Multifunctional superconducting cable take-up and pay-off device

Abstract

The invention discloses a multifunctional superconducting cable take-up and pay-off device, and belongs to the technical field of superconducting cables, the multifunctional superconducting cable take-up and pay-off device comprises a superconducting cable reel, a movable cable reel support and a cable take-up and pay-off system, the coiling diameter of the superconducting cable reel is 1200 mm, the length of a superconducting cable capable of being coiled is 2 km, and a right tip part and a left tip part are arranged at the two ends of the movable cable reel support. The movable cable reel support is used for rapidly clamping or loosening the superconducting cable reel, and the cable winding and unwinding system is fixedly installed on the movable cable reel support and used for driving the superconducting cable reel to wind and unwind cables and providing tension needed by cable unwinding. According to the invention, the large winding radius design meets the special requirements on the vulnerability and bending radius sensitivity of the superconducting cable, and achieves the functions of automatic winding of the superconducting cable, simple transportation and disassembly, tension of cable laying and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of superconducting cables, and more particularly to a multifunctional superconducting cable retracting and releasing device. Background Art

[0002] Superconducting cables, leveraging the zero electrical resistance of superconducting materials at extremely low temperatures, enable high-capacity, low-loss power transmission. They are a key technology for addressing future challenges such as urban power grid expansion and long-distance transmission of renewable energy. However, the core of superconducting cables—superconducting tape (such as REBCO tape)—and the cable core they comprise are typically brittle, have relatively low mechanical strength, and are extremely sensitive to bending radius.

[0003] Existing cable reels are primarily designed for conventional power cables or communications cables. Their core functions are to provide winding support, facilitate transportation, and facilitate laying and payout. The drum surface of traditional cable reels is typically a rigid metal structure, lacking specialized protection for the fragility of superconducting tape. The bending stress, extrusion, friction, and vibration generated during winding, storage, and transportation can easily cause microcracks, delamination, or strand breakage in the superconducting tape, severely compromising its superconducting properties and mechanical integrity. Furthermore, the winding tension control and bend radius design of traditional cable reels often fail to meet the stringent precision bend radius requirements of superconducting cables.

[0004] In summary, existing cable reel systems, when used with superconducting cables, fail to effectively address the key challenges posed by their unique material properties (brittleness and sensitivity to bend radius): how to maximize protection from mechanical damage during the entire process of reeling, storage, and transportation, while facilitating subsequent testing and installation. This technological gap severely restricts the engineering application, operational efficiency, and cost control of superconducting cables. Therefore, designing a multifunctional superconducting cable reel is of great application value. Summary of the Invention

[0005] In view of this, the present invention provides a multifunctional superconducting cable retracting and releasing device, which can effectively protect the superconducting cable from mechanical damage during transportation, and realize automatic reeling of the superconducting cable and easy transportation and disassembly.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A multifunctional superconducting cable retraction and unwinding device comprises a superconducting cable drum, a mobile cable drum support, and a cable retraction and unwinding system. The surface of the superconducting cable drum is provided with an outer soft coating. The superconducting cable drum has a winding diameter of 1200mm and can wind a superconducting cable of 2km in length. The two ends of the mobile cable drum support are provided with a right top component and a left top component for quickly clamping or loosening the superconducting cable drum. The cable retraction and unwinding system is fixedly mounted on the mobile cable drum support and is used to drive the superconducting cable drum to retract and unwind the cable, providing the tension required for unwinding the cable.

[0007] Furthermore, the superconducting cable reel includes: circular side plates, an outer soft package, an inner cylindrical wall, a central tube, and an inner support plate. The circular side plates are fixed on both sides of the inner cylindrical wall, the outer soft package is arranged on the surface of the inner cylindrical wall, the central tube is arranged at the center of the inner cylindrical wall, and the central tube is surrounded by an inner support plate, and the inner support plate is fixedly connected to the inner cylindrical wall.

