High-speed mobile cable service life detection method

Abstract

A method for detecting the service life of a high-speed mobile cable, the test steps include: 1) Test preparation: Wind the cable under test counterclockwise on a high reel, pull the head of the cable under test off the high reel, pass it through multiple routing guide wheels in sequence, and then pull it upward to fix the head of the cable under test on the low reel; 2) Test process: Simultaneously start the drive motors of the high and low reels to rotate the low and high reels clockwise; the cable under test is unwound from the high reel and gradually wound onto the low reel; after the cable under test is wound on the low reel, adjust the high and low reels to reverse, and unwound from the low reel to the high reel; repeat this cycle; 3) Cable verification: Perform a power frequency withstand voltage test on the cable; 4) Data calculation: Minimum service life = continuous operation time of the cable in the test × (24 hours / actual continuous operation time of the cable per day). Using this method, the service life of a high-speed mobile cable can be characterized close to actual working conditions.

Description

Technical Field

[0001] The present invention relates to the field of cable test simulation technology, and specifically relates to a method for detecting the service life of a high-speed mobile cable. Background Art

[0002] Mobile cables are widely used in industrial production, for example, in RTG (Ryd-Tyred Gantry Crane) applications in the Middle East. As a key piece of equipment in specialized container terminals, RTGs offer flexible transfer operations and minimal engineering investment, making them widely used in ports and terminals. With environmental protection requirements, the accompanying mobile cables are increasingly being used in RTG equipment.

[0003] With the continuous increase in operational efficiency, the demand for cable movement speeds is getting faster and faster. However, cables made by conventional cable sheath extrusion processes are very prone to sheath delamination and voiding as the movement speed increases. In order to facilitate the adjustment of design / manufacturing processes and make cable products meet the requirements of such movement conditions, it is necessary to conduct simulated operation tests to verify the cable's movement performance and ensure that it meets the requirements.

[0004] Therefore, in the development and production of cables, a test system method suitable for the key characteristics of high-speed mobile cables (mainly referring to the cable's moving speed) is needed to conduct cable tests and ensure that the cable performance meets the requirements of mobile operating conditions. However, in the existing technology, there is currently no unified testing standard and method for reference. Summary of the Invention

[0005] The main purpose of the present invention is to provide a test method for key characteristics of high-speed mobile cables, which is used to simulate or test the actual operating speed and related service life of high-speed mobile cables.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A high-speed mobile cable service life test method employs a dedicated test simulation platform comprising: a high and a low reel with a height difference, with multiple routing guide wheels positioned between the two reels, the routing guide wheels being lower than the two reels; the rotation of the two reels is driven by a drive motor; the path of the cable under test is as follows: it descends from the high reel, passes through each routing guide wheel in sequence, and then rises and winds onto the low reel;

[0008] The test steps include:

[0009] Step 1) Experimental preparation:

[0010] Step 1.1) Wind the cable under test counterclockwise around the high reel for 7 to 10 turns.

[0011] Step 1.2) Pull the head of the cable under test down from the high reel, pass it through several guide wheels, and then pull it upward to secure it on the low reel.

[0012] Step 2) Test process:

[0013] Step 2.1) Simultaneously start the drive motors of the high and low reels, causing the low and high reels to rotate clockwise; the cable under test is unwound from the high reel and gradually wound onto the low reel;

[0014] Step 2.2) After the cable under test has been wound 8-9 times on the lower reel, adjust the upper and lower reels to reverse direction and gradually wind the cable under test from the lower reel to the upper reel.

[0015] Steps 2.1) to 2.2) are repeated until the cable under test runs for the required time or the cable under test breaks, and then the test stops.

[0016] Step 3) Cable Verification

[0017] Further inspection of the unbroken cables after step 2):

[0018] First, the entire length of the cable is inspected and the broken wire rate of each core conductor shall not exceed 10%;

[0019] Then, the cable is subjected to a power frequency withstand voltage test, and the insulation cores are not broken down. The test voltage and time are shown in Table 1;

[0020] Table 1 Test voltage and time

[0021] Rated voltage 150 / 250V 0.6 / 1kV 3.6 / 6kV 6 / 10kV 8.7 / 15kV 12 / 20kV Test voltage (kV) 1.5 3.5 12.5 21.0 30.5 42.0 Duration (min) 5 5 5 5 5 5

[0022] Step 4) Data calculation (i.e. service life calculation)

[0023] The cable runs continuously for 1440 hours at the corresponding moving speed. However, under actual operating conditions, the cable runs continuously for no more than 1 hour per day. Therefore, the minimum service life of the cable in actual operation (the moving speed does not exceed the moving speed in the test) is obtained.

