KR101484922B1 - Method of inserted cable type high voltage bushing for a pole transformer - Google Patents

Abstract

The present invention relates to a method to manufacture a cable-integrated type high voltage bushing for a pole transformer. The method to manufacture a cable-integrated type high voltage bushing (20) for a pole transformer, which is a connecting member installed on the lid (11) of a pole transformer (1) and applies high voltage power supplied from the outside to wires, includes: an insulating tube (21) of a cylindrical shape which has a hollow part (21a) formed inside; a connector (23) which is fixated on the inside of the hollow part (21) of the insulating tube (21) and is connected to a copper rod (26) in order to be electrically connected to the inside of the pole transformer (1); and a clamp (24) which is assembled to be fixated on the upper end of the insulating tube (21) in order to connect a cable (27) in a state of being combined with the connector (23). The method: assembles and prepares the screw axis (23c) of the connector (23) to protrude toward the upper end part of the insulating tube (21) by inserting the connector (23) into the insulating tube (21) while compressing and fixating an end of the cable (27), which is prepared by cutting the cable at a predetermined length, to a cable connecting part (24b) of the clamp (24); assembles the clamp (24) by screw-combining the clamp (24) with the screw axis (23c); coats the outer circumference surface of the insulating tube (21) and the outer circumference surface of the clamp (24) with adhesive while removing moisture and dries for predetermined time; and covers the outer circumference surface of the insulating tube (21) and the outer circumference surface of the clamp (24) with an insulating housing (22) of a polymer material by injection molding by using an injection machine.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a high voltage bushing for a pneumatic transformer,

The present invention relates to a method of manufacturing a high-voltage bushing integrated with a cable for a pneumatic transformer, and more particularly, to a method of manufacturing a high-voltage bushing with a high-pressure bushing used for a pneumatic transformer, The present invention provides a manufacturing method by injection molding in which an outer circumferential surface of a clamp and a pipe are integrated by injection molding into an insulating housing so that a connection operation can be performed without using an insulating cover for bushing in the process of installing a pillar transformer, It is possible to maintain the airtightness between the cut-out switch and the pneumatic transformer and to prevent the occurrence of tracking accidents due to unevenness of the fastening method by the operator when connecting the cable between the cut-out switch and the high-pressure bushing The present invention relates to a method of manufacturing a high-voltage bushing integrated with a cable for a pneumatic transformer.

Generally, the power supplied from a substation to a high voltage (22,900V) is converted and supplied to a low voltage that can be used in general consumers such as homes and industrial sites through a transformer.

In this case, a transformer is a generic term for a device that changes an alternating voltage and a current value by an electromagnetic induction action. In particular, as described above, a high-voltage power supplied from a substation is converted into a low- , Which is usually fixedly installed on a pole or the like.

Although the structure of such a pillar transformer may show a difference depending on the capacity and the voltage, it generally includes a winding wire and an iron core for performing the function of the transformer, and these windings and the iron core are disposed in a tank This insulating oil prevents the moisture and dust from penetrating into the insulating material of the winding, thereby lowering the dielectric strength. In addition, it serves to dissipate the heat generated by the iron core or the coil by convection and radiation of the oil.

The construction of such a typical pillar transformer is shown in Fig.

As shown in FIG. 1, the punch transformer 100 includes a box-shaped enclosure 110, a lid 120 for enclosing the box-shaped enclosure 110, and a connecting member 130 for applying a high- Pressure bushing 130 (or "primary bushing") installed through the lid 120 and a low-pressure bushing 130 installed on the outer wall of the enclosure 110 to draw out the transformed low- (140, or "secondary bushing").

At this time, the inside of the enclosure 110 of the pillar transformer 100 is filled with insulating oil so as to cool the heat generated at the time of transforming.