[0008] Furthermore, the superconducting cable reel also includes an annular retaining ring, an outer support plate, a triangular reinforcement plate, a top ring, a lifting eye screw and a lifting block. An annular retaining ring is fixed to the outer side of the circular side plate, and the top ring is arranged at the end of the central tube. An outer support plate is arranged around the top ring and the annular retaining ring. The outer support plates are fixed by triangular reinforcement plates. The lifting block is fixed in the interlayer formed by the circular side plate and the triangular reinforcement plate, and the lifting eye screw is fixed on the lifting block.

[0009] Furthermore, the outer soft wrapping is made of polyethylene foam and is bonded to the outer surface of the inner tube wall, and is used for buffering and shock-resistance when the superconducting cable is coiled.

[0010] Furthermore, the movable cable drum support also includes: a universal wheel, a support frame and a cable drum auxiliary support component, the universal wheel is arranged at the bottom corner of the support frame, and the cable drum auxiliary support component is installed on the support frame for auxiliary support of the superconducting cable drum.

[0011] Furthermore, the support frame includes a support base plate, vertical channel steel, transverse channel steel, inclined channel steel, and a support top plate. The vertical channel steel is fixed on the support base plate and located at both ends of the support frame. The transverse channel steel is arranged and fixed on the vertical channel steel. The bottom of the inclined channel steel on the same side is set at both ends of the vertical channel steel, and the top is fixed on the support top plate.

[0012] Furthermore, the cable drum auxiliary support component is arranged on the transverse channel steel, and the cable drum auxiliary support component includes: a support body, a screw, a nut and a support bearing. A rectangular hole is opened in the middle of the support body, and the support bearing is arranged in the rectangular hole by rotating the screw, and the two sides of the screw are fixed by nuts.

[0013] Furthermore, the right top component includes: a first telescopic mechanism and a driving mechanism, the first telescopic mechanism is arranged at the top right side of the support frame, the first telescopic mechanism includes a round nut, a screw rod, a locking screw, a top cover plate, a cover plate screw, a top bearing, an elastic retaining ring, and a top, the round nut is fixed on the right side support top plate, the screw rod is threadedly connected to the round nut, the locking screw is arranged in the round nut to lock the screw rod, the top bearing is installed at the top end of the screw rod and fixed by an elastic retaining ring, the top sleeve is arranged on the outside of the top bearing, the top cover plate is fixed to the top by the cover plate screw, the driving mechanism includes a handwheel, a flat key and a locking nut, and the handwheel is fixed to the tail end of the screw rod by the handwheel flat key and the locking nut.

[0014] Furthermore, the left top component includes a second telescopic mechanism, an active synchronous wheel, a resistance synchronous wheel and a synchronous wheel locking screw. The second telescopic mechanism has the same structure as the first telescopic mechanism and is arranged at the top left side of the support frame. The active synchronous wheel and the resistance synchronous wheel are fixed to the top of the second telescopic mechanism by the synchronous wheel locking screw.

[0015] Furthermore, the cable retraction and release system includes: a variable frequency AC motor, a synchronous pulley, a pulley key, a magnetic powder brake, and a synchronous belt. The variable frequency AC motor and the magnetic powder brake are fixed to the movable cable drum bracket by welding. The variable frequency AC motor and the magnetic powder brake are respectively connected to the synchronous pulley through the pulley key. The two synchronous pulleys on the variable frequency AC motor and the magnetic powder brake are respectively connected to the active synchronous pulley and the resistance synchronous pulley through two synchronous belts.

