JPH0227481Y2 - - Google Patents

Description

[Detailed Description of the Invention] Field of the Invention This invention relates to a circuit breaker that opens electrical contacts to interrupt the current when excessive current flows.

Prior Art FIGS. 1 to 4 are diagrams showing conventional circuit breakers that are the background of this invention. FIG. 1 is a side view of a conventional circuit breaker with its side cover removed, and the state shown is an open state.
FIG. 2 is a plan view of the circuit breaker shown in FIG. 1. FIG. 3 is a side view showing essential parts of the circuit breaker of FIG. 1, and the state shown is a closed state. FIG. 4 is a side view showing essential parts of the circuit breaker of FIG. 1, and the illustrated state is an automatic opening state.

As shown in FIGS. 1 and 2, the outer case of the circuit breaker consists of a case 1 made of an insulating material and a side cover 1'. A fixed contact 3 is fixed to one end of the terminal conductor piece 2 to be connected to an external conductor. The other end of the terminal conductor piece 2 forms an external connection terminal portion 2a. A movable contact rod 5 that electrically connects or disconnects the external connection terminal portion 2a.
is displaceably provided. This movable contact rod 5
A movable contact 4 corresponding to the fixed contact 3 is fixed to the lower free end of the movable contact 4 . The movable contact rod 5 is bifurcated from its lower free end toward its upper base end. The opening/closing lever 6 for manually opening/closing the electrical connection state of the circuit breaker has a handle portion 6 that projects outward from the outer box.
a, a U-shaped leg portion 6b, and a shaft portion 6c. The handle portion 6a, the leg portion 6b, and the shaft portion 6c are
It is integrally formed from molded insulator. A recess 6d is provided in the U-shaped leg portion 6b, and a base end portion above the movable contact rod 5 is engaged with this recess 6d.

The trip lever 7 has one end attached to the shaft 8 in the container box 1.
The other end is adapted to engage with a trip piece 17, which will be described later. A kicking member 9 bent into a substantially U-shape is attached to one side of the trip lever 7 via shafts 10 and 11. This straddle member 9 is designed to kick the movable contact rod 5 during automatic opening. The flexible conductor 13 has one end fixed to the movable contact rod 5 and the other end connected to a connecting piece 15 integrally attached to the lower free end of the thermal element 14 .
In this way, the movable contact rod 5 and the thermal element 14 are
Electrical connection is made via the flexible conductor 13. As the thermal element 14, a bimetal is usually used. And its upper end is the terminal conductor 16
It is connected to the.

The trip piece 17 has ears 17a protruding from both side edges near its upper end.
are supported in, for example, triangular recesses provided in the container box 1 and the side lid 1'. In this way, the trip piece 17 is provided so as to be rotatable about the ear piece 17a as a pivot point. The lower end of the trip piece 17 is curved into a hook shape to form a trip piece claw 17b, which engages with the free end of the thermal element 14. A spring 21 is connected to the upper end of the trip piece 17.
The trip piece 17 is always urged to rotate clockwise in the figure.
Further, a locking hole 17c is formed approximately at the center of the trip piece 17, and the tip of the trip lever 7 is releasably engaged with the locking hole 17c. By locking the tip of the trip lever 7 with the lower side of the locking hole 17c, the trip lever 7
clockwise rotation is prevented.

A fixed contact 18 for instantaneous withdrawal is attached near the lower free end of the thermal element 14 made of bimetal. The fixed core 18 constitutes a device for attracting the correspondingly arranged trip piece 17 via the current passing through the thermal element 14, ie a device for instantaneous tripping of the electromagnet. Also, along the movable area of the movable contact 4 of the movable contact rod 5, the isolation chamber 1 is
9 is formed, and an air extinguishing grid plate 20 is disposed within this air extinguishing chamber 19.

The circuit breaker configured in this manner operates as follows. First, when the opening/closing lever 6 is rotated counterclockwise in the open state shown in FIG.
The engaging portion between the opening/closing lever 6 and the movable contact rod 5 similarly rotates counterclockwise. When this engaging portion crosses the line of action of the operating spring 12 to the opposite side, the action of the operating spring 12 causes the movable contact rod 5 to rapidly rotate clockwise. In this way, the movable contact 4 is joined to the fixed contact 3 and the third
The circuit becomes closed as shown in the figure. To change the circuit from the closed state to the open state, the opening/closing lever 6 can be moved clockwise. Then, the operation opposite to the above is performed, and the circuit becomes open again.