In addition, the high-voltage bushing 130 can insulate a high voltage of a bare wire part with a sufficient supporting force to support the electric wire as well as having sufficient electrical insulation strength, (Insulators) having excellent heat resistance and corrosion resistance are mainly used in order to prevent the dielectric strength from deteriorating when the dust or the like is adhered. Recently, as the polymer synthesis technology has been developed, the high pressure bushing 130 Polymer rubber or polymer materials such as EPDM (ethylene propylene rubber), XLPE, epoxy and silicone rubber are used as materials.

Here, the high-voltage bushing 130 coupled to the pneumatic transformer 100 has already been widely used.

For example, it is disclosed in Korean Registered Utility Model No. 0282453 (published on July 19, 2002), Registered Patent Publication No. 0632247 (issued October 10, 2006), Registered Patent Publication No. 0951473 (issued on April 7, 2010) The technology related to the transformer bushing is described in the publication No. 1118968 (Notice of Feb.28, 2012), the Registered Utility Model No.0460375 (Notice of Feb.21, 2012), the Registration Utility Utility Model No. 0462698 (Notice of September.24, 2012) Lt; / RTI >

2 shows an embodiment of a conventional high-pressure bushing for a pillar transformer.

2, the high-voltage bushing 130 connects the cable 170 (see FIG. 3) to apply the high-voltage power supplied from the outside in the punching transformer 100 to the windings inside the main-voltage transformer 100 .

The high pressure bushing 130 is installed in the transformer and has a hollow portion 132 formed therein. The high pressure bushing 130 is fixed to the inside of the insulator 131 while being electrically connected to the transformer, A connector 133 extending to the upper portion of the insulator 131 and a screw terminal 134 connected to the screw shaft 134 of the connector 133 and having a connection terminal 136 on the upper surface thereof, And a terminal clamp 135 in the form of a cap.

At this time, the connector 133 electrically connects the enclosing pipe 137 (or bare wire) inside the transformer with the connecting terminal 136.

The connector 133 is a rod-like conductor having a flange portion at a central portion thereof. The upper side of the connector 133 is connected to the connection terminal 136 of the terminal clamp 135 with respect to the flange of the connector 133, And the lower side thereof is joined by soldering, pressing or bolt assembly, welding, or the like.

The connection terminal 136 is integrally formed with a cap-shaped terminal clamp 135 that is screwed to the screw shaft 134 and covers the upper end of the insulator 131.

When the high-pressure bushing 130 having such a configuration is coupled to the punching transformer 100 (see FIG. 1), the insulating oil filled in the punching transformer 100 flows into the hollow portion 132 of the insulator 131 The connector 133 is hermetically sealed between the terminal clamp 135 and the upper end surface of the insulator 131 and the upper surface of the flange portion of the connector 133. At this time, Shaped packings 138 and 139 for holding and engaging, respectively.

The packing 138 prevents the insulating oil introduced into the insulator 131 from leaking to the through hole of the insulator 131 together with the terminal clamp 135 and prevents damage to the insulator 131 .

In order to assemble the conventional high-voltage bushing 130 with the pneumatic transformer 100, the high-voltage bushing 130 having the above-described structure must be connected to the punching transformer 100, The connector 133 and the terminal clamp 135 of the high-pressure bushing 130 are separately assembled and assembled in the process of assembling and installing the high-voltage bushing 130. Thus, unnecessary work flow occurs, There is a disadvantage that the packing 138 needs to be performed between the clamps 135 in order to maintain airtightness.

Particularly, when assembling the terminal clamp 135, there is a possibility that leakage occurs when the assembling method is uneven and the airtightness is deteriorated according to each worker. When the defects arise due to the assembly failure, the pole transformer needs to be replaced Therefore, there is a disadvantage that the exchange cost is incurred thereby leading to economic loss.

The pneumatic transformer 100 provided with the high-pressure bushing 130 as described above is installed in a pole 150 installed at a position separated from a building such as a residential building as shown in FIG.

