JPS648890B2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a circuit breaker, and more specifically, it is provided with a main contact and an auxiliary contact, and the electrical connection between the main contact and the auxiliary contact is made in parallel via a coil. The present invention also relates to a circuit breaker that transfers the arc generated at the auxiliary contact to the arc extinguishing device side by the magnetic driving force caused by the magnetomotive flux of the coil when the auxiliary contact is opened due to the flow of a large current.

BACKGROUND ART Conventionally, in such a circuit breaker, a yoke has been inserted into a coil in order to increase the magnetic flux, and the coil has been wound around a connecting portion connecting a pair of legs of the yoke. Therefore, there was a drawback that magnetic flux density in the hollow part could not be obtained sufficiently due to magnetic saturation of the connecting part.

Purpose The purpose of the present invention is to solve the above-mentioned technical problem,
It is an object of the present invention to provide a circuit breaker with increased arc driving force and improved arc extinguishing function.

Embodiment FIG. 1 is a simplified cross-sectional view of a circuit breaker according to an embodiment of the present invention. This circuit breaker 1 is provided with a fixed contact plate 3 extending along a synthetic resin device stand 2. The fixed contact plate 3 has its base end 3a connected to the power supply side terminal fitting 4, and its free end 3b is bent into a U-shape. This free end 3b is provided with one main contact 5 that serves as a fixed contact. Main contact 6 which is another movable contact that comes into contact with this main contact 5
is provided on the movable contact plate 7. The movable contact plate 7 is connected to a load-side terminal fitting. By bending one end of the fixed contact plate 3 into a U-shape in this way, the directions of the current flowing through the movable contact plate 7 and the fixed contact plate 3 are opposite to each other, so that when a large current is applied, the current flows in the opposite direction. An electromagnetic repulsive force acts due to the magnetomotive flux, and the opening speed of the movable contact plate 7 can be improved.

A relay terminal plate 8 is provided above the flat plate portion 3c of the fixed contact plate 3 in FIG. 1 and on an extension of the free end 3b of the fixed contact plate 3. This relay terminal board 8 is provided with an auxiliary contact 9. An auxiliary movable contact plate 10 is disposed above the relay terminal plate 8 in FIG.
will be provided. The relay terminal plate 8 and the auxiliary movable contact plate 10 are inserted between the legs 13 and 14 of the U-shaped yoke 12 as shown in the second figure, and the auxiliary contact 9 of the relay terminal plate and the auxiliary movable contact plate 10
An auxiliary contact 11 is interposed between the legs 13 and 14 of the yoke 12. Legs 13 and 14 of this yoke 12
A coil 15 is wound around.

The auxiliary contact 9 is electrically connected to the main contact 5 on the fixed contact side. Further, the auxiliary contact 11 is electrically connected to the main contact 6 on the movable contact side. More specifically, one end of the coil 15 is connected to the relay terminal plate 8, and the other end is connected to the free end 3b of the fixed contact plate 3, thereby connecting the auxiliary contact 9 and the main contact 5. electrically connected. Further, an L-shaped piece 16 is provided on the surface of the auxiliary movable contact plate 10 opposite to the surface on which the auxiliary contact 11 is provided, and the movable contact plate 7 also has an L-shaped piece 16 similar to the L-shaped piece 16. A piece 17 is provided. The L-shaped piece 16 and the L-shaped piece 17 are connected by a braided wire 18. This electrically connects the auxiliary contact 11 and the main contact 6. The auxiliary movable contact plate 10 and the movable contact plate 7 are connected by a connecting piece 19. This connecting piece 19
is swingable around the axis of the shaft 20a. Therefore, when a large current such as a short-circuit current or an overload current flows, the opening of the auxiliary movable contact plate 10 is delayed by the connecting piece 19 when the main contacts 6 and 5 perform the opening operation. This generates an arc on the side of the auxiliary contacts 9 and 11, so the contacts 9 and 11 are made of a high melting point metal, such as tungsten or an alloy thereof, to reduce the generation of metal vapor and reduce the vapor density. This improves the cut-off conditions.

An arc extinguishing device 20 is provided on the left side of the auxiliary movable contact plate 10 in FIG. The arc extinguisher 20 includes a plurality of grids 21 stacked at regular intervals in the vertical direction of FIG.

A short circuit current is applied to the circuit breaker 1 having such a configuration.
When a large current such as an overload current flows, the movable contact plate 7 on the main contact side first performs an opening operation. At this time, the auxiliary contact 11 is still connected to the auxiliary contact 9 by the connecting piece 19 in the initial stage of the opening operation. Therefore, a large current flows in the order of fixed contact plate 3 → coil 15 → relay terminal plate 8 → auxiliary contact 9 → auxiliary contact 11 → auxiliary movable contact plate 10 → braided wire 18 → movable contact plate 7. At this time, a magnetomotive flux is generated in the coil 15, and the magnetomotive flux acts to magnetically drive the arc generated between the auxiliary contacts 9 and 11 toward the arc extinguisher 20 side. Thereafter, the arc current flows through the arc extinguishing device 20 and is quickly extinguished.

