JPH0773797A - Terminal device for earth leakage breaker - Google Patents

Abstract

PURPOSE:To prevent the generation of looseness of the fastening of a neutral wire at a low cost in an earth leakage breaker with a function for protecting a neutral wire from phase interruption for single-phase three-wire. CONSTITUTION:Two block terminals 5 having one screw structure (provided with one terminal screw 5b) are provided in a terminal unit, to which a neutral wire 8 is connected, in parallel with each other. The wire 8 is fastened to a terminal board 4 at two positions by the terminal screw 5b of each block terminal 5 to eliminate the generation of danger of phase interruption of a neutral wire due to the looseness of fastening, and an investment in a new mold for manufacturing a block terminal having two-screw structure is eliminated to reduce the cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal device for an earth leakage breaker with a neutral line open phase protection for single-phase three-wire.

[0002]

2. Description of the Related Art Voltages of 100 V and 200 V can be used in a single-phase three-wire circuit. However, if the neutral wire is out of phase due to imperfect tightening of terminal screws or the like, overvoltage will be applied to 100 V equipment under load. Is applied, which may lead to insulation deterioration or failure of electrical equipment. For example, FIG. 3 is a connection diagram in which 100 W devices 2 and 3 of 40 W and 200 W are connected to a single-phase three-wire circuit via an earth leakage breaker 1 with a neutral wire open phase protection. Phase), the voltage that was balanced between the load devices becomes unbalanced, and the 40W device 2 has 16
7V is applied, and a voltage of 33V is applied to the 200W device 3. When the zero-phase current transformer 1a detects the occurrence of an unbalanced current between the phases due to a ground fault, the earth leakage breaker 1 operates to open the circuit by driving the contact 1c with the output of the trip circuit 1b.

FIG. 2 is a longitudinal sectional view of a main part showing a neutral wire connecting terminal portion of a conventional earth leakage breaker with a neutral wire open phase protection. The block terminal 5 is inserted into the terminal plate 4 integrated with the fixed contactor,
These are attached to the case 6 of the earth leakage breaker 1 and the cover 7
Is held by. The electric wire 8 connected to the terminal board 4 is guided along the guide piece 9 into the rectangular block 5a of the block terminal 5.
It is inserted in and is tightened as shown by the terminal screw 5b.

[0004]

The block terminal shown in FIG. 2 has one terminal screw (one-screw structure). However, one terminal screw does not sufficiently tighten the electric wire, and thus the above-mentioned problem occurs. There is a lot of room for failure of electrical equipment due to phase loss. Therefore, if a terminal block (two-screw structure) is provided with two terminal screws in one block, the tightening will be reliable. However, in order to obtain the two-screw structure, it is necessary to invest in a mold for molding a new block, which is problematic in terms of cost. An object of the present invention is to provide a terminal device of an earth leakage breaker capable of securely tightening an electric wire of a neutral wire without a mold investment.

[0005]

The present invention achieves the above object by arranging two block terminals having a one-screw structure side by side in a terminal portion for connecting a neutral wire.

[0006]

[Function] For the neutral wire, the block terminals having a single screw structure are arranged side by side in a row, so that the wire can be securely tightened while using the conventional block terminals, and the open phase of the neutral wire can be effectively prevented. can do. Note that the number of block terminals for other phases may be one.

[0007]

1 is a longitudinal sectional view of an essential part showing a neutral wire connecting terminal portion of an earth leakage breaker with a neutral wire open phase protection according to an embodiment of the present invention. The same reference numerals are used for the parts corresponding to those of the conventional example. In the figure, 1 is attached to the terminal portion of the case 6.
Two block terminals 5 having a screw structure are provided side by side in the front and rear, and are held by a cover 7 together with the terminal plates 4 inserted therein. The electric wire 8 inserted across the two blocks 5a is fastened in two places by the respective terminal screws 5b.

[0008]

According to the present invention, since the block terminals having the one-screw structure are arranged side by side in the terminal portion for connecting the neutral wire, the electric wire of the neutral wire is tightened with the two terminal screws. Since the connection with the terminal board is secure and the conventional block terminal can be used as it is, there is no need for mold investment when newly manufacturing a block terminal with a 2-screw structure, and reliable neutral wire open phase protection. It can be realized at low cost.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part showing a neutral wire connecting terminal portion of an earth leakage breaker with a neutral wire open phase protection according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part showing a neutral wire connecting terminal portion of a conventional earth leakage circuit breaker with an open phase protection.

FIG. 3 is a connection diagram when a load is connected to a single-phase three-wire circuit via an earth leakage circuit breaker with a neutral line open-phase protection.

[Explanation of symbols]

 4 Terminal plate 5 Block terminal 5b Terminal screw 6 Case 7 Cover 8 Electric wire

Claims (1)

[Claims] 1. A ground fault circuit breaker with a neutral wire open-phase protection, wherein one terminal block connecting a neutral wire has two screw block terminals.
A terminal device for an earth leakage breaker, which is arranged in series.