3, the pillar transformer 100 is installed at a predetermined position of the electric pole 150, the cut-out switch 160 is installed above the pillar transformer 100, The cutout switch 160 is connected to the primary side high-voltage bushing 130 of the transformer 100 through a cable 170 so as to protect the pillar transformer 100 from overvoltage and fault current, .

The cut-out switch 160 is connected to the primary side high-voltage bushing 130 of the pillar-type transformer 100 to allow fuses (not shown) to be fused when an overload or a fault current is applied, It is intended to protect transformers from accidents such as shorts.

As described above, the cut-out switch (COS) 160 protects the transformer by preventing destruction and breakage of the transformer due to overload or failure of the transformer by attaching to the primary side of the pneumatic transformer and the high-voltage charge- And is an overcurrent cutoff device used for opening and closing a line of a transformer.

At this time, professional installation work is required to install the pillar transformer 100 in the electric pole 150 and to connect it to the cut-out switch 160.

That is, a connection and disconnection process of the conventional pillar transformer 100 and the cut-out switch 160 will be schematically described below.

3, when the pneumatic transformer 100 is installed using the equipment in the electric pole 150, it is possible to connect the cut-out switch 160 (COS), which is a safety device, from the installed pneumatic transformer 100 The cable 170 is cut and prepared.

The cable 170 is peeled off the cable 170 so that it can be easily connected to the connection terminal 136 of the pole clamp 135 of the pillar transformer 100 and the clamp of the cut-out switch 160, COS.

Then, the connection terminal 136 of the terminal clamp 135 of the high-voltage bushing 130, which is the primary side of the pneumatic transformer 100, is loosened using a tool so that the cable 170 can be connected.

Then, an insulation cover (not shown) for the transformer bushing according to the standard is inserted into the high-voltage bushing 130 on the primary side of the pillar transformer in order to prevent foreign matter and moisture infiltration.

In this state, the cable 170 for connection of the cut-out switch is connected to the connection terminal 136 of the terminal clamp 135 by using a tool to the pneumatic transformer-side high-voltage bushing 130.

When the cable 170 is connected, the insulating cover for the bushing prepared in the high-voltage bushing 130 on the primary side of the pillar transformer 100 is tightly taped using insulating tape so that rainwater does not enter the insulating cover.

Then, the cable 170 connected to the pneumatic transformer 100 is connected to the cut-out switch 160 (COS) using a tool.

However, the problem in the step of installing the pneumatic transformer is that the unevenness of the clamp tightening torque due to the difference in the working method of each worker may cause a disconnection accident due to the occurrence of tracking of the connecting portion.

 Since there is a difference in the method of assembling the insulating cover for bushing to the pillar transformer for each field worker, there is a possibility that an accident may occur due to deterioration of the charging part due to foreign matter penetration and moisture penetration due to exposure of the live part.

Especially, in case of working in the field, use the dedicated work vehicle to prepare and cover the cable in the air, clamp work 2 times (pillar transformer side, cutout switch side), insulation cover work for bushing, insulating cover taping work, There is a disadvantage that the labor is greatly increased.

Korea Registered Utility Model No.0282453 (High voltage bushing fixing device of pillar transformer) Korean Registered Utility Model No.0460375 (Bulletin of May 21, 2012, Name: Primary bushing sealing structure of pillar transformer) Korean Patent Publication No. 0632247 (published on October 9, 2006, name: bushing for transformer) Korean Registered Patent Publication No. 0951473 (April 7, 2010, name: bushing for transformer) Korean Registered Patent No. 1118968 (issued Feb. 28, 2012, name: bushing for transformer) Registered Utility Model No.0462698 of Korea Register (September 24, 2012, name: bushing for pole transformer)

Accordingly, the present invention has been researched and developed in order to solve various problems caused by assembling a cable between the high-voltage bushing and the cut-out switch in the process of installing the conventional pillar-form transformer.

