JPH11121259A - Current transformer and unit thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current transformer with reliability and high non- defective ratio. SOLUTION: A unit for a current transformer includes a toroidal coil 3 made up of a toroidal core with a turned winding, an annular coil storing part, and a case with a plurality of pin terminals 2 and a terminal fixing part 11 for fixing the pin terminals 2. Then, the pin terminal 2 has projected parts 21 and 22 from both ends of the terminal fixing part 11, and the terminal of the winding of the toroidal coil 3 is connected to the projected part 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current transformer, and more particularly to a unit for a board-mounted zero-phase current transformer (current transformer) and a current transformer suitable for use as a leakage detector.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional current transformer unit. FIG. 3A is an external perspective view of a current transformer unit, and FIG.
(B) is sectional drawing (before resin injection | pouring) of the unit for current transformers.

As shown in FIG. 3, in a conventional current transformer unit, a toroidal coil 3 formed by uniformly winding a winding around the entire circumference of a toroidal core having a high initial permeability is provided with a case having pin terminals 32. 31, the winding terminal portion is connected to one end of the pin terminal 32 [two-dot chain line portion in FIG. 3 (b)] (bent solder), and the pin terminal 32 is bent in the direction of arrow 20 [FIG. (B) Solid line portion] The case 31 was filled with mold resin after being formed into an inverted L shape [FIG.
(A)]. Then, the pin terminal 32 of the current transformer unit is inserted into the mounting board, and a cable is passed through the hole 13 of the case 31 as a primary coil to complete the current transformer.

[0004]

Since a single copper wire is used for the pin terminal of the current transformer, the heat capacity of the pin terminal is larger than that of the winding terminal. Therefore, the joint between the pin terminal and the winding end is hardly heated, and there is a problem in solderability in connecting the winding end of a thin winding material with solder.

Further, since the soldered pin terminal is bent, the wire at the end of the winding is elongated and thinned, and the stress due to shrinkage during curing of the mold resin is applied to the wire at the end of the winding. The terminal is easily disconnected. For this reason, a defect such as a contact failure between the winding terminal and the pin terminal or a disconnection failure at the winding terminal may occur. It has been difficult to identify these defective portions because there is a false contact failure and the connection portions are covered with the mold resin. In addition, there remains a problem in improving the reliability and non-defective rate of the current transformer unit.

Accordingly, an object of the present invention is to provide a current transformer having high reliability and a high yield rate.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to a toroidal coil having a toroidal core wound thereon, a donut-shaped coil housing made of an insulating material for housing the toroidal coil, a plurality of pin terminals, and the pin terminal. And a case having a terminal fixing portion for fixing the pin terminal, wherein both ends of the pin terminal protrude from both end surfaces of the terminal fixing portion to form protruding portions, and a winding terminal portion of the toroidal coil is connected to one of the protruding portions. And a current transformer using the same.

According to the present invention, in order to solve the above-mentioned problems, a winding terminal is connected to a pin terminal, and without bending the pin terminal, a molding resin is injected into a case to complete a current transformer unit. is there. That is, the junction for the pin terminal and the winding end is exposed from the mold resin to complete the current transformer unit.

In the conventional current transformer unit, the joint between the pin terminal and the winding terminal is accommodated in the mold resin. In the present invention, the joint is visually inspected by exposing it from the mold resin. Since confirmation is possible, disconnection failure and contact failure can be easily found and repaired. Further, since there is no need to bend the pin terminals, disconnection defects can be reduced, so that the reliability and the yield rate can be improved.

[0010]

FIG. 1 is a perspective view showing the appearance of a current transformer unit according to the present invention (before molding resin is injected). Also,
FIG. 2 shows a case used for the current transformer unit of the present invention. FIG. 2A is an external perspective view of the case, and FIG. 2B is a side view of the case.

[0011] Toroidal cores are formed by laminating thin sheets made of permalloy C, and a magnet wire is wound around the toroidal core to obtain a toroidal coil 3 (Fig. 1).

As shown in FIG. 2, the case 1 having a donut-shaped coil housing portion 12 for housing the toroidal coil 2, a plurality of pin terminals 2, and a terminal fixing portion 11 for fixing the pin terminals 2 is insulated. The material is obtained by injection molding. Both ends of the pin terminal 2 protrude from both end surfaces of the terminal fixing portion 11 to form protrusions 21 and 22.

As shown in FIG. 1, the current transformer unit of the present invention houses the toroidal coil 3 in a coil housing (not shown) of the case 1 and a winding terminal of the toroidal coil 3. Was connected to one of the protruding portions 22, and the molding resin was further injected into the coil accommodating portion.

The projecting portion 21 of the current transformer unit of the present invention is inserted into the mounting board, and the hole 1 of the donut-shaped coil housing portion is inserted.
The current transformer is completed by passing the cable serving as the primary coil through 3.

[0015]

EXAMPLE A toroidal core was formed by laminating five donut-shaped permalloy C plates having an outer diameter of 13.6 mm, an inner diameter of 10.6 mm, and a thickness of 0.35 mm. A magnet wire having a nominal diameter of 0.1 mm was wound 500 turns to obtain a toroidal coil. Also, a hard copper wire with an outer diameter of 0.8 mm is 14 m long.
m, so as to protrude 3 mm from the terminal fixing portion to form a protruding portion 22 (FIG. 2) (length of the protruding portion 21 is 4 mm), and the inner diameter of the coil housing portion is 8.5.
mm was obtained. Then, the toroidal coil 3 was housed in the case 1, the terminal of the coil was connected to the pin terminal, and a mold resin was injected into the coil housing and cured to obtain a current transformer unit of the present invention.

In the current transformer using the current transformer unit of the present embodiment, no disconnection failure or contact failure occurred.

[0017]

According to the present invention, a current transformer having high reliability and a high yield rate can be obtained.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a current transformer unit of the present invention (before mold resin injection).

FIG. 2 is an explanatory view of a case used for a current transformer unit of the present invention. FIG. 2A is an external perspective view of a case, and FIG. 2B is a side view of the case.

FIG. 3 is an explanatory view of a conventional current transformer unit. FIG. 3 (a)
FIG. 3 is an external perspective view of the current transformer unit, and FIG. 3B is a cross-sectional view of the current transformer unit (before resin injection).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 (Case of the present invention) 11 Terminal fixing part (of the present invention) 12 Coil accommodating part (of the present invention) 13 Hole (of the coil accommodating part) 2 Pin terminal (of the present invention) 21, 22 (pin terminal of the present invention) ) Projection 3 Toroidal coil 31 (Conventional) case 32 (Conventional) pin terminal 20 Arrow

Claims (2)

[Claims] 1. A toroidal coil in which a winding is applied to a toroidal core, a donut-shaped coil storage portion made of an insulating material and storing the toroidal coil, a plurality of pin terminals, and a terminal fixing portion fixing the pin terminals. Wherein the two ends of the pin terminal protrude from both end surfaces of the terminal fixing portion to form a projecting portion, and a winding terminal portion of the toroidal coil is connected to one of the projecting portions. Current transformer unit. 2. A current transformer using the current transformer unit according to claim 1.