[0024] Calculation formula: Minimum service life = continuous operation time of the cable in the test × (24 hours / actual continuous operation time of the cable per day)

[0025] In step 2), the cable running speed (ie, the linear speed of the cable movement) is 30 to 300 m / min, and the test duration of step 2) is 1440 hours.

[0026] If the cable runs at a speed of 300 m / min and performs step 3) after running for 1440 hours, the withstand voltage test requirements are met; if the cable runs for 1 hour per day under actual working conditions, the minimum service life of the cable = 1440 × (24 / 1) = 1440 days = 3.95 years.

[0027] The principle of the present invention is described as follows:

[0028] Test conditions: Cable running speed 30-300m / min (the actual running speed is tested according to the actual working conditions of the cable)

[0029] Data calculation (i.e. service life calculation): The cable runs continuously for 1440 hours at the corresponding moving speed. According to the actual usage of the user, the cable runs continuously for no more than 1 hour per day. Therefore, the minimum service life of the cable in the actual operation process (the moving speed does not exceed the moving speed in the test) can be calculated.

[0030] Calculation formula: Minimum service life = continuous operation time of the cable in the test × (24 hours / actual continuous operation time of the cable per day)

[0031] If the cable runs at a speed of 300 m / min and is tested after 1440 hours of operation, it will meet the withstand voltage test requirements. If the cable runs for one hour per day under actual operating conditions, the minimum service life of the cable = 1440 × (24 / 1) = 1440 days = 3.95 years.

[0032] The actual operation of the cable is not continuous. Considering that continuous operation during the test will stretch the cable sheath and conductor and cause material fatigue, if the test is carried out for a period of time every day and the cable is not used for the rest of the time, the material fatigue of the sheath and conductor will be alleviated to a certain extent after stretching, which will extend the service life of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a structural diagram of the platform in this example;

[0034] Figure 2a and Figure 2b They are the main view and left view of the high and low reels respectively.

[0035] In the figure: high support frame 1, high reel 2, first routing guide wheel 3, second routing guide wheel 4, third routing guide wheel 5, fourth routing guide wheel 6, fifth routing guide wheel 7, sixth routing guide wheel 8, seventh routing guide wheel 9, low reel 10, and low support frame 11. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0037] A high-speed mobile cable service life test method, using a test simulation dedicated platform (reference Figure 1 、 Figure 2a and Figure 2b ), which includes: a high and a low reel with a height difference, with multiple routing guide wheels between the two reels, and the height of the routing guide wheels is lower than the two reels; the rotation of the two reels is driven by a drive motor; the path of the cable under test is: descending from the high reel, passing through each routing guide wheel in sequence, and then rising and winding on the low reel;

[0038] The test steps include:

[0039] Step 1) Experimental preparation:

[0040] Step 1.1) Wind the cable under test counterclockwise around the high reel for 7 to 10 turns.

[0041] Step 1.2) Pull the head of the cable under test down from the high reel, pass it through several guide wheels, and then pull it upward to secure it on the low reel.

[0042] Step 2) Test process:

[0043] Step 2.1) Simultaneously start the drive motors of the high and low reels, causing the low and high reels to rotate clockwise; the cable under test is unwound from the high reel and gradually wound onto the low reel;

[0044] Step 2.2) After the cable under test has been wound 8-9 times on the lower reel, adjust the upper and lower reels to reverse direction and gradually wind the cable under test from the lower reel to the upper reel.

[0045] Steps 2.1) to 2.2) are repeated until the cable under test runs for the required time or the cable under test breaks, and then the test stops.

[0046] Step 3) Cable Verification

[0047] Further inspection of the unbroken cables after step 2):

[0048] First, the entire length of the cable is inspected and the broken wire rate of each core conductor shall not exceed 10%;

[0049] Then, the cable is subjected to a power frequency withstand voltage test, and the insulation cores are not broken down. The test voltage and time are shown in Table 1;

[0050] Table 1 Test voltage and time

[0051] Rated voltage 150 / 250V 0.6 / 1kV 3.6 / 6 kV 6 / 10 kV 8.7 / 15 kV 12 / 20 kV Test voltage (kV) 1.5 3.5 12.5 21.0 30.5 42.0 Duration (min) 5 5 5 5 5 5

[0052] Step 4) Data calculation (i.e. service life calculation)

[0053] The cable runs continuously for 1440 hours at the corresponding moving speed. However, under actual operating conditions, the cable runs continuously for no more than 1 hour per day. Therefore, the minimum service life of the cable in actual operation (the moving speed does not exceed the moving speed in the test) is obtained.

