JPH06260355A - Simple current transformer - Google Patents

Abstract

PURPOSE:To provide a current transformer of a simple structure at low manufacturing cost that has a sufficient weather resistance. CONSTITUTION:A hot zinc dipping is directly performed with an electromagnetic steel plates 1 and 2, to be used as an iron core, and a coil is wound around the iron core, and then only a coil part 3 is mold-processed. The hot zinc dipping should be air cooling type hot zinc dipping or low temperature type hot zinc dipping, for preventing degradation in the characteristic of an electromagnetic steel plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple type current transformer mounted on a power transmission line, a transformer or the like and used outdoors.

[0002]

2. Description of the Related Art Conventionally, a current transformer (CT) used outdoors
For, in order to improve the weather resistance, coiled electromagnetic steel sheet, rubber mold, epoxy mold,
It was usual to apply a silicone mold or the like. In particular, in the case of a split type current transformer in which the iron core is split to facilitate mounting, measures such as attaching an O-ring to the split part in addition to the above-described molding treatment to prevent water from entering from the split part. However, there is a problem that the structure becomes complicated and the cost becomes high.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and has a simple structure, a low manufacturing cost, and a simple current transformer having sufficient weather resistance for outdoor use. Has been completed in order to provide.

[0004]

DISCLOSURE OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, a coil is wound on an iron core made by directly galvanizing an electromagnetic steel sheet, and only the coil portion is molded. The gist is a simple type current transformer characterized by. The hot-dip galvanizing is preferably air-cooling hot-dip galvanizing or low-temperature hot-dip galvanizing, and the iron core is preferably a split type to facilitate mounting.

[0005]

In the simple current transformer of the present invention, the magnetic steel sheet is directly galvanized to form the iron core. However, hot dip galvanizing can form a film having excellent weather resistance. By molding only the coil portion wound on the iron core, it can be used outdoors for a long period of time. As shown in the graph of FIG. 1, the galvanized steel sheet has a slightly lower current detection characteristic than that before plating, but air-cooled hot dip galvanization that cools slowly in the air after plating and plating temperature If low-temperature hot-dip galvanizing at 370 to 400 ° C is adopted, the deterioration of characteristics can be suppressed more than in the case of applying ordinary water-cooled hot-dip galvanizing, and a simple current transformer with no problems in practical use. Can be

[0006]

The present invention will be described below in more detail with reference to the illustrated embodiments. [Embodiment 1] As shown in FIG. 2, two electromagnetic steel plates 1 and 2 having a thickness of 4 mm are press-formed into a U-shape and 800-1050.
Annealed at ℃, it was immersed in a molten zinc bath at 450-480 ℃.
The two magnetic steel sheets pulled out of the bath were slowly cooled in the air. The diameter of the electromagnetic steel plate 1 on one side is 0.26 at the center.
An enamel wire of mm was wound 2000 times to form the coil portion 3, and only the coil portion 3 was rubber-molded. afterwards,
The two electromagnetic steel plates 1 and 2 were adhered to each other with bolts or the like to form a simple rectangular current transformer.

When a current of 10 A was passed through the inside of the iron core of this simple type current transformer and the voltage generated in the load resistance connected to both ends of the coil part 3 was measured, the result shown in the graph of FIG. 4 was obtained. was gotten. It is to be noted that, although it is a simple type current transformer having the same shape, a curve is shown when an electromagnetic steel sheet not plated is used.

[Embodiment 2] As shown in FIG. 3, the thickness is 4 mm.
Of the two electromagnetic steel plates 4 and 5 are press-formed into a linear shape on one side and a C shape on the other side, and then annealed at 800 to 1050 ° C.
It was immersed in a molten zinc bath at 480 ° C. The two electrical steel sheets pulled out of the bath were slowly trained in the air. A coil portion 6 was formed by winding an enameled wire having a diameter of 0.26 mm 2000 times around the central portion of a linear electromagnetic steel plate 4, and only the coil portion 6 was rubber-molded. After that, the two electromagnetic steel plates 4 and 5 were brought into close contact with each other by bolts or the like to form a simple rectangular current transformer.

Similar to the first embodiment, a current of 10 A was passed through the inside of the iron core of this simple current transformer, and the voltage generated in the load resistance connected to both ends of the coil 6 was measured. The results shown as in the graph of 4 were obtained. It is a measurement curve for a simple type current transformer of the same shape using an electromagnetic steel sheet that is not plated.

FIG. 5 shows a graph of the output current with respect to the through current of the air-cooled hot dip galvanized sample according to the first embodiment. From this, it is understood that the characteristics as the current transformer are satisfied.

[0011]

As described above, the simplified current transformer of the present invention is one in which a coil is wound on an iron core made by directly galvanizing an electromagnetic steel sheet and only the coil portion is molded. Therefore, the structure is simple and can be manufactured at a low cost, as compared with a conventional electromagnetic steel sheet which is entirely rubber-molded, epoxy-molded, or silicon-molded. In addition, even when the split type is used, there is an advantage that no special waterproofing measure is required for the split part. Further, by adopting air-cooled hot-dip galvanizing or low-temperature hot-dip galvanizing, it is possible to suppress the characteristic deterioration of the electrical steel sheet to such an extent that there is no practical problem. Therefore, the present invention has a great contribution to the industry as a simple type current transformer that solves the conventional problems.

[Brief description of drawings]

FIG. 1 is a graph showing changes in load characteristics due to differences in plating methods for magnetic steel sheets.

FIG. 2 is a front view showing a first embodiment.

FIG. 3 is a front view showing a second embodiment.

FIG. 4 is a graph showing load characteristics of the simplified current transformer of the embodiment.

FIG. 5 is a graph of output current with respect to through current of the simple current transformer of the first embodiment.

[Explanation of symbols]

 1 electromagnetic steel plate 2 electromagnetic steel plate 3 coil part 4 electromagnetic steel plate 5 electromagnetic steel plate 6 coil part

Claims (3)

[Claims] 1. A simple current transformer characterized in that a coil is wound on an iron core formed by directly subjecting an electromagnetic steel sheet to hot dip galvanizing, and only the coil portion is subjected to a mold treatment. 2. The simplified current transformer according to claim 1, wherein the hot dip galvanizing is air cooling hot dip galvanizing or low temperature hot dip galvanizing. 3. The simplified current transformer according to claim 1, wherein the iron core is of a split type.