JPH0583163B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a split zero-phase current transformer, and is characterized in that it facilitates assembly and positioning of a secondary coil during assembly.

Prior Art A zero-sequence current transformer has an apparent zero-sequence current due to non-uniform positions between the primary conductor passing through the core and the core, or non-uniform distribution of the secondary coil wound around the core. It is known that a residual current appears, and especially in the case of a split core, the magnetic resistance of the joint is larger than that of other parts, and the residual current also increases. Therefore, in general, magnetic shields are provided on the inner periphery, outer periphery, and both side surfaces of the iron core to reduce the residual current. Conventionally, the stacking of iron cores, winding of secondary coils, attachment of magnetic shields, etc. of this split type zero-phase current transformer are performed as shown in FIG. FIG. 5 is a perspective view for explaining the assembly of one core of a split type zero-phase current transformer, and 50 indicates a semicircular core with an arbitrary width, and this core 50 is made of permalloy or silicon steel plate. It is formed by stacking thin plates such as When stacking, the sheets are alternately shifted one by one as shown in the drawings, and a concave-convex engaging portion is formed at the joint portions 50a at both ends. 5
A spacer 1 is provided at any location (three locations in the figure) on the iron core 50, and consists of a U-shaped member 51a and a stopper member 51b that closes the open end of the U-shaped member 51a. The thin plates are stacked and inserted, and the stopper member 51b is screwed to the U-shaped member 51a to fix them together. In addition, the inner and outer circumferential surfaces of the spacer 51 and the lower outer surface of FIG.
A screw hole for attaching a shield is provided on the upper surface of 1b. Reference numerals 52 and 53 denote an inner shield plate and an outer shield plate, which are arranged on the inner circumferential side and the outer circumferential side of the iron core 50, respectively, and are screwed to each spacer 51. 54 and 55 are side shield plates.
Similarly, spacers 51 are arranged at the top and bottom of the figure.
is screwed to. Also, side shield plates 54, 5
5 is fixed by providing a convex portion on the member 51a and providing a concave portion on the shield plate 55 that engages with the convex portion, as shown in FIG. 5B. When assembling, the iron core 50 made of stacked thin plates is fixed with screws using spacers 51, and after winding a coil between the spacers, the inner shield plate 52, side shield plates 54, 55, and outer shield plate 53 are attached. They are fixed to the spacer 51 with screws and integrated, and this is housed in a synthetic resin case to form a split core block A. Furthermore, the same split core block B is made and joined together as shown in FIG. The portions 50a are engaged to form a split type zero-phase current transformation.

Problems to be Solved by the Invention The above-mentioned problems require a technique to create irregularities of the same depth in the joint portion 50a by alternately sliding the thin plates one by one when making the iron core 50, and the spacer 51 and the shield plate 52 ~55 is fixed using a large number of screws, so it takes time to drill the screw holes and tighten the screws, and the position of the secondary coil relies on the operator's intuition, making it difficult to accurately position it. Therefore, the residual current characteristics become non-uniform, which poses a quality control problem.

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide a zero-phase current transformer of this type that is easy to assemble and allows accurate positioning of the secondary coil.

Means for Solving the Problem An iron core having a secondary coil and shielded at least on both sides with side shield plates is inserted into a groove of a case having a semicircular bottomed groove, and a cover is placed on the open side of the groove. In a zero-phase current transformer in which two iron core blocks are attached to each other to form an iron core block, and both ends of the iron core are engaged with each other, a guide pin is implanted in the bottomed groove, and a guide pin is installed in the bottomed groove, and An insertion hole is provided through which the guide pin is inserted.

Further, an engaging protrusion is provided on the coil bobbin around which the secondary coil is wound, and two engagement protrusions are provided on the side shield plate.
Next, a positioning hole into which the engaging protrusion is inserted is provided at a position where the appropriate position of the coil is determined.

Function: Insert the guide pin into the insertion hole of the side shield plate, the iron core, and the side shield plate in this order, and fix the iron core and side shield plate in the groove. This eliminates the need to attach the side shield plate with screws.

