands 34 Rotation Angle Sensor 37 monitors 46. ​​Lock switch (operation detection device) 51 Controllers

Claims

1. In a power supply system for electric construction machinery that supplies power to the electric construction machinery from an external power source via a power supply cable, A cable drum for drawing out and winding the power supply cable from the external power source, A drum sensor that detects the state of the cable drum which changes due to the pulling out and winding of the power supply cable, A rotation angle sensor for detecting the routing direction of the power supply cable to the electric construction machine, Monitor and, The system includes a controller that controls the display on the monitor, The controller calculates the winding length of the power supply cable wound around the cable drum based on the state of the cable drum detected by the drum sensor, and simultaneously displays the winding length and the routing direction detected by the rotation angle sensor on the monitor. A power supply system for electric construction machinery characterized by the following features.

2. In the power supply system for an electric construction machine according to claim 1, It is mounted on the electric construction machine in a manner that allows it to rotate around a vertical axis, and includes a cable stand that guides the power supply cable, The rotation angle sensor detects the rotation angle around the vertical axis of the cable stand as the routing direction of the power supply cable to the electric construction machine. A power supply system for electric construction machinery characterized by the following features.

3. In the power supply system for an electric construction machine according to claim 2, The cable stand is attached to a rotating body that is rotatably mounted on the upper side of the traveling body of the electric construction machine. A power supply system for electric construction machinery characterized by the following features.

4. In the power supply system for an electric construction machine according to claim 1, If the winding length falls below a predetermined value, or if the routing direction reaches a set value, the notification device will issue a notification. A power supply system for electric construction machinery characterized by the following features.

5. In the power supply system for an electric construction machine according to claim 1, The aforementioned controller, The notification device will issue a notification when the winding length falls below a predetermined value, or when the routing direction reaches a set value on one side of the rotation direction or the other side. A power supply system for electric construction machinery characterized by the following features.

6. In the power supply system for an electric construction machine according to claim 2, The aforementioned controller, When the winding length falls below a predetermined value, or when the rotation angle of the cable stand reaches a set value on one side of the rotation direction or a set value on the other side, the notification device will issue a notification. The setting value on one side is pre-set to be within the range of the limiting value on the other side that restricts the rotation range of the cable stand, and the setting value on the other side is pre-set to be within the range of the limiting value on the other side that restricts the rotation range of the cable stand. A power supply system for electric construction machinery characterized by the following features.

7. In the power supply system for an electric construction machine according to claim 4, The electric construction machine is equipped with an operation detection device that detects the active and inactive states of operation, The aforementioned controller, If the motion detection device detects that the electric construction machine is not operating, the notification device will stop notifying the operator even if the winding length is less than or equal to the predetermined value, or if the routing direction reaches the set value. A power supply system for electric construction machinery characterized by the following features.

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