That is, an object of the present invention is to provide an injection molding machine and a method of manufacturing the same, which are capable of manufacturing a high-pressure bushing used in a punching transformer, a cable for connecting a cut- By providing the manufacturing method through molding, it is possible to connect the transformer without using the insulating cover for the first bushing in the process of installing the punch transformer, thereby making it possible to drastically reduce the material cost and work flow, A method of manufacturing a high-voltage bushing integrated with a cable for pneumatic transformer that can keep airtightness between transformers and prevent tracking accidents due to unevenness of fastening method by operator when connecting cables between cutout switch and high pressure bushing .

According to an aspect of the present invention, there is provided a connecting member for supplying a high-voltage power supplied from the outside through a coil, the connecting member being provided on a cover of a pillar transformer, And a clamp which is fixed to the inside of the hollow portion of the pipe to be electrically connected and is connected and fixed to the upper end of the pipe so that the cable can be connected to the connector when the pipe is coupled to the connector, The method of manufacturing a high-pressure bushing for a high-pressure bushing according to claim 1, wherein the cable is cut to a predetermined length, and one end of the cable is inserted into the cable connection portion of the clamp, And a clamp is screwed to the screw shaft to form a screw And an insulating housing made of a polymer material is wrapped by an injection molding on the outer circumferential surface of the pipe and the clamp using an injection molding machine, A method of manufacturing a high-pressure bushing with a cable for a cable is provided.

Here, the clamp used to integrally connect the cable includes a clamp body portion formed with a screw hole in the downward direction, and a cable connection portion protruding upward from the clamp body portion to connect the cable, And a conductor connecting groove having a diameter relatively narrower than that of the cable receiving groove and extending in the inward direction and capable of fitting a conductor portion in which the covering member of the cable is peeled off is formed Structure is preferably used.

At this time, it is preferable that a packing member for preventing oil leakage is inserted into the screw shaft and mounted on the upper surface of the pipe before mounting the clamp on the screw shaft.

After completing the high-pressure bushing by injection-molding an insulation housing made of a polymer material on the outer circumferential surface of the pipe and the clamp, it is preferable to seal and finish the cable end portion and the clamp injection portion.

According to the present invention, since the cable is integrally fixed to the high-voltage bushing installed in the punching transformer during the manufacturing process of the high-pressure bushing through the injection molding, it is possible not only to greatly reduce the work flow at the punching transformer installation site, It is possible to prevent various problems that may occur when the cable is assembled with the cable.

That is, according to the present invention, a high-pressure bushing in which an outer circumferential surface of an aileron and a clamp are injection-molded by an insulating housing in a state where a cable is integrally fixed to a clamp in the process of manufacturing a high-pressure bush is installed in a punch transformer, Since it is not necessary to assemble the cable to the high-pressure bushing when connecting the cable with the cut-out switch after installing it on the pole, a separate tightening work by the operator is not necessary, It is possible to prevent a tracking accident that may occur due to a tightening operation.

In addition, since the cable is assembled to the high-pressure bushing in a state that the cable is enclosed in the insulating housing by the integral injection method according to the present invention, there is an advantage that foreign matter and moisture penetration can be prevented originally through the cable fastening part.

In addition, since it is not necessary to use an insulating cover for bushing to seal the high-pressure bushing as in the prior art, it is not necessary to use the taping operation using insulating tapes, The number of assembling processes due to the omission of the work process can be greatly reduced.