In addition, there are two
Next, insert the engaging protrusion of the coil. This fixes the secondary coil in place.

Embodiment FIG. 1 shows an exploded view of one split core block A of a split zero-phase current transformer for explaining an embodiment of the present invention. Semicircular thin plate 1' of permalloy or silicon steel plate, etc.
They are stacked and integrally formed by fixing means such as screws or caulking. Holes a and b are bored at both ends of the semicircular thin plate 1' at a distance l ₁ and a distance l ₂ from the end, respectively. These distances l ₁
The relationship between l 1 and l ₂ is l ₁ > l ₂ , and the difference h is the depth of the groove at the joint (Fig. 2B). In this way, hole a,
An arbitrary number of holes are alternately inserted into the thin plate 1' provided with holes a, b,
Lay them on top of each other so that they are a, b, etc., insert screws (or caulking rods) into each hole a and b, and tighten them together. A secondary coil 2 is wound around a bobbin and attached to the iron core 1. Further, the thin plate 1' forming the iron core 1 is provided with insertion holes c and d into which a guide pin 5, which will be described later, is inserted. Reference numeral 3 denotes a case made of synthetic resin, in which a semicircular bottomed groove 4 into which the iron core 1 is inserted is formed, and two guide pins 5 are implanted at an arbitrary interval in the bottom of the groove 4 . The case 3 also includes a semicircular window 6 through which the primary conductor passes, a plurality of screw holes 7 for fixing the cover, and guide members 8 and 9 for interlocking with the other split core block B. has. The secondary coil 2 is formed by winding an electric wire around a bobbin 11, as shown in FIG. 3, and the bobbin 11 is made of an insulating material such as synthetic resin.
A body part 13 having a rectangular cross section and having an insertion hole 12 through which the iron core 1 is inserted, a square plate collar member 14 provided at both ends of this body part 13, and both collar members 14.
Engagement protrusions 15 protruding from the upper and lower sides (in FIG. 3) of the
It is composed of 16. Reference numeral 20 denotes a side shield plate made of a magnetic material, and one or more side shield plates (two in the illustrated embodiment) are disposed on both the left and right sides of the iron core 1. This side shield plate 20 includes, as shown in FIG.
Positioning holes 15a and 16a into which the engaging protrusions 15 and 16 of the bobbin are inserted, and an insertion hole 21 into which the guide pin 5 of the case 1 is inserted are bored in the area where the secondary coil 2 is to be installed. ing. 22
is an inner circumferential shield plate formed in a semicircular shape, and an insulating film 24 is adhered to the outer circumferential surface of the plate using a double-sided adhesive tape 23 or the like and attached to the inner circumferential surface of the groove 4 of the case 3, and both ends thereof are attached to the locking portions 1a. to be locked. Reference numeral 25 denotes an outer circumferential shield plate, which is attached to the outer circumferential surface of the groove 4, and its both ends are engaged with the outer circumferential locking portions 1b. 26 is the cover of case 3, which has iron core 1 and side shield plate 2.
After accommodating the shield plates 22 and 25 on the inner and outer circumferential surfaces, the cover 26 is covered and they are attached together with screws or the like to form a split core block A (or B).

Next, to explain the assembly order, first, as shown in FIG. 2A, one of the semicircular thin plates 1' made of magnetic material
A hole a is provided on one end at a distance of l ₁ from the end, a hole b is provided on the other end at a distance of l ₂ from the end, and an insertion hole c is provided at a distance of l 2 from the end on the other end. A thin plate 1' with holes d is punched out, and as shown in Fig. 2A, an arbitrary number of sheets are stacked by turning them over alternately so that holes a, b, a, b, etc. are formed, and bolts are inserted into these holes. The iron core 1 is formed by tightening it with a nut, and the secondary coil 2 wound around the bobbin 11 is attached to the iron core 1.
Insert individually. Next, a side shield plate 20 is prepared in which an appropriate position for the coil 10 is determined in advance, positioning holes 15a and 16a are provided in the portion corresponding to the position, and an insertion hole 21 for the guide pin 5 is provided. Then, attach the side shield plate 2 to the guide pin 5.
0, the iron core 1 provided with the secondary coil 2, and the side shield plate 20 are inserted into the groove 4 by inserting them through the insertion holes c, d and 21, and then the inner circumferential shield plate is inserted. 22 and the outer peripheral shield plate 25 are inserted along the inner and outer peripheral surfaces of the groove 4, and the cover 26 is attached to form split iron core blocks A and B.

