JPH0112765Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a circuit breaker that can improve the breaker performance.

Conventionally, this type of breaker is shown in Figures 1 and 2.
I got what is shown in the figure. That is, in the figure, 1 is a handle formed of an insulating material and pivots to open and close the circuit from the outside, 2 is a trip lever that pivots about a shaft 3, and 4 is an actuating plate, which is rotatable by a support portion 4A. It is formed by a locking part 4B that is held and locks the tip of the tripping lever 2, and a bent part 4c that has one end bent into a substantially U-shape. 5 is a compression spring that always urges the actuating plate 4 clockwise around the support portion 4A; 6 is a bimetal whose one end is fixed to the load terminal 7 and the other end faces the bent portion 4c of the actuating plate 4;
Reference numeral 8 indicates an iron piece that is fixed to the bimetal 6 and is excited by an overcurrent to attract the actuating plate 4. Reference numeral 9 indicates an adjustment screw that adjusts the relationship between the bending portion 4c of the actuating plate 4 and the bimetal 6. Reference numeral 10 indicates an external conductor (not shown). 11 is a movable conductor with one end in contact with the bottom 1A of the handle 1 and a movable contact 12 fixed to the other end; 13 is the first through hole 2A of the tripping lever 2; and a second through hole 11A of the movable conductor 11, the tension spring urges the tripping lever 2 clockwise and brings one end of the movable conductor 11 into elastic contact with the bottom 1A of the handle 1. , 14 is a movable contact 12
16 is a tightening screw for screwing a power conductor (not shown); 17 is an auxiliary lever; one end 17A
is engaged with the housing 18, and the other end 17B faces the surface of the movable conductor 11 to which the movable contact 12 is fixed. Reference numeral 17c denotes a bent portion formed approximately at the center of the auxiliary lever 17, which is rotatably inserted into the third through hole 2B of the tripping lever 2. 19 is a flexible conductor connected to the movable conductor 11 and the bimetal 6, and 20 is an arc extinguishing device in which grids 20A are arranged in parallel at predetermined intervals and fixed by an insulating plate 20B.

Next, the operation in such a configuration will be explained. When an overcurrent such as a short circuit occurs, this overcurrent flows through the power terminal 14 - fixed contact 15 - movable contact 12 - movable conductor 11, and then flows through the flexible conductor 1.
9 to the bimetal 6 and load terminal 7. This overcurrent magnetizes the iron piece 8 fixed to the bimetal 6, attracts the actuating plate 4, and causes it to rotate counterclockwise about the support portion 4A of the actuating plate 4. For this reason, the tip of the tripping lever 2 comes off the locking part 4B of the actuating plate 4, and in order to change the biasing direction of the tension spring 13 and rotate the movable conductor 11, the movable contact 1
2 is separated from the fixed contact 15. In addition, in the initial stage of separation between the movable contact 12 and the fixed contact 15, in order to quickly separate the movable conductor 11, the auxiliary lever 1
The other end 17B of 7 kicks up the movable conductor 12 in the opening direction. In this way, an arc is generated between the movable contact 12 and the fixed contact 15, but this arc is attracted by the variable distortion magnetic field of the arc created by the grid 20A that constitutes the arc extinguishing device 20, and is separated and cooled. Cut off the current.

The above is the operating principle of the conventional circuit breaker.
In such circuit breaks and breakers, especially when the fault current is large, arcs not only occur between the movable contact 12 and the fixed contact 15, but also between the fixed conductor 14 and the other end 17B of the auxiliary lever 17. It also occurs. Therefore, the fault current flows from the fixed conductor 14 to the auxiliary lever 17, the tripping lever 2, the operating plate 4, and the bimetal 6.
- It flows to the load terminal 7 and arcs and welds at the engagement portion between the tripping lever 2 and the actuating plate 4. In addition, the fault current flows between the fixed conductor 14 - the auxiliary lever 17 - the tripping lever 2
- the flow is diverted to the tension spring 13 and the tension spring 13 is melted; Furthermore, the other end 17B of the auxiliary lever 17 is melted due to arc generation, and the length from the bent portion 17c to the other end 17B is shortened, so that the other end 17B is shortened.
7B had a drawback that the timing of kicking up the movable conductor 11 was delayed.