[0016] The beneficial effects of the present invention are as follows: the present invention meets the special requirements of superconducting cable fragility and bending radius sensitivity through the soft outer wrapping and large winding radius design on the superconducting cable reel. At the same time, through the coordinated use of the movable cable reel bracket, the cable retraction and release system and the superconducting cable reel, the superconducting cable can be automatically reeled, easily transported and disassembled, and the cable can be released with tension. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a three-dimensional diagram of a multifunctional superconducting cable retracting and releasing device of the present invention; Figure 2 is a cross-sectional view of a superconducting cable reel; Figure 3 Schematic diagram of the movable cable drum support structure; Figure 4 It is a schematic diagram of the structure of the right top component; Figure 5 It is a schematic diagram of the structure of the left top component; Figure 6 This is a schematic diagram of the structure of the auxiliary support components of the cable drum; Figure 7 It is a structural diagram of the cable retraction system; Figure 8 Schematic diagram of the assembly of superconducting cable drum and movable cable drum support; Figure 9 This is a schematic diagram of processing the end of the superconducting cable before winding the superconducting cable; Figure 10 This is a schematic diagram of the operation of the active synchronous wheel and the resistance synchronous wheel before the superconducting cable is wound; In the figure: 1. Superconducting cable drum; 101. Circular side plate; 102. Annular retaining ring; 103. Outer soft package; 104. Inner tube wall; 105. Central tube; 106. Inner support plate; 107. Outer support plate; 108. Triangular reinforcement plate; 109. Top ring; 110. Eye screw; 111. Lifting block; 2. Movable cable drum bracket; 201. Universal wheel; 202. Support bottom plate; 203. Vertical channel steel; 204. Horizontal channel steel; 205. Oblique channel steel; 206. Support top plate; 3. Right top component; 301. Round nut; 302. Screw; 303. Locking screw; 304. Hand Wheel; 305, handwheel flat key; 306, locking nut; 307, top cover; 308, cover screw; 309, top bearing; 310, elastic retaining ring; 311, top; 4, left top component; 401, active synchronous wheel; 402, resistance synchronous wheel; 403, synchronous wheel locking screw; 5, cable drum auxiliary support component; 501, support body; 502, screw; 503, nut; 504, support bearing; 6, cable retraction and release system; 601, variable frequency AC motor; 602, synchronous wheel; 603, pulley key; 604, magnetic powder brake; 605, synchronous belt; 7, superconducting cable. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0019] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "horizontal", "inner", "outer", "one side", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or components referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes and should not be understood as indicating or implying relative importance. In addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or a circuit connection; it can be a direct connection, an indirect connection through an intermediate medium, or it can be internal communication between two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0020] Example 1

[0021] like Figure 1-10 As shown, the present invention discloses a multifunctional superconducting cable winding and releasing device, including a superconducting cable reel 1, a movable cable reel support 2 and a cable winding and releasing system 6. The superconducting cable reel 1 is used for winding and storing superconducting cables. Its winding area is soft-wrapped to protect the superconducting cable. Due to the characteristic that superconducting cables cannot be bent with a small radius, the winding diameter of the superconducting cable reel 1 is set to 1200 mm, and the superconducting cable can be wound with a length of about 2 km. The movable cable reel support 2 is provided with a right top component 3 and a left top component 4 at both ends for quickly clamping or loosening the superconducting cable reel 1. The cable winding and releasing system 6 is fixedly installed on the movable cable reel support 2, and provides winding power and unwinding tension when the superconducting cable reel 1 winds and unwinds the superconducting cable, respectively.

[0022] The superconducting cable reel 1 comprises circular side panels 101, an outer soft coating 103, an inner cylindrical wall 104, a central tube 105, and an inner support plate 106. The circular side panels 101 are fixed to either side of the inner cylindrical wall 104. The outer soft coating 103 is mounted on the surface of the inner cylindrical wall 104. In this embodiment, the outer soft coating 103 is made of polyethylene foam and bonded to the outer surface of the inner cylindrical wall 104, providing cushioning and vibration resistance during superconducting cable coiling. The central tube 105 is positioned at the center of the inner cylindrical wall 104. An inner support plate 106 surrounds the central tube 105 and is fixedly connected to the inner cylindrical wall 104.

[0023] As a preferred embodiment of the present invention, the superconducting cable reel 1 further includes an annular retaining ring 102, an outer support plate 107, a triangular reinforcement plate 108, a top ring 109, a lifting eye screw 110 and a lifting block 111. The annular retaining ring 102 is fixed to the outer side of the circular side plate 101, the top ring 109 is arranged at the end of the central tube 105, the outer support plate 107 is arranged around the top ring 109 and the annular retaining ring 102, and the outer support plates 107 are fixed by the triangular reinforcement plate 108. The lifting block 111 is fixed in the sandwich formed by the circular side plate 101 and the triangular reinforcement plate 108, and the lifting eye screw 110 is fixed on the lifting block 111.

