JP2606365B2 - Current transformer or zero-phase current transformer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a current transformer or a zero-phase current transformer used for measurement in electrical equipment or the like of a distribution line, and more specifically, to a single-phase current transformer. A current transformer body embedded in a resin mold, and a secondary coil at a terminal of a secondary coil of the current transformer body. The present invention relates to an improvement of such a current transformer having terminals.

[Conventional technology]

Current transformers and zero-phase current transformers are made by placing an annular special steel plate core shaped in a way that is convenient for penetrating conductors into an insulating shell, Is a main body formed by winding a secondary coil so as to be orthogonal and further pressing and winding with a tape, and using a lead-out portion of the terminal of the secondary coil out of the main body or a lead wire connected to the terminal. And connected to the secondary terminal.

Such a converter or a zero-phase current transformer penetrates the cable conductor itself of the distribution line or the primary conductor directly or indirectly connected thereto, and induces a voltage to the secondary coil by the magnetic field of the conductor. And is used to measure the current flowing through it.

FIG. 7 shows the current transformer (CT),
As shown in the drawing, the terminal of the secondary coil in the main body of the ring-shaped current transformer main body 1 in which a single-phase primary conductor A connected to one phase of a single-phase or multi-phase multi-wire line is arranged to penetrate. The terminals 4 and 5 were joined at the secondary terminals lt and ht by pulling out the terminals 2 and 3 directly or connecting the lead wires to the coil terminals.

FIG. 8 shows a zero-phase current transformer (ZCT). As shown, three primary-side conductors A and A of a three-phase three-wire system are shown.
Penetrate B or C, or penetrate two primary conductors in a single-phase two-wire system, three in a three-wire system, three in a three-phase system, and four in a four-wire system in three-phase AC, Used to measure zero-sequence current.

In the case of the zero-phase current transformer of this example, the above-mentioned current transformer (CT)
In the same manner as in the above, with respect to the ring-shaped current transformer main body 11, the terminals 12, 13 of the secondary coil in the main body are directly drawn out as shown in the drawing, or a lead wire is connected to the coil terminal. The terminals 14 and 15 were joined at the secondary terminals lt and ht thus configured.

[Problems to be solved by the invention]

In such current transformers (CT) and zero-phase current transformers (ZCT), when buried in a resin mold, the secondary coil extraction terminals 2, 3, 12, 13 derived from the current transformer bodies 1, 11 are provided. Alternatively, the terminals 4, 5, 14, 15 connected to the lead wires connected thereto are eccentric by the pressure at the time of resin molding, and the coil terminals 2, 3, 12,
13 could move and come into contact with the primary conductors A, B, and C.
Also, in some cases, the secondary coil extraction portion 2,
3, 12, 13 or the lead wire connected to it often breaks, and it was not possible to efficiently manufacture a product having stable performance.

The present invention has been made in view of the above-described conventional technology, and prevents eccentricity and disconnection of a secondary terminal embedded in a resin mold together with a current transformer main body, thereby facilitating manufacture and ensuring stable current transformer or zero-phase current transformer. The purpose is to provide a current transformer.

[Means and actions to solve the problem]

Means of the present invention made to achieve this object is as follows. In the current transformer, a pair of conductive rods having rigidity are fixed to an annular current transformer body embedded in a resin mold body. That is, the base ends are integrally fixed so as to be erected at intervals and connected to the secondary coil.

According to the above, when the current transformer main body is embedded in the resin mold material, the conductive rod acts as a rigid body supporting the main body by locking the tip of itself to the mold. Therefore, the current transformer main body can be accurately embedded in the molding material, and the conductive rod as a rigid body can be embedded in the molding while maintaining a predetermined position without yielding to the pressure of the molding material. In addition, since the base end of the conductive rod is connected to the secondary coil in the main body, it can be used as a lead to form a secondary terminal.

On the other hand, in the zero-phase current transformer, a pair of rigid conductive rods and a pair of rigid support rods are fixed to an elliptical annular zero-phase current transformer body embedded in a resin mold body. That is, the base end is integrally fixed so as to be erected at intervals, and the conductive rod is connected to a secondary coil.

According to the above, when the zero-phase current transformer main body is buried in the resin molding material, the conductive rod-like body and the support rod are locked at their ends by the molding die, so that the main body can be formed. Acts as a supporting rigid body, so that the zero-phase current transformer body can be accurately embedded in the molding material, and the conductive rods and the supporting rods as rigid bodies maintain a predetermined position without yielding to the pressure of the molding material. Then, it can be embedded in the mold body. In addition, since the base end of the conductive rod is connected to the secondary coil in the main body, it can be used as a lead to form a secondary terminal.

In a preferred embodiment of the rigid conductive rod and support rod, the distal end is provided with a screw hole into which a support bolt for molding is screwed, and a seat is integrally provided at a base end. It is applied to the side surface of the current transformer body and fixed to the current transformer body with tape.

