JPH04368746A - Circuit breaker - Google Patents

Abstract

PURPOSE:To bring a connection terminal and a contactor into surface contact with each other uniformly and prevent defective contact in the contact position even when the contacting end surface of the connection terminal on the breaker side or on the current limiting apparatus side to connect the breaker and a current limiting apparatus and the contacting end surface of the contactor are not parallel or in different positions, in a circuit breaker composed of combination of the breaker and the current limiting apparatus. CONSTITUTION:A flexible part 23 such as a shant, etc., having conductive properties is provided between a connection terminal 20 and contactors 5, 14 in the breaker side or a current limiting side, so that the end face of the connection terminal and the end face of the contactor are brought into surface contact uniformly with each other at the time of combining the breaker and the current limiting apparatus.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a current-limiting type circuit breaker in which a current limiter having a current-limiting function is connected to the circuit breaker.

0002

2. Description of the Related Art There is a type of circuit breaker in which a current limiter having a current limiting function is polymerized into the circuit breaker. The conventional structure of this circuit breaker will be explained based on FIGS. 6 to 9. The circuit breaker 1 consists of a circuit breaker 2 and a current limiter 3. Circuit breaker 2
is surrounded by an insulating casing 4, which includes a fixed contact 5 having a fixed contact 6, and a movable contact 9 facing the fixed contact 6.
A movable contactor 8 having a movable contactor 8, a contact arm 10 for operating the movable contactor 8, a shaft 11 for rotatably holding the contact arm 10, and a housing 4 for the contact arm 10.
An operating handle 7 and the like that are operated from the outside are provided. 12 is a terminal for connecting an external conductor that communicates with the movable contactor 8. The current limiter 3 is surrounded by an insulating case 13, and this insulating case 1
The upper surface of the circuit breaker 3 is in close contact with the bottom surface of the insulating casing 4 of the circuit breaker 2. Fixed contacts 15a and 1 are provided inside the insulating casing 13, respectively.
5b, and the contact 1
Repulsion movable contacts 16a, 16b having movable contacts 17a, 17b opposite to 5a, 15b are provided. 1
Reference numerals 8a and 18b are contact pressure springs that are provided inside the insulating casing 13 and urge the movable contacts 16a and 16b upward. Normally, the movable contacts 17a, 17b are in contact with the fixed contacts 15a, 15b due to the urging force of the contact pressure springs 18a, 18b. 19 is a terminal for connecting an external conductor connected to the fixed contact 14b. The circuit breaker 2 and the current limiter 3 are connected via a connecting terminal 20. In this example, the connection terminal 20 has a substantially cylindrical shape with a screw hole formed in the center, and its lower end surface is fixed to the upper surface of the fixed contact 14a. The upper part of this connection terminal 20 projects from a hole 21 formed in the insulating casing 13, as shown in FIG. The bottom surface of the fixed contact 5 on the circuit breaker 2 side is in contact with the upper surface of this connecting terminal 20, and the fixed contact 5 and the connecting terminal 20 are coupled by terminal screws 22, as shown in FIG.

Next, the operation will be explained. In a normal state, by operating the operating handle 11, the movable contact 8 is opened and closed relative to the fixed contact 5 by the action of a well-known opening/closing mechanism. In this state, the repulsive movable contacts 16a, 16b and the fixed contacts 14a, 14b remain closed. Additionally, when an overload current several times the rated current flows through the circuit, a response device (not shown) is activated and automatically opens the movable contact 8 to interrupt the circuit. In this case, the repulsive movable contacts 16a and 16b remain closed at all times. However, when a large current such as a short circuit current flows, the movable contacts 17 of the repulsion movable contacts 16a and 16b in the current limiter 3
a, 17b are instantaneously separated from the fixed contacts 15a, 15b by electromagnetic repulsion against the urging force of the contact springs 18a, 18b, and an arc is generated between the contacts 15a, 17a and between 15b, 17b. The short circuit current is limited by the arc resistance. After a certain period of time, a response device (not shown) operates and the movable contact 8 in the circuit breaker 2 separates from the fixed contact 5, creating an open circuit between the terminals 12 and 19, causing a short circuit current. A current limiting cutoff is performed. After the interruption is completed, the repulsive movable contacts 16a, 16b are automatically returned to their original positions by the contact pressure springs 18a, 18b.