[0024] As a preferred embodiment of the present invention, Figure 9 As shown, a circle of superconducting cable 7 is wound on the outer soft package 103 of the superconducting cable drum 1 and a plastic wrap is wrapped around the outer surface of the circle of superconducting cable, thereby constraining the winding starting end of the superconducting cable.

[0025] The mobile cable drum support 2 also includes: a universal wheel 201, a support frame and a cable drum auxiliary support component 5. The universal wheel 201 is set at the bottom corner of the support frame, and the cable drum auxiliary support component 5 is installed on the support frame for auxiliary support of the superconducting cable drum 1.

[0026] The support frame includes a support base plate 202, a vertical channel steel 203, a horizontal channel steel 204, an inclined channel steel 205, and a support top plate 206. The vertical channel steel 203 is fixed on the support base plate 202 and is located at both ends of the support frame. The horizontal channel steel 204 is arranged and fixed on the vertical channel steel 203. The bottom of the same-side inclined channel steel 205 is set at both ends of the vertical channel steel 203, and the top is fixed on the support top plate 206.

[0027] The cable drum auxiliary support component 5 is set on the transverse channel steel 204. The cable drum auxiliary support component 5 includes: a support body 501, a screw 502, a nut 503 and a support bearing 504. A rectangular hole is opened in the middle of the support body 501. The support bearing 504 is rotated and set in the rectangular hole by the screw 502. The two sides of the screw are fixed by nuts 503.

[0028] The right top component 3 includes: a first telescopic mechanism and a driving mechanism. The first telescopic mechanism is arranged at the top right side of the support frame. The first telescopic mechanism includes a round nut 301, a screw rod 302, a locking screw 303, a top cover plate 307, a cover screw 308, a top bearing 309, an elastic retaining ring 310, and a top 311. The round nut 301 is fixed on the right side support top plate 206, the screw rod 302 is threadedly connected to the round nut 301, the locking screw 303 is arranged in the round nut 301, and is used to lock the screw rod 302. The top bearing 309 is installed at the top end of the screw rod 302 and is fixed by the elastic retaining ring 310. The top 311 is sleeved on the outside of the top bearing 309, and the top cover plate 307 is fixed to the top 311 by the cover screw 308. The driving mechanism includes a handwheel 304, a flat key 305 and a locking nut 306. The handwheel 304 is fixed to the tail end of the screw rod 302 by the handwheel flat key 305 and the locking nut 306.

[0029] The left top component 4 includes a second telescopic mechanism (with the same structure as the first telescopic mechanism), an active synchronous wheel 401, a resistance synchronous wheel 402 and a synchronous wheel locking screw 403. The second telescopic mechanism is arranged at the top left side of the support frame, and the active synchronous wheel 401 and the resistance synchronous wheel 402 are fixed to the top 311 of the second telescopic mechanism through the synchronous wheel locking screw 403.

[0030] Preferably, if Figure 8 As shown, turning the handwheel 304 on the movable cable drum support 2 increases the distance between the left and right end points 311, facilitating the placement of the superconducting cable drum 1. Using a lifting device, the superconducting cable drum 1 is hoisted into the movable cable drum support 2 using the eyebolts 110 on both ends of the superconducting cable drum 1. The inner hole of the left top ring 109 of the superconducting cable drum 1 contacts the left end point 311 of the movable cable drum support 2. Tightening the locking screw 303 on the left round nut 301 secures the left side of the superconducting cable drum 1. Reversely turning the handwheel 304 causes the right end point 311 to press against the right top ring 109 of the superconducting cable drum 1. Tightening the locking screw 303 on the right round nut 301 secures the ends of the superconducting cable drum 1, while simultaneously supporting the bottom of the superconducting cable drum with the auxiliary support member 5.

[0031] The cable retraction and retraction system 6 includes: a variable frequency AC motor 601, a synchronous pulley 602, a pulley key 603, a magnetic powder brake 604, and a synchronous belt 605. The variable frequency AC motor 601 and the magnetic powder brake 604 are fixed to the movable cable drum bracket 2 by welding. The variable frequency AC motor 601 and the magnetic powder brake 604 are respectively connected to the synchronous pulley 602 through the pulley key 603. The two synchronous pulleys 602 on the variable frequency AC motor 601 and the magnetic powder brake 604 are respectively connected to the active synchronous pulley 401 and the resistance synchronous pulley 402 through two synchronous belts 605.