〔Example〕

FIG. 1 shows a preferred embodiment of a current transformer (CT) according to the present invention.
Apply two conductive rods 6, 7 in the form of round rods having rigidity with a good conductive metal material such as copper, with the same length,
The base ends of the two conductive rods 6 and 7 are integrally fixed to the outer peripheral surface of the current transformer main body 1 so as to be erected in parallel at a predetermined interval from the outer peripheral surface thereof. The secondary coil terminals 2, 3 of the current transformer main body 1 are joined to the base end.

The two conductive rods 6, 7 have perforations 6a, 7a at their ends, and are used for screw connection of the terminals of the measurement lead wires. It is also used for screwing to molds.

FIG. 2 shows a preferred embodiment of a zero-phase current transformer (ZCT) according to the present invention.
In contrast to 11, two rod-shaped conductive rods 16 and 17 having rigidity made of a good conductive metal material such as copper and two support rods made of an appropriate metal rigid body or rigid plastic rigid body 18 and 18 are applied with the same length, and these two conductive rods 16 and 17 and the two support rods 18 and 18 are formed on the side peripheral surface of the zero-phase current transformer main body 11 in a rectangular shape. The base ends thereof are integrally fixed to the side peripheral surface so as to stand in parallel from the position corresponding to the corner point, and the secondary ends of the zero-phase current transformer main body are formed at the base ends of the conductive rods 16 and 17. The coil terminals 12, 13 are joined together.

The two conductive rods 16, 17 and the two support rods 18,
At the end of 18, the screw holes 16a, 17a and 18a are drilled at the tip, and the screw holes 16a and 17a of the two conductive rods are used for screw connection of the measurement lead wire terminal, The screw holes 16a and 17a of the conductive rod and the screw holes 18a of the support rod can be used for screwing to a resin mold described later.

FIG. 3 shows the two conductive rods 6, 7 or 16,
Current transformer body 1 or zero-phase current transformer body 11 of support rod 17 and support rod 18
This shows an example of fixing to a bar,
A plate-shaped seat body 20 is integrated with the base end of the seat body 20 by welding or the like, and the seat body 20 is applied to the outer surfaces of the current transformer main bodies 1 and 11, and a tape 22 is wound around the current transformer main body 1 It is designed to be tightly bound to 11.

FIG. 4 shows two conductive rods 6, 7 or 16,
Current transformer body 1 or zero-phase current transformer body 11 of support rod 17 and support rod 18
In this embodiment, a plastic (insulating) spacer 21 having a dovetail-shaped locking groove opened on the upper side is used. Engage the seat body 20 integrated with the base end of the rod 6, 7 or 16-18, and apply the spacer 21 to the outer surface of the current transformer main body 1, 11;
The tape 22 is wrapped around the perimeter, and the seat body 20 is tightly fixed together with the spacer 21.

According to the present embodiment, even if the seat body 20 is made of metal, the seat body 20 is applied to the current transformer main bodies 1 and 11 via the spacers 21 made of plastic. In addition, when the rod, especially the support rod 18 is made of metal, it is useful for achieving electrical insulation from the current transformer bodies 1 and 11.

FIG. 5 shows an example of resin molding for the current transformer (CT) shown in FIG. 1. In a state where the phase conductor A is passed through the current transformer main body 1, a molding die ( B) Put it in (b), fit the tips of the conductive rods 6 and 7 into the concave groove on the inner surface of the mold (a), and penetrate from the bottom of the concave groove of the mold (a) By screwing a bolt (e) screwed into the screw hole from the outside into the screw hole of the conductive rods 6 and 7, the conductive rods 6 and 7 are fixed to the mold (a). Conductive rod body in which current transformer body 1 is made of a rigid body
In a state of being suspended and supported by 6, 7, it is arranged so as not to move to a predetermined position in the molds (a) and (b).

Reference numeral 100 denotes a resin molding material press-fitted into a mold, whereby the current transformer main body 1 is buried in a state where the primary conductor A is penetrated and integrated, and the current transformer main body 1 is also buried therewith. 7 is also embedded and integrated in the resin molding material 100.

Since the conductive rods 6 and 7 are rigid and locked to the mold (a) and are integrally fixed to the current transformer main body 1,
There is no eccentricity or movement due to the press-fitting of the resin mold material 100, and the current transformer main body 1 can also keep a fixed position.