In addition, according to the present invention, since the oil leakage preventing function is provided through the insulating housing and the packing member, the leakage preventing function is relatively enhanced as compared with the conventional high pressure bushing.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing a conventional configuration of a pillar transformer according to the prior art; Fig.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pneumatic transformer, and more particularly,
FIG. 3 is an exemplary view showing a state in which a pillar-type transformer installed in a pole and a cut-out switch are connected by a cable according to the related art.
4 is a view showing a pillar-shaped transformer having a cable integral type high-pressure bushing according to the present invention.
5 is a schematic cross-sectional view showing the construction of a cable-integrated high-pressure bushing according to the present invention.
FIG. 6 is a view showing a separated state of a cable and a clamp according to the present invention before coupling. FIG.
Fig. 7 is a view showing a state where the cable according to the present invention is crimped to the clamp. Fig.
FIG. 8 is a process block diagram schematically illustrating a manufacturing process of a cable-integrated high-voltage bushing for a pneumatic transformer according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In order to explain the preferred embodiments of the present invention, the thicknesses of the lines and the sizes of the components shown in the attached drawings may be exaggerated or omitted for clarity and convenience of description, Terms to be given are terms defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator.

4 to 6, a cable-integrated high voltage bushing 20 for a pneumatic transformer according to the present invention includes a main pipe 21, an insulating housing 22, a connector 23, a clamp 24, A member 25, an enclosed cable 26 (or a stranded wire), and a cable 27.

In the polymer type high-pressure bushing 20 according to the present invention, the cable 27 is assembled and fixed to the clamp 24 of the high-pressure bushing 20, and the clamp 24 is fixed to the connector Molded in such a manner that the outer circumferential surface of the eyelet 21 and the clamp 24 can be insulated by the insulating housing 22 made of a polymer material in this state, Thereby providing a method by which the bushing 20 can be manufactured.

In particular, the cable-integrated high-pressure bushing 20 manufactured as described above is installed on the upper lid 11 of the punching transformer 1. [

The pillar transformer 1 includes a box-like enclosure 10, a lid 11 for sealing the box-like enclosure 10, and a high-voltage power supply And a low pressure bushing 30 installed on the outer wall of the enclosure 10 to draw out the transformed low-pressure power to the outside And the inside of the enclosure 10 is filled with insulating oil so as to cool the heat generated at the time of transforming.

Therefore, when the pole-type transformer 1 is installed on the pole, the polymer-type high-voltage bushing 20, in which the cable 50 is integrally assembled as described above, is installed on the pole-type transformer 1. Thus, The operation of assembling the cable 170 to the high-voltage bushing 130 as described in the prior art of FIG. 3 in the process of connecting the high-voltage bushing 20 of the pneumatic transformer 1 with the cable (COS) You can get rid of it.

 Hereinafter, the structure of the high-pressure bushing manufactured according to the present invention will be described in detail before the manufacturing process of the high-pressure bushing.

5, the polymer-type high-pressure bushing 20 according to the present invention is mainly composed of an apron 21, an insulating housing 22, a connector 23, a clamp 24, a packing member 25, (26, or a twisted wire), and a cable (27).

The high-pressure bushing 20 according to the present invention having the above-described structure is a polymer-type bushing, and the aerator tube 21 is a cylindrical tube body having a hollow portion 21a forming the inside of the bushing, Injection plastics are mainly used as materials, and magnetic materials may be used in some cases.

The outer circumferential surface of the pipe 21 is wrapped by injection molding so as to be insulated by an insulating housing 22 made of a polymer material.

The insulating housing 22 is an insulating member that surrounds the outer circumferential surface of the pipe 21 through injection molding and is made of polymer rubber or polymers such as EPDM (ethylene propylene rubber), XLPE, epoxy, It is made of material.

The connector 23 is a bar-shaped conductor having flange portions 23a and 23b formed on the central and lower ends thereof. A screw shaft 23c is formed on the upper side of the flange portion 23a at the center of the connector 23, And the enclosing member 26 is joined to the lower side of the lower end flange portion 23b by soldering, pressing or bolt assembly or welding.

5 to 7, the lower side of the clamp 24 can be connected to the screw shaft 23c of the connector 23, and the upper side of the clamp 24 can be connected to the cable 27 for connecting the cut- It is made of brass or copper or aluminum, and has a cap shape that turns the funnel roughly upside down.