Next, the case of automatic opening due to overcurrent or the like will be explained. When a normal overcurrent flows through the thermal element 14 made of bimetal, the thermal element 14 curves and the trip piece claw 17b engages with the lower end of the thermal element 14.
Displace to the right. As a result, the trip piece 17 rotates counterclockwise about the lug 17a, so that the locking hole 17c of the trip piece and the tip of the trip lever 7 are disengaged.

Further, when an excessive current flows, an attractive force is generated between the instantaneous trip fixed iron core 18 and the corresponding piece of the trip piece 17 made of a magnetic material.
As a result, the trip piece 17
The locking hole 17c and the tip of the trip lever 7 are disengaged from each other because the locking hole 17c and the tip of the trip lever 7 are rotated counterclockwise. When the engagement between the locking hole 17c and the tip of the trip lever 7 is released, the trip lever 7 rotates clockwise around the shaft 8 by the force of the operating spring 12 that connects the trip lever 7 and the movable contact rod 5. rotate in the direction. If the connection point between the operating spring 12 and the trip lever 7 moves to the opposite side beyond the engagement portion between the base end of the movable contact rod 5 and the opening/closing lever 6, the movable contact rod 5 It is rotated counterclockwise by the force of the spring and enters the automatic opening state shown in FIG.

Conventional circuit breakers such as those described above have the following drawbacks.

That is, in this type of circuit breaker with a small configuration, the fixed iron core 18 of the instantaneous tripping electromagnet is configured in the form of one turn so as to surround the vicinity of the free end of the thermal element 14 made of bimetal, and the corresponding magnetic It is provided to perform a tripping operation by suctioning a trip piece made of material. Generally, the instantaneous tripping current value is about 10 to 13 times the rated current of the circuit breaker, but depending on the power distribution system or the type of protective equipment, the instantaneous tripping current value may be 3 times the rated current.
In some cases, a value as low as ~4 times is required. In conventional circuit breakers, in order to meet this requirement, it was necessary to take measures such as increasing the number of ampere turns by winding the main current coil around the fixed core a suitable number of times, thereby increasing the attractive force. However, in a circuit breaker configured to tightly accommodate components in a limited space, it is difficult to wind the main current coil around the fixed core for instantaneous tripping a suitable number of times.
This is difficult due to space limitations. Furthermore, in order to do so, there was a problem in that it could not be solved by simply performing additional processing on the conventional product, and the conventional product had to be significantly modified.

Purpose of the invention Therefore, the purpose of this invention is to create a circuit that can reduce the instantaneous tripping current value with a simple configuration without having to wind the main current coil an appropriate number of times around the fixed core of the instantaneous tripping electromagnet device. The purpose is to provide circuit breakers.

In summary, this invention consists of a first device which is arranged so as to surround the vicinity of the free end of the thermal element and which is configured to attract the trip piece by electromagnetic force.
In addition to the fixed iron core, a second core is arranged so as to surround the thermal element portion located near the pivot point of the trip piece, and is configured to attract the portion near the pivot point of the trip piece by electromagnetic force. This is a circuit breaker further equipped with a fixed iron core. Therefore, when an excessive current flows, the trip piece is attracted to the first fixed iron core and the second fixed iron core, thereby releasing the engagement between the trip piece and the trip lever.

DESCRIPTION OF THE EMBODIMENT FIGS. 5 to 7 show an embodiment according to this invention. FIG. 5 is a side view of an embodiment of this invention with the side cover removed, and the state shown is an open state. Figure 6 shows the fifth
FIG. 2 is a side view showing essential parts of the circuit breaker shown in the figure, and the illustrated state is an automatic opening state. FIG. 7 is an exploded perspective view of essential parts of the circuit breaker of FIG. 5. In the drawings, the same numbers as those used in FIGS. 1 to 4 indicate the same or corresponding parts.

The illustrated circuit breaker is rotatably provided, and electrical contacts are opened when the circuit breaker is rotated in a predetermined direction, similar to the conventional circuit breaker explained using FIGS. 1 to 4. With Tritup Lever 7,
A trip piece 1 made of a magnetic material, rotatable about a pivot point, and engaged with a trip lever 7 when in a predetermined position to inhibit rotation of the trip lever 7.
7, a spring 21 which urges the trip piece 17 to rotate back to a position where it can always be engaged with the trip lever 7, and a spring 21 which extends parallel to the trip piece 17 and has one end fixed and the other end free. The first fixed core 18 is arranged to surround the vicinity of the free end of the thermal element 14 and is configured to attract the trip piece 17 by electromagnetic force. ing. As the thermal element 14, for example, bimetal is used.