The primary conductor A to be penetrated is, for example, a metal conductor such as a copper rod having sufficient rigidity so as not to be deformed by press-fitting of the resin molding material 100, and has a conductive rod-shaped body 6, the end of which is a secondary terminal. By bolting to the mold (b) in the same manner as in 7, it is possible to maintain a constant state penetrating the current transformer body 1. (This example is illustrated in FIG. 6, so please refer to FIG. 6.) FIG. 6 shows an example of resin molding of the zero-phase current transformer (ZCT) shown in FIG. With the three-phase three-wire primary conductors A, B, and C penetrated through the zero-phase current transformer main body 11, they are put into a mold (c) (d), and the conductive rods 16, A bolt (c) which fits the tips of the support rod 17 and the support rod 18 into a groove formed on the inner surface of the mold (c) and further externally passes through a screw hole penetrating from the bottom of the groove of the mold (c). Are screwed into the screw holes of the conductive rods 16 and 17 and the support rod 18, whereby the conductive rods 16 and 17 and the support rod 18
Is fixed to the mold (c), and the zero-phase current transformer main body 11 is suspended and supported by the conductive rods 16 and 17 and the support rods 18 made of a rigid body. It is arranged so as not to move to a predetermined position in d). For the primary conductors A, B, and C of each phase, as a rigid body of a metal conductor such as the same rod,
Bolts (f) which fit the ends into the grooves formed on the inner surface of the mold (d) and which are threaded from the outside into the screw holes penetrating from the bottom of the grooves of the mold (d) are connected to the primary conductor A, Each phase conductor A, B, C is fixed to the mold (d) by screwing it into the screw hole drilled at the end of B, C, so that the rigid primary conductor
A, B, and C continue to maintain the zero-phase current transformer 11 while penetrating the fixed position.

The resin molding material 100 press-fitted into the mold is press-fitted so as to fill the periphery of the zero-phase current transformer main body 11 and between the primary conductors A, B, and C, and between them, and the conductive rod 16 , 17 and the support rod 18 so as to fill the primary conductors A, B, and C, thereby completing a zero-phase current transformer.

In the case of the present embodiment, similarly to the embodiment of FIG.
The press-fitting of the resin molding material 100 prevents the zero-phase current transformer 11 from moving and the conductive rods 16, 17 and the support rod 18 from eccentricity and movement.

In the above embodiment, the example in which the penetrating primary conductor is penetrated and integrated into the current transformer main body by the mold body has been described. However, in the present invention, the current transformer main body and the conductive rod-shaped body (and When the support rod) is embedded and integrated into the resin mold body, the disposal rod is passed through the current transformer body,
In a finished state after the molding, it can be supplied as a product having a conductor through-hole formed in the current transformer main body.

The product contributes to measurement by being inserted into the cable of the distribution line.

[Effects of the Invention] As is clear from the above description, according to the current transformer or the zero-phase current transformer of the present invention, the eccentricity and disconnection of the secondary terminal embedded in the resin mold together with the current transformer main body are prevented. However, the intended purpose of providing a current transformer or a zero-phase current transformer that is easy to manufacture and has stable performance can be sufficiently achieved, and the rejection rate during manufacturing can be extremely reduced. Also can supply with advantageous products.

[Brief description of the drawings]

FIG. 1 is a perspective explanatory view showing one embodiment of a current transformer according to the present invention, FIG. 2 is a perspective explanatory view showing one embodiment of a zero-phase current transformer according to the present invention, and FIG. 4 (a) and 4 (a) are a sectional explanatory view and a planar explanatory view showing a fixing agent to a current transformer main body of a conductive rod or a support rod in the current transformer or the zero-phase current transformer. ) And (b) are cross-sectional and plan views showing another example of a structure for fixing a conductive rod or a support rod to a current transformer body in the current transformer or the zero-phase current transformer. FIG. 5 is a cross-sectional explanatory view showing an example of resin molding on the current transformer, and FIG. 6 is a cross-sectional explanatory view showing an example of resin molding on the zero-phase current transformer. FIG. 7 is a perspective explanatory view showing an example of a conventional current transformer, and FIG. 8 is a perspective explanatory view showing an example of a conventional zero-phase current transformer. In the figure, 1 is the current transformer body, 2, 3, 12, and 13 are secondary coil terminals, 1
1 is a zero-phase current transformer body, 6, 7, 16, and 17 are rigid conductive rods, 18 is a rigid support rod, 20 is a seat, 21 is a plastic spacer, and 22 is a binding rod. Tape, 6a, 7a, 16a, 17a
Is a screw hole, A, B and C are primary conductors, (A) (B) (C)
(D) is a mold, (e) and (f) are bolts, and 100 is a resin mold material.

Claims (3)

(57) [Claims] 1. A pair of rigid conductive rods are integrally fixed to an annular current transformer main body buried in a resin mold body so as to be erected at predetermined intervals. A current transformer, wherein the current transformer is connected to a secondary coil. 2. A pair of rigid conductive rods and a pair of rigid support rods are erected at predetermined intervals with respect to an elliptical annular zero-phase current transformer body embedded in a resin mold body. Characterized in that the base end is integrally fixed as described above and the conductive rod is connected to a secondary coil. 3. The rigid conductive rod-like body and the supporting rod are:
It has a screw hole for screwing a bolt at the tip, and has a seat body integrally at the base end, and the seat body is applied to the side surface of the current transformer main body and is fixed to the current transformer main body by tape and fixed. Item 7. The current transformer or the zero-phase current transformer according to (1) or (2).