In other words, the clamp 24 according to the present invention has a clamp body portion 24a having a shape of a downward bulge in which a screw hole 24c is formed in a downward direction, and the clamp body portion 24a, And a cable connection part 24b protruding upward from the upper side of the cable connection part 24 and capable of connecting the cable 27.

6 and 7, the cable connecting portion 24b is formed in an octagonal columnar shape so as to protrude from the cable body portion 24a. Inside the cable connecting portion 24b, a cover 27a of the cable 27 And a conductor 27b having a relatively narrow diameter as compared with the cable receiving groove 24d and extending inward to peel off the cover 27a of the cable 27, And a circular conductor connecting groove 24e is formed in the cable connecting portion 24b so that one end of the cable 27 is inserted into the cable connecting portion 24b, have.

The cable receiving groove 24d is formed to have a predetermined depth and include a flow clearance portion that forms a slant surface so that the cable 27, which is the pressed portion, can be protected against the wind pressure of the cable 27 or the fluctuation during the operation, The surface of the edge of the groove 24d or the like is configured to maintain a rounded shape and to alleviate parts of the electric field such as a partial discharge concentrated beforehand.

It is preferable that the conductor coupling groove 24e is formed in a truncated conical shape which is tapered so as to have a larger diameter from the lower part to the upper part.

Notch grooves 24f are formed on the surface of the clamp 24 along the circumferential direction. The notch grooves 24f are formed of an insulating housing 22 made of a polymer material. The notches 21f and the clamps 24 And the insulating housing 22 is injected during the injection molding so as to increase the adhesive force.

The packing member 25 is inserted into the screw shaft 23c protruding between the clamp 24 and the upper end surface of the aerator pipe 21 in a disc shape to maintain airtightness to prevent leakage.

That is, the insulating oil filled in the pillar-shaped transformer 1 flows into the hollow portion 21a of the aerator pipe 21 to cool the enclosed pipe 26 and the connector 23, And prevents leakage to the through-hole of the screw shaft 23c, which is assembled through the surface, and also prevents damage to the auxiliary pipe 21.

The packing member 25 is preferably made of acrylonitrile butadiene rubber (NBR), which is also called nitrile rubber, which has oil resistance.

Particularly, in the present invention, the insulating housing 22 integrally surrounds the outer circumferential surface of the apt pipe 21 and the clamp 24 and is injection-molded without the mounting of the packing member 25 on the upper surface of the apt pipe 21 , The leakage preventing function can be performed by the insulating housing 22. However, by additionally inserting the packing member 25, a function of preventing double leakage can be provided to provide a more stable leakage preventing measure will be.

On the other hand, reference numeral 28 shown in Fig. 5 denotes a packing member 28 which is attached and held between the connector 21 and the connector 23 to maintain the airtightness.

The manufacturing process of the cable-integrated high-pressure bushing 20 having the above-described structure will be described with reference to the process block diagram shown in FIG.

First, a cable 27, which can be connected between a cut-out switch (not shown) and the high-pressure bushing 20, is prepared by cutting a certain length. As shown in FIG. 6, a cover 27a of the cable 27, And the portion of the conductor 27b is inserted into the cable connecting portion 24b of the clamp 24.

The portion of the conductor 27b of the cable 27 is inserted into the conductor coupling groove 24e of the clamp 24 and the portion of the cover 27a of the cable 27 is closely inserted into the cable receiving groove 24d do.

In this state, the cable 27 is firmly fixed to the clamp 24 by pressing the octagonal-shaped cable connecting portion 24b in an octagon.

The connector 23 having the enclosed member 26 is inserted into the hollow portion 21a of the aerator 21 so that the screw shaft 23c of the connector 23 is inserted into the hollow 21a of the aerator 21, When assembled and assembled, the packing member 25 is inserted into the screw shaft 23c and mounted on the upper surface of the aerator 21 to assure airtightness.