[0054] Calculation formula: Minimum service life = continuous operation time of the cable in the test × (24 hours / actual continuous operation time of the cable per day)

[0055] In step 2), the cable running speed (ie, the linear speed of the cable movement) is 30 to 300 m / min, and the test duration of step 2) is 1440 hours.

[0056] If the cable runs at a speed of 300 m / min and performs step 3) after running for 1440 hours, the withstand voltage test requirements are met; if the cable runs for 1 hour per day under actual working conditions, the minimum service life of the cable = 1440 × (24 / 1) = 1440 days = 3.95 years.

[0057] refer to Figure 1 、 Figure 2a and Figure 2b The simulation test platform used in this testing method includes a high reel 2, a low reel 10, and multiple cable guide wheels, whose rotation axes are parallel. The high reel 2 and the low reel 10 are connected to a horizontal plane via a high support frame 1 and a low support frame 11, respectively. The cable guide wheels are arranged in sequence between the high reel 2 and the low reel 10. The rotation axis of the high reel 2 is higher than that of the low reel 10, and the rotation axis of each cable guide wheel is lower than that of the low reel 10. The high reel 2 and the low reel 10 are respectively connected to a drive motor. The path of the cable under test is as follows: it descends from the high reel 2, passes through each cable guide wheel in sequence, and then rises and is wound around the low reel 10.

[0058] This simulation platform is closer to the actual operating conditions of high-speed mobile cables.

[0059] Each cable guide wheel is divided into: a middle cable guide wheel for supporting the cable, and two end cable guide wheels for guiding the cable to naturally transition from the high and low reels to the middle cable guide wheel;

[0060] The heights of the intermediate wiring guide wheels are the same, and the spacing between adjacent intermediate wiring guide wheels is equal; the intermediate wiring guide wheel is between the wiring guide wheels at both ends, and the heights of the wiring guide wheels at both ends are higher than the height of the intermediate wiring guide wheel.

[0061] The inner diameter of the routing guide wheels at both ends (I-shaped wheels can be used) is 3 to 5 mm larger than the outer diameter of the cable being tested.

[0062] The relationship between the inner diameter B of the high and low reels and the outer diameter r of the cable under test is:

[0063] 1) When r is not greater than 25 mm (the bending test is performed with a bending radius not greater than 4 times the cable outer diameter r), B ≤ 8r;

[0064] 2) When r is greater than 25 mm (the bending test is carried out with a bending radius not greater than 6 times the cable outer diameter r), B ≤ 12r.

[0065] The above relationship between the inner diameter B of the high and low reels and the outer diameter r of the tested cable (which meets the cable bending test requirements) can avoid excessive bending of the cable, making the cable fit snugly when wound on the reel and meeting the use requirements when simulating mobile working conditions.

[0066] The inner width D of the high reel 2 and low reel 10 is equal to the cable outer diameter + (3-5) mm. This design is designed to prevent friction between the cable and the reel surface, causing sheath wear, if the inner diameter is too small. Excessive friction during cable operation can cause cable breakage or damage to the reel. Excessive inner width can cause cables to stack on adjacent layers, squeezing the cables during operation, reducing cable life, and damaging the reel.

[0067] In actual use, the high reel 2 and the low reel 10 have the same structural dimensions, and during the forward / reverse rotation of the two reels, the simulated working conditions of the cable are most similar.

[0068] As an optimization, the rotating shaft of the high reel 2 and the rotating shaft of the low reel 10 are connected to the same drive motor through transmission mechanisms respectively; a clutch mechanism is also connected between the rotating shaft of the high reel 2 and the transmission mechanism; a clutch mechanism is also connected between the rotating shaft of the low reel 10 and the transmission mechanism.

[0069] During the test preparation stage, when the tested cable is pre-wound onto the reel, the clutch mechanism and the transmission mechanism are engaged / disengaged to facilitate connection and pre-wounding.