The difference between the illustrated embodiment and the conventional circuit breaker is that a second fixed core 30 is newly provided. That is, the second fixed iron core 30 is arranged relatively close to the pivot point 17a of the trip piece 17, surrounding the bimetallic thermal element 14, and corresponding to the trip piece 17. As is clear from FIG. 7, a mounting hole 30a is formed in the center of the second fixed core 30, and a protruding member 16a is provided on the terminal conductor 16 in connection therewith. Therefore, the second fixed iron core 30 has the protruding member 16 in its mounting hole 30a.
The terminal conductor 16 is attached to the terminal conductor 16 by inserting the terminal a and then caulking it.

When an excessive current flows through the circuit breaker having such a configuration, the first fixed core 18 and the second fixed core 30 for momentary tripping are excited, and the trip piece 17 is attracted accordingly. Therefore, the trip piece 17 rotates counterclockwise in the figure using the lug 17a as a fulcrum, and as a result, the engagement between the locking hole 17a and the tip of the trip lever 7 is released. Then, the movable contact rod 5 is moved to the open position, and the movable contact 4 is separated from the fixed contact 3, resulting in the automatic open state shown in FIG. 6.

Effects of the invention As described above, according to this invention, in addition to the first fixed core for instantaneous tripping, which has been used conventionally, a part near the rotational fulcrum of the trip piece is attracted by electromagnetic force. Since the second fixed core is further provided with a second fixed core configured as shown in FIG.
The instantaneous tripping current value can be set low. In fact, when a second fixed core was added to a device that had only the first fixed core and its instantaneous tripping current value was about 1300A, the instantaneous tripping current value increased.
I was able to lower it to around 400A.

Furthermore, since the second fixed iron core is provided near the pivot point of the trip piece, the suction stroke of the second fixed iron core relative to the trip piece, which is required to disengage the trip piece and the trip lever, is reduced. be able to. Therefore, the gap between the second fixed iron core and the trip piece can be set small, and as a result, the magnetic flux passing through the trip piece increases, the attractive force increases, and the instantaneous tripping current increases in cooperation with the first fixed iron core. Effectively contributes to lowering the value.

[Brief explanation of the drawing]

FIG. 1 is a side view of a conventional circuit breaker with its side cover removed, and the state shown is an open state. FIG. 2 is a plan view of the circuit breaker shown in FIG. 1. FIG. 3 is a side view showing essential parts of the circuit breaker of FIG. 1, and the state shown is a closed state. FIG. 4 is a side view showing essential parts of the circuit breaker of FIG. 1, and the illustrated state is an automatic opening state. FIG. 5 is a side view of one embodiment of this invention with the side cover removed, and the state shown is an open state. FIG. 6 is a side view showing essential parts of the circuit breaker of FIG. 5, and the illustrated state is an automatic opening state. 7th
The figure is an exploded perspective view of the main parts of the circuit breaker of FIG. 1. In the figure, 7 is a trip lever, 14 is a thermal element, 17 is a trip piece, 18 is a first fixed core, 21 is a spring, and 30 is a second fixed core.

Claims (1)

[Claims for Utility Model Registration] A fixed contact and a movable contact constituting an electric contact, a thermal element whose one end is fixed and the other end is free, and the thermal element is made of a magnetic material and a trip piece arranged to extend in parallel and rotatable about a rotation fulcrum; a trip lever that is provided in conjunction with the movable contact so as to move the trip piece apart, and whose rotation is normally prohibited by engaging with the trip piece; and a trip lever that is configured to rotate the trip lever in a predetermined direction. a spring fixed to the thermal element, which is excited when an excessive current flows to attract the trip piece by electromagnetic force, and engages the trip piece with the trip lever; A circuit breaker comprising: a fixed core that releases a state; and a first fixed core arranged to surround the vicinity of the free end of the thermal element; and a circuit breaker that is separated from the first fixed core. Located in
A circuit breaker comprising: a second fixed iron core disposed so as to surround the thermal element portion located near the rotational fulcrum of the trip piece.