[0032] Preferably, if Figure 10As shown, tighten the synchronous wheel locking screw 403 on the active synchronous wheel 401 to enable the variable frequency AC motor 601 to effectively transmit the required winding power. Unscrew the synchronous wheel locking screw 403 on the resistance synchronous wheel 402 to prevent the magnetic powder brake 604 from being activated by the active rotation of the superconducting cable drum 1. Power on the variable frequency AC motor 601, and the main shaft of the variable frequency AC motor 601 rotates, driving the rotation of the superconducting cable drum 1 via the synchronous belt 605, thereby actively winding the superconducting cable.

[0033] Preferably, after the superconducting cable is wound up, it can be rolled by the universal wheels 201 on the movable cable drum support 2 to facilitate the transportation of the superconducting cable.

[0034] Preferably, when testing the superconducting cable, the lifting device is used to lock the eye screws 110 at both ends of the superconducting cable drum 1, and the hand wheel 304 is rotated to separate the right top ring 311 from the right top ring 109, so that the superconducting cable drum 1 can be lifted out for testing and other work.

[0035] After testing the superconducting cable, it is preferably placed again on the movable cable drum support 2 for cable payout and magnet winding. Tighten the synchronous wheel locking screw 403 on the resistance synchronous wheel 402 to ensure that the magnetic powder brake 604 can effectively transmit the resistance, or tension, required for cable payout. Unscrew the synchronous wheel locking screw 403 on the active synchronous wheel 401 to prevent the variable-frequency AC motor 601 from rotating during cable payout. Connect the power supply to the magnetic powder brake 604, causing its main shaft to rotate and transmit the required tension for the superconducting cable payout via the synchronous belt 605.

[0036] The present invention can be used to automatically wind up superconducting cables and provide cable-releasing tension, meeting special requirements for superconducting cables in terms of fragility and bending radius sensitivity, facilitating the transportation and testing of superconducting cables, and having reference value for the engineering application, operation and maintenance efficiency, and cost control of superconducting cables.

[0037] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A multifunctional superconducting cable retracting and releasing device, characterized in that: The invention comprises a superconducting cable drum (1), a movable cable drum support (2) and a cable retracting and releasing system (6). The surface of the superconducting cable drum (1) is provided with an outer soft package (103). The superconducting cable drum (1) has a coiling diameter of 1200 mm and can coil a superconducting cable of 2 km in length. The movable cable drum support (2) is provided with a right top component (3) and a left top component (4) at both ends for quickly clamping or releasing the superconducting cable drum (1). The cable retracting and releasing system (6) is fixedly mounted on the movable cable drum support (2) and is used for driving the superconducting cable drum (1) to retract and release the cable and provide the tension required for releasing the cable.

2. A multifunctional superconducting cable retracting and releasing device according to claim 1, characterized in that: The superconducting cable reel (1) comprises: circular side plates (101), an inner cylindrical wall (104), a central tube (105), and an inner support plate (106); the circular side plates (101) are fixed on both sides of the inner cylindrical wall (104); the outer soft package (103) is arranged on the surface of the inner cylindrical wall (104); the central tube (105) is arranged at the center of the inner cylindrical wall (104); the central tube (105) is surrounded by an inner support plate (106); and the inner support plate (106) is fixedly connected to the inner cylindrical wall (104).

3. A multifunctional superconducting cable retracting and releasing device according to claim 2, characterized in that: The superconducting cable drum (1) further comprises an annular retaining ring (102), an outer support plate (107), a triangular reinforcement plate (108), a top ring (109), a lifting eye screw (110) and a lifting block (111), wherein an annular retaining ring (102) is fixed to the outer side of the circular side plate (101), the top ring (109) is arranged at the end of the central tube (105), an outer support plate (107) is arranged between the top ring (109) and the annular retaining ring (102), the outer support plates (107) are fixed to each other by the triangular reinforcement plate (108), the lifting block (111) is fixed in the sandwich formed by the circular side plate (101) and the triangular reinforcement plate (108), and the lifting eye screw (110) is fixed on the lifting block (111).