[0070] The transmission mechanism consists of a single-input, dual-output reducer and a sprocket drive mechanism. The reducer's input shaft is connected to the drive motor, while its two output shafts are connected to the rotating shafts of the high and low reels via sprocket drives. Both reels share the same drive motor, ensuring good synchronization. Gear and sprocket drives are traditionally well-established and practical for high-precision transmission. In this platform, due to the large spacing between the two reels, a sprocket drive is more practical.

[0071] For example, the transmission mechanism consists of a single-input, dual-output reducer connected to separate sprockets. The reducer's two output shafts are connected to the rotating shafts of the two sprockets via electronic clutches. The two sprockets are then connected to the high and low reels, respectively, via a chain drive mechanism. First, disengage the clutches of the high and low reels. Once the cable's head end is connected and pre-wound around the high reel, operate the high reel independently. Once wound, engage the clutch of the high reel. Connect the tail end of the cable and wind it tightly around the low reel (at this point, the cable tension can be checked using a tension meter to ensure it reaches the specified value). Then, engage the clutch of the low reel. This completes the cable pre-wound process.

[0072] Using this platform, the high-speed mobile cable can move back and forth between two reels with a height difference, which is close to the actual use conditions of the high-speed mobile cable and is conducive to characterizing the service life of the high-speed mobile cable in a close-to-actual working condition.

[0073] The structural data of this platform:

[0074] The distance between the center of the high reel 2 and the ground (rotation axis) is F = 5000mm, the diameter of the reel shaft hole is C = 60mm, the inner width of the reel is D = 100mm, and the inner diameter of the reel (inner ring diameter) B is related to the outer diameter of the cable, and the outer diameter of the reel is A = 3000mm;

[0075] The center of the low reel 10 (rotation axis) is G = 2000mm from the ground, the reel shaft hole diameter C = 60mm, the reel inner width D = 100mm, the reel inner diameter B is related to the cable outer diameter, and the reel outer diameter A = 3000mm.

[0076] The distance between the centers of the high reel 2 and the low reel 10 is E=15000 mm.

[0077] A is the outer diameter of the disc, which is 3000mm;

[0078] B is the inner diameter of the reel. The method for selecting the inner diameter of the reel is: when the outer diameter of the cable is not greater than 25mm, B≤8r; when the outer diameter of the cable is greater than 25mm, B≤12r.

[0079] C is the diameter of the disc shaft hole, which is 60mm;

[0080] D is the inner width of the reel, which is 100mm.

[0081] In this example, the distance between the first routing guide wheel 3 and the seventh routing guide wheel 9 is 9 meters. The second routing guide wheel 4 to the sixth routing guide wheel 8 are evenly distributed between the first routing guide wheel 3 and the seventh routing guide wheel 9.

[0082] Specifically, the number of routing guide wheels can be increased or decreased according to the actual situation. The main purpose is to prevent the cable from bending between the two routing guide wheels to prevent the test results from being affected.

Claims

1. A high-speed mobile cable service life test method, characterized by A dedicated test simulation platform is used, consisting of a high and low reel with a height difference. Multiple guide rollers are located between the two reels, and the height of the guide rollers is lower than that of the two reels. The rotation of the two reels is driven by a drive motor. The path of the cable under test is as follows: it descends from the high reel, passes through each guide roller in sequence, and then rises to be wound on the low reel. The test steps include: Step 1) Experimental preparation: Step 1.1) Wind the cable under test counterclockwise around the high reel for 7 to 10 turns; Step 1.2) Pull the cable head under test from the high reel, pass it through several guide wheels, and then pull it upward to secure it on the low reel. Step 2) Test process: Step 2.1) Simultaneously start the drive motors of the high and low reels, causing the low and high reels to rotate clockwise. The cable under test is unwound from the high reel and gradually wound onto the low reel. Step 2.2) After the cable under test has been wound 8-9 times on the lower reel, adjust the upper and lower reels to reverse direction and gradually wind the cable under test from the lower reel to the upper reel. Repeat steps 2.1) to 2.2) until the cable under test runs for the required time or the cable under test breaks, then stop. Step 3) Verification of the tested cable: Further test the unbroken cables after step 2): First, the entire length of the tested cable is taken as the inspection object, and the broken wire rate of each core conductor shall not exceed 10%; Then, the tested cable is subjected to a power frequency withstand voltage test. The insulation cores are not broken down. The test voltage and time are: If the rated voltage is 150 / 250V, the test voltage is 1.5 kV and the duration is 5 minutes; If the rated voltage is 0.6 / 1kV, the test voltage is 3.5kV and the duration is 5min; If the rated voltage is 3.6 / 6kV, the test voltage is 12.5kV and the duration is 5min; If the rated voltage is 6 / 10kV, the test voltage is 21.0kV and the duration is 5min; If the rated voltage is 8.7 / 15 kV, the test voltage is 30.5 kV and the duration is 5 minutes; If the rated voltage is 12 / 20 V, the test voltage is 42.0 kV and the duration is 5 minutes; Step 4) Data calculation: The tested cable was operated continuously for 1440 hours at the corresponding moving speed. However, under actual operating conditions, the tested cable does not operate continuously for more than 1 hour per day. Therefore, the minimum service life of the tested cable in actual operation was obtained. Calculation formula: Minimum service life = continuous operation time of the cable in the test × (24 hours / actual continuous operation time of the cable per day).