The clamp 24 integrally fixed with the cable 27 is assembled to the screw shaft 23c protruding from the upper end surface of the pipe 21 through a screw connection.

When the cap 21 and the clamp 24 are assembled together, they are dried for a certain period of time in order to remove moisture.

The dried product is subjected to an injection molding operation so that the outer surface of the dried product can be insulated by the insulating housing 22 made of a polymer material. In the preparation work for the injection molding operation, a cable 27, And the molding material of the polymer is completely fused during the injection molding.

It is preferable to apply an adhesive for preventing the interface to the surface of the cap 21 and the clamp 24.

When the preliminary preparation is completed, an injection molding operation is performed to form a shade portion protruding from the insulating housing 22 by a direct injection method with respect to the outer peripheral surface of the dried eye tube 21 and the clamp 24.

When the cable integral type high pressure bushing 20 is completed through the injection molding operation, the end of the cable 27 and the injection part of the clamp 24 are sealed and finished to complete the final product.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various changes, modifications and equivalents. Accordingly, the above description should not be construed as limiting the scope of the present invention defined by the limits of the following claims.

1: pillar transformer 10: enclosure
11: lid 20: high pressure bushing
21: apron 22: insulated housing
23: Connector 23c: Screw shaft
24: clamp 24a: clamp body part
24b: Cable connection portion 24c:
24d: cable receiving groove 24e: conductor connecting groove
24f: notch groove 25, 28: packing member
26: Enclosed 27: Cable
30: Low pressure bushing

Claims (4)

The connecting member is provided on the lid 11 of the pneumatic transformer 1 and applies a high-voltage power supplied from the outside by a winding. The connecting member includes a cylindrical body 21 having a hollow portion 21a formed therein, a columnar transformer The connector 23 is fixed to the inside of the hollow portion 21a of the cap 21 so as to be electrically connected to the inside of the connector 23 and connected to the connector 23, And a clamp (24) fixedly mounted on an upper end surface of the pipe (21) so as to be connected to the pipe (21), the method comprising the steps of:
The cable 27 is cut to a predetermined length so that one end of the cable 27 is inserted into the cable connection portion 24b of the clamp 24 and is then fixed by compression. And the screw shaft 23c of the connector 23 is prepared to be assembled so as to protrude from the upper end face of the auxiliary pipe 21. The clamp 24 is screwed on the screw shaft 23c and assembled, An adhesive is applied to the outer circumferential surface of the cap 21 and the clamp 24 and an insulating housing 22 made of a polymer material is injected onto the outer circumferential surface of the cap 21 and the clamp 24 by using an injection machine Shaped bushing for a pneumatic transformer.
The method according to claim 1,
The clamp 24 used for integrally connecting the cable 27 has a clamp body 24a formed with a screw hole 24c in the downward direction and a cable 24 protruded upward from the clamp body 24a, The cable connecting portion 24b includes a cable receiving groove 24d for accommodating the cover 27a of the cable 27 into the cable connecting portion 24b and a cable connecting portion 24b for connecting the cable 27, A structure in which a conductor coupling groove 24e having a diameter relatively narrower than that of the receiving groove 24d and capable of fitting the portion of the conductor 27b with the covering body 27a of the cable 27 peeled off is formed Shaped bushing for a pneumatic transformer.
3. The method according to claim 1 or 2,
The packing member 25 capable of preventing leakage can be inserted into the screw shaft 23c and mounted on the upper surface of the aerator 21 before the clamp 24 is fixed to the screw shaft 23c. (Method for manufacturing integral high voltage bushing for cable transformer.
The method according to claim 1,
After completing the high pressure bushing 20 by injection molding the insulation housing 22 made of a polymer material on the outer circumferential surface of the afore-mentioned cap 21 and the clamp 24, the end portion of the cable 27 and the injection portion of the clamp 24 are sealed And then finishing the high-voltage bushing.

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