0004

[Problems to be Solved by the Invention] The above-mentioned circuit breaker 1
The current limiter 3 and the circuit breaker 2 are stacked on top of each other, and the internal mechanisms of each are as shown in FIG. The upper surfaces of the two are connected via a connecting terminal 20. That is,
The bottom surface of this connection terminal 20 is connected to the fixed contact 14 as described above.
The upper surface of the connecting terminal 20 is in contact with the bottom surface of the fixed contact 5, and the fixed contact 5 and the connecting terminal 20 are connected by tightening the terminal screw 22.

However, for example, if the top surface of the connection terminal 20 is not parallel to the bottom surface, the bottom surface of the circuit breaker-side fixed contact 5 will come into contact with the top surface of the connection terminal 20, which is slanted, and the two will not be in surface contact. becomes. In this state, even if the terminal screw 22 is tightened, the connecting terminal 20 is fixed to the current limiter side fixed contact 14a, and this fixed contact 14a has rigidity, so the two surfaces do not make surface contact. This reduces the contact area between the connecting terminal 20 and the fixed contact 5, increases the contact resistance during energization, and as a result, there is a problem in that the temperature rises higher than usual. Also,
If the contact surfaces of the contacts 5 and 14a do not match in position when the circuit breaker housing 4 and the fault current limiter housing 13 are in close contact with each other, the fixed contact 5 may be tilted to the connecting terminal 20 as described above. Otherwise, a gap may be formed in this contact surface, causing the same problem of increased contact resistance as described above or failure to conduct electricity.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to uniformly bring the contact surfaces of a conductor connecting a current limiter and a circuit breaker into close contact with each other without any gaps.

[0007]

[Means for Solving the Problems] A circuit breaker according to the present invention has a conductive structure between a connecting terminal that electrically connects a circuit breaker and a current limiter, and a contact of the circuit breaker or current limiter. A flexible member is provided.

[0008]

[Operation] When the circuit breaker and fault limiter are polymerized to form a circuit breaker with current limiting function, the connection terminal connecting the circuit breaker and fault limiter is brought into contact with the contactor on the fault current limiter side. In this case, even if the contact surface of the connecting terminal is not parallel to the contact or is misaligned, the flexibility of the flexible member interposed between the contact in the current limiter and the connecting terminal Misalignment of the contact member is automatically corrected by utilizing the flexibility, and the flat surface that is the other end surface of the connection member comes into uniform surface contact with the contact on the circuit breaker side or the current limiter side.

[0009]

[Example] Example 1. An embodiment of the present invention will be described based on FIGS. 1 to 3. Incidentally, the same or equivalent parts as those of the conventional one are given the same reference numerals, and the explanation thereof will be omitted. FIG. 1 shows the current limiter 3, in which a flexible member 23 is arranged between the connection terminal 20 and the fixed contact 14a. In this example, a shunt formed by twisting a large number of copper wires is used as the flexible member 23 (hereinafter referred to as a shunt). This shunt 23
Both end portions 23a, 23a are made into a rigid body hardened by applying pressure, and the middle portion is flexible. This shunt 23
As shown in FIG. 2, one of the both ends 23a, 23a of
The one end of the fixed contact 14a is fixed to the step 24 formed at the end of the fixed contact 14a by brazing or the like, and the other end is fixed to the bottom surface of the connection terminal 20 as described above. This flexible member is the shunt 2
3, the position and direction of the upper surface of the connection terminal 20 can be freely changed.