This invention was devised to eliminate such conventional drawbacks, and will be described below with reference to FIG. 8 showing an embodiment of this invention. That is, in the figure, 21 is a support shaft made of an insulating material formed by a large diameter portion 21A and small diameter portions 21B at both ends following the large diameter portion 21A, and 22 is one small diameter portion 21A.
The auxiliary lever 22A is rotatably fitted into the other small diameter part 21A of the support shaft 21 fitted into the through hole of the lever 2, and 22A is one end of the auxiliary lever 22 engaged with the fixed part of the housing 18. 22B is the other end of the auxiliary lever 22 facing the mounting surface of the movable contact 12 of the movable conductor 11. The other components are the same as those of the conventional one, and therefore their explanation will be omitted.

Next, the operation configured in this way will be explained.
Overcurrent due to short-circuit current, etc. is the same as in the prior art, including power supply terminal 14, fixed contact 15, movable contact 12, and movable conductor 11, so explanation thereof will be omitted. An arc is generated between the fixed contact 15 and the movable contact 12, which are opened due to the overcurrent flowing in this manner, but is extinguished by the arc extinguishing action of the arc extinguishing device 20. Therefore, in addition to the arc that occurs between the fixed contact 15 and the movable contact 12 that are opened, if we look at the action between the stationary conductor 14 and the other end 22B of the auxiliary lever 22, where arcs are likely to occur, The longer the length from the center of the support shaft 21 on which the auxiliary lever 22 is fitted to the other end 22B, the more effectively the movable conductor 11 exerts the opening action by the lever action of the support shaft 21. can do. However, it is clear that if the other end 22B is made longer and closer to the fixed contact 14, arcing is more likely to occur. However, in this invention, since the support shaft 21 made of an insulating material is provided between the auxiliary lever 22 and the tripping lever 2, there is no potential difference between the fixed conductor 14 and the auxiliary lever 22, so no arc occurs. do not. Further, the same effect can be obtained by forming the shaft and the auxiliary lever from a strong insulating material.

As described above, according to this invention, since the trip lever and the auxiliary lever are insulated by the support shaft, the tripping lever cannot be tripped by the arc generated between the fixed conductor and the auxiliary lever, unlike the conventional method. The tip of the lever, the tension spring, the other end of the auxiliary lever, etc. will not be melted, and the length from the center of the spindle to the other end of the auxiliary lever will not change, reducing the risk of circuits and disconnections. This has various effects such as improving cutting performance, and by making the other end of the auxiliary lever longer, the cutting performance of the auxiliary lever can be further improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional circuit breaker, Figure 2 A and B both show the main parts of the conventional circuit breaker, and Fig. 2 A is a side view. Figure 2 (B) is a front view, and Figures 3 (A), (B), and (C) all show an embodiment of this invention, and Figure 3 (A) shows the state in which the tripping lever is locked to the operating plate. FIG. 3(b) is a front view, FIG. 3(b) is a side view thereof, and FIG. 3(c) is a front view showing a state in which the tripping lever is released from the actuating plate. In the figure, 1 is a handle, 2 is a tripping lever, 4 is an actuation plate, 11 is a movable conductor, 12 is a movable contact, 13
is a tension spring, 14 is a power terminal, 15 is a fixed contact,
22 is an auxiliary lever, and 22B is the other end. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] A trip lever that can rotate freely around one side as a fulcrum, an actuating plate that locks or unlocks the other side of this trip lever, a movable conductor that has one side in contact with the handle and a movable contact fixed to the other side, and both ends of the lever. Each comprises a tension spring hooked to the tripping lever and the movable conductor, a power supply terminal having a fixed contact fixed opposite to the movable contact, and an insulating material fitted near the pivot point of the lever. a support shaft, an auxiliary lever rotatably fitted onto the support shaft, one of which is engaged with a fixed part, and the other of which is opposed to the movable contact fixing surface of the movable conductor, the tripping lever and the actuating plate; A circuit breaker or circuit breaker, characterized in that the auxiliary lever kicks up the movable conductor in an opening direction when the movable conductor is released from the lock.