2. The high-speed mobile cable service life test method according to claim 1 is characterized in that In step 2), the operating speed of the tested cable is 30 to 300 m / min, and the continuous operating time of the test in step 2) is 1440 hours.

3. The high-speed mobile cable service life test method according to claim 1 is characterized in that If the tested cable runs at a speed of 300 m / min, proceed to step 3 after running for 1440 hours) to meet the withstand voltage test requirements; The actual continuous operating time of the tested cable is 1 hour per day, so the minimum service life of the tested cable = 1440 × (24 / 1) = 1440 days = 3.95 years.

4. The high-speed mobile cable service life test method according to claim 1, characterized in that In the test simulation dedicated platform, the high reel (2), the low reel (10) and the plurality of wire guide wheels have their rotation axes parallel; The high reel (2) and the low reel (10) are connected to a horizontal plane via a high support frame (1) and a low support frame (11), respectively; and each wire guide wheel is sequentially arranged between the high reel (2) and the low reel (10); The rotation axis of the high reel (2) is higher than the rotation axis of the low reel (10), and the rotation axis of each routing guide wheel is lower than the rotation axis of the low reel (10); the high reel (2) and the low reel (10) are respectively connected to the drive motor; The path of the cable under test is: it descends from the high reel (2) and passes through each routing guide wheel in sequence, and then rises and is wound on the low reel (10).

5. The high-speed mobile cable service life test method according to claim 4 is characterized in that In the test simulation platform, the routing guide wheels are divided into: The middle guide wheel for supporting the cable under test, and the two end guide wheels for guiding the cable under test to transition naturally from the high and low reels to the middle guide wheels; The heights of the intermediate guide wheels are the same, and the spacing between adjacent guide wheels is equal; The middle wiring guide wheel is between the wiring guide wheels at both ends, and the heights of the wiring guide wheels at both ends are higher than the height of the middle wiring guide wheel.

6. The high-speed mobile cable service life test method according to claim 4, characterized in that In the test simulation platform, the inner diameter of the guide wheels at both ends is 3 to 5 mm larger than the outer diameter of the tested cable; the inner width D of the high reel (2) and the low reel (10) is equal to the outer diameter of the cable + (3 to 5) mm.

7. The high-speed mobile cable service life test method according to claim 4, characterized in that In the test simulation platform, the relationship between the inner diameter B of the high and low reels and the outer diameter r of the tested cable is: 1) When r is not greater than 25mm, the bending test is carried out with a bending radius not greater than 4 times the outer diameter r of the tested cable, then B≤8r; 2) When r is greater than 25mm, the bending test is carried out with a bending radius not greater than 6 times the outer diameter r of the cable being tested, then B≤12r.

8. The high-speed mobile cable service life test method according to claim 4 is characterized in that In the test simulation dedicated platform, the high reel (2) and the low reel (10) have the same structural dimensions.

9. The high-speed mobile cable service life test method according to claim 4, characterized in that In the test simulation dedicated platform, the rotating shaft of the high reel (2) and the rotating shaft of the low reel (10) are respectively connected to the same drive motor through a transmission mechanism; a clutch mechanism is also connected between the rotating shaft of the high reel (2) and the transmission mechanism; and a clutch mechanism is also connected between the rotating shaft of the low reel (10) and the transmission mechanism.

10. The high-speed mobile cable service life test method according to claim 9, characterized in that In the test simulation dedicated platform, the transmission mechanism includes a one-input and two-output reducer and a sprocket transmission mechanism; the input shaft of the reducer is connected to the drive motor, and the two output shafts of the reducer are respectively connected to the rotating shafts of the high and low reels through the sprocket transmission mechanism.

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