When the fault current limiter 3 is superimposed on the circuit breaker 2 as shown in FIG. . Next, as in the conventional case, the terminal screw 22 is passed through the holes of the fixed contact 5 and the connecting terminal 20, and the terminal screw 22 is tightened. By this tightening, the bottom surface of the fixed contact 5 and the connecting terminal 20
The upper surface (A surface) of is in close contact. At this time, in the present invention, since the shunt 23 is provided between the fixed contact 14a on the fault current limiter 3 side and the connection terminal 20, even if the circuit breaker 2 Even if the bottom surface of the side fixed contact 5 and the A side of the connecting terminal 20 are not parallel or if these both surfaces are misaligned, the flexibility of the shunt 23 will change as the terminal screw 22 is tightened. As a result, the connecting terminal 20 is guided to a direction and position where it makes surface contact with the fixed contact 5. As a result, when the terminal screw 22 is completely tightened, the A surface of the connecting terminal 20 comes into uniform surface contact with the bottom surface of the fixed contact 5.

Example 2. A second embodiment of the shunt 23 is shown in FIG. The shunt 23 in this example is made by stacking several thin copper plates, and both ends 23a, 23
As in the previous embodiment, the portion a is hardened by pressure and fixed to the step portion 24 of the fixed contact 14a and the connecting terminal 20 (see FIG. 5). The intermediate portion of the shunt 23 is a flexible portion. In this embodiment as well, the flexibility of the shunt 23 can be used to bring surface A of the connecting terminal 20 into surface contact with the bottom surface of the fixed contact 5. In addition, in this invention, as a circuit breaker with a current limiting function, one end of the connecting terminal 20 is fixed to a contact in the circuit breaker 2, and has a structure in which it makes surface contact with a contact in the current limiter 3. Good too.

0012

As described above, according to the present invention, there is provided a flexible member having electrical conductivity between the connection terminal that connects the circuit breaker and the current limiter and the contact of the circuit breaker or the current limiter. Since this is provided, when the screw for coupling the circuit breaker and current limiter is fastened, one side of the connecting terminal always comes into uniform surface contact with one side of the contactor on the circuit breaker side. Therefore, there will be no rise in temperature due to poor contact between the contactor on the circuit breaker side and the connection terminal, or failure to conduct electricity due to non-contact.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a current limiter constituting a circuit breaker according to a first embodiment of the present invention.

FIG. 2 is an enlarged side view of a portion centered around a shunt in the current limiter of Example 1.

FIG. 3 is a side view partially showing an internal mechanism, showing a state when the current limiter and circuit breaker of Example 1 are joined.

FIG. 4 is an enlarged side view of a portion centered on a shunt according to a second embodiment of the present invention.

FIG. 5 is a longitudinal cross-sectional view of a current limiter equipped with a shunt in Example 2.

FIG. 6 is a front view of a general circuit breaker with current limiting function.

FIG. 7 is a side view of the circuit breaker.

FIG. 8 is a perspective view showing separately a circuit breaker and a current limiter that constitute a general circuit breaker.

FIG. 9 is a longitudinal sectional view of a conventional circuit breaker with a current limiting function.

[Explanation of symbols]

1 Circuit breaker 2　Breaker 3 Fault limiter 5 Fixed contact 8 Movable contact 14a, 14b Fixed contact 16a, 16b Movable contact 20 Connection terminal 22 Terminal screw 23 Shunt 23a End of shunt

Claims (1)

[Claims] Claim 1: A circuit breaker consisting of a circuit breaker and a fault current limiter, the circuit breaker having a fixed contact that opens by actuation of a response mechanism when an overcurrent flows through the circuit, and a movable contact. The current limiter is equipped with current limiting means for limiting the current when an excessive current such as a short circuit current flows in the circuit, and the circuit breaker and current limiter are provided with respective contacts. A circuit breaker in which circuit breakers are connected to each other via a connecting terminal, characterized in that a flexible member having electrical conductivity is provided between a contactor of the circuit breaker or current limiter and the connecting terminal. circuit breaker.