4. The multifunctional superconducting cable retracting and releasing device according to claim 2, characterized in that: The outer soft package (103) is made of polyethylene foam and is bonded to the outer surface of the inner tube wall (104) and is used for buffering and shock resistance when the superconducting cable is coiled.

5. The multifunctional superconducting cable retracting and releasing device according to claim 1, characterized in that: The movable cable drum support (2) further comprises: a universal wheel (201), a support frame, and a cable drum auxiliary support component (5); the universal wheel (201) is arranged at a bottom corner of the support frame; the cable drum auxiliary support component (5) is mounted on the support frame and is used for auxiliary support of the superconducting cable drum (1).

6. The multifunctional superconducting cable retracting and releasing device according to claim 5, characterized in that: The support frame comprises a support base plate (202), vertical channel steels (203), transverse channel steels (204), oblique channel steels (205), and a support top plate (206), wherein the vertical channel steels (203) are fixedly arranged on the support base plate (202) and located at both ends of the support frame, the transverse channel steels (204) are arranged and fixed on the vertical channel steels (203), and the bottoms of the oblique channel steels (205) on the same side are arranged at both ends of the vertical channel steels (203), and the tops are fixed on the support top plate (206).

7. The multifunctional superconducting cable retracting and releasing device according to claim 5, characterized in that: The cable drum auxiliary support component (5) is arranged on the transverse channel steel (204), and the cable drum auxiliary support component (5) comprises: a support body (501), a screw rod (502), a nut (503) and a support bearing (504). A rectangular hole is opened in the middle of the support body (501), and the support bearing (504) is rotatably arranged in the rectangular hole through the screw rod (502). Both sides of the screw rod (502) are fixed by nuts (503).

8. The multifunctional superconducting cable retracting and releasing device according to claim 6, characterized in that: The right top component (3) includes: a first telescopic mechanism and a driving mechanism, wherein the first telescopic mechanism is arranged at the top right side of the support frame, and the first telescopic mechanism includes a round nut (301), a screw rod (302), a locking screw (303), a top cover plate (307), a cover screw (308), a top bearing (309), an elastic retaining ring (310), and a top (311), wherein the round nut (301) is fixed on the right support top plate (206), the screw rod (302) is threadedly connected to the round nut (301), and the locking screw (303) is arranged on the round nut (301). The nut (301) is used to lock the screw (302), the top bearing (309) is installed on the top of the screw (302) and fixed by an elastic retaining ring (310), the top (311) is sleeved on the outside of the top bearing (309), the top cover (307) is fixed to the top (311) by a cover screw (308), and the driving mechanism includes a handwheel (304), a flat key (305) and a locking nut (306), and the handwheel (304) is fixed to the tail end of the screw (302) by the handwheel flat key (305) and the locking nut (306).

9. The multifunctional superconducting cable retracting and releasing device according to claim 8, characterized in that: The left top component (4) comprises a second telescopic mechanism, an active synchronous wheel (401), a resistance synchronous wheel (402) and a synchronous wheel locking screw (403); the second telescopic mechanism has the same structure as the first telescopic mechanism and is arranged at the top left of the support frame; the active synchronous wheel (401) and the resistance synchronous wheel (402) are fixed to the top (311) of the second telescopic mechanism via the synchronous wheel locking screw (403).

10. The multifunctional superconducting cable retracting and releasing device according to claim 9, characterized in that: The cable retracting and releasing system (6) comprises: a variable frequency AC motor (601), a synchronous wheel (602), a pulley key (603), a magnetic powder brake (604), and a synchronous belt (605). The variable frequency AC motor (601) and the magnetic powder brake (604) are fixed to the movable cable drum support (2) by welding. The variable frequency AC motor (601) and the magnetic powder brake (604) are respectively connected to the synchronous wheel (602) via the pulley key (603). The two synchronous wheels (602) on the variable frequency AC motor (601) and the magnetic powder brake (604) are respectively connected to the active synchronous wheel (401) and the resistance synchronous wheel (402) via two synchronous belts (605).

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