In the embodiment shown in FIG. 1, the guide pin 5 is provided only on the bottom side of the bottomed groove 4, but as shown in FIG. 4, the length of the guide pin 5 on the case 3 side is shortened. A short guide pin 5' may also be provided on the cover 26 side at a position opposite to this.

Further, in the same embodiment, the positioning of the secondary coil 2 is performed by the side shield plate fixed by the guide pin 5, but the fixing of this shield plate is not limited to the guide pin. It goes without saying that this can also be applied to the case where it is fixed.

Effects of the Invention As described above, in the present invention, a guide pin is installed at the bottom of the bottomed groove in the case, and an insertion hole through which the guide pin is inserted is provided in the side shield plate and the iron core, and the guide pin is inserted into the groove. Since the side shield plate, iron core, and side shield plate are housed in this order using the guide pin as a guide, there is no need for a conventional spacer, and therefore there is no need to process screws on the spacer or screw the side shield plate. As a result, manufacturing man-hours are drastically reduced.

In addition, the appropriate position of the secondary coil (residual current increases or decreases depending on the installation position of the secondary coil, but the position with the least residual current) is placed on the side shield plate in advance.
Since a positioning hole is provided in the bobbin of the secondary coil, and an engaging protrusion that is inserted into this hole is provided on the bobbin of the secondary coil, it is necessary to insert the engaging protrusion of the secondary coil into the positioning hole of the side shield plate. The next coil will be installed in the proper position, so there will be less residual current.
Moreover, this type of zero-phase current transformer with uniform characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a split core block according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of the core assembly of the present invention, FIG. 3 is a perspective view of a coil bobbin of the present invention, and FIG. 4 is a perspective view of a split core block of the present invention. FIG. 5 is an exploded perspective view of a conventional split iron core block, and FIG. 6 is a front view of a split type zero-phase current transformer. 1... Iron core, 2... Secondary coil, 3... Case, 4... Bottomed groove, 5... Guide pin, 11...
...Coil bobbin, c, d, 21...Insertion hole, 1
5, 16... Engaging protrusion, 15a, 16a... Positioning hole, 20... Side shield plate, 22... Inner circumference shield plate, 25... Outer circumference shield plate, 26...
cover.

Claims (1)

[Claims] 1. An iron core having a secondary coil and having at least both sides shielded by side shield plates is inserted into a groove of a case having a semicircular bottomed groove, and a cover is placed on the open side of the groove. In a zero-phase current transformer in which two iron core blocks are attached to each other to form an iron core block, and both ends of the iron core are engaged with each other, a guide pin is implanted in the bottomed groove, and a guide pin is installed in the bottomed groove, and A through hole is provided through which a guide pin is inserted, and the side shield plate, the iron core, and the side shield plate are inserted into the guide pin in this order, and the side shield plate and the iron core are fixed in the groove. Split type zero-phase current transformer. 2 Insert an iron core having a secondary coil and shielding at least both sides with side shield plates into a groove of a case having a semicircular bottomed groove, and attach a cover to the open side of the groove to form an iron core block. In a zero-phase current transformer in which two of these iron core blocks are meshed with each other at both ends of the iron cores, an engaging protrusion is provided on the side shield plate side of the coil bobbin around which the secondary coil is wound, and the side shield plate A positioning hole into which an engaging protrusion is inserted is provided at a position where the appropriate position of the secondary coil is determined, and the secondary coil is positioned by inserting the engaging protrusion into the positioning hole. Split type zero phase current transformer.