FIG. 3 is a perspective view of the vicinity of the yoke 12. In addition, in FIG. 3, the auxiliary contacts 9 and 11 are in an open state. An excitation coil 15 is wound around the legs 13 and 14 of the yoke 12, so that magnetic flux is generated in the direction indicated by the arrow 25 when the auxiliary contacts 9 and 11 are opened. The arc is moved in the direction indicated by arrow 26, that is, toward the arc extinguishing device 20 side, by the magnetic driving force caused by this magnetomotive flux. By winding the coil 15 around the legs 13 and 14 of the yoke 12 in this manner, it is possible to increase the magnetic flux density of the air in the yoke 12, thereby increasing the arc driving force and improving the performance. It is possible to obtain excellent arc-extinguishing performance.

FIG. 4 is a simplified cross-sectional view of a circuit breaker according to another embodiment of the invention. This embodiment is similar to the previous embodiment and corresponding parts are provided with the same reference numerals. In addition, in FIG. 4, the auxiliary movable contact plate, the movable contact plate, and structures related thereto are omitted for ease of illustration. It should be noted that in this embodiment, a flat coil 30 is used in place of the coil 15 in the previous embodiment. As shown in FIG. 5, this flat coil 30 includes a flat coil body 31 made of a conductive material such as copper, which is bent into an S-shape, and a free end 3b of the coil body 31 and the fixed contact plate 3. conductive plate 32 for electrically connecting
including. The coil main body 31 is arranged on the lower surface of the relay terminal plate 8, and one end 31a is fixed to the relay terminal plate 8 by welding or the like. A conductive plate 32 is arranged on the lower surface of the coil body 31, and one end 32a of the conductive plate 32 is fixed to one end 31b of the coil body 31 by welding or the like. An insertion hole 33 is formed in the other end 32b of the conductive plate 32.
A screw 34 is inserted through and screwed onto the free end 3b of the fixed contact plate 3. In this way, the auxiliary contact 9 is electrically connected to the main contact 5.

The opening 3 of the coil 30 having such a configuration
5, 36, the leg portion 1 of the yoke 12 as shown in the sixth figure.
3 and 14 are inserted gently. In this way, in this embodiment, the flat coil 30 is used as the coil around which the yoke 12 is wound, so that the installation work is simple and the work time can be shortened.

FIG. 7 is a simplified cross-sectional view of a circuit breaker according to still another embodiment of the present invention. This embodiment is similar to the previous embodiment and corresponding parts are provided with the same reference numerals. What should be noted is that the legs 13 of the yoke 12,
A protruding part 41 extending in a direction perpendicular to the longitudinal direction of the connecting part 40 is integrally formed on the connecting part 40 that connects the two parts.
a extends to the vicinity of the curved portion 3d of the fixed contact plate 3.

By providing the protrusion 41 in this way,
The cross-sectional area of the connecting portion 40 of the yoke 12 is increased, which improves the magnetic saturation of the connecting portion 40 during overload currents, and therefore increases the magnetic flux density in the air gap sufficiently to drive the arc generated between the main contacts 5, 6. It becomes possible to increase the

Effects As described above, according to the present invention, the magnetic driving force of the magnetomotive flux due to the large current can be increased.
The arc can be transferred to the arc extinguishing device in a short time and effectively.

[Brief explanation of the drawing]

FIG. 1 is a simplified sectional view of a circuit breaker according to an embodiment of the present invention, FIG. 2 is a view taken from the plane line - in FIG. 1, FIG. 3 is a perspective view of the vicinity of the yoke 12, and FIG. 4 5 is a simplified cross-sectional view of a circuit breaker according to another embodiment of the present invention, FIG. 5 is an exploded perspective view of the flat coil 30, and FIG. 6 is a diagram for explaining the mounting state of the yoke 12 and the flat coil 30. 7 are simplified cross-sectional views of a circuit breaker according to still another embodiment of the present invention. 1... Circuit breaker, 3... Fixed contact plate, 3d... U
Character-shaped part, 5, 6... Main contact, 9, 11... Auxiliary contact, 12... Yoke, 13, 14... Leg part, 1
5, 30... Coil, 20... Arc extinguishing device, 40...
...Connection part.

Claims (1)

[Scope of Claims] 1 Main contacts facing each other so as to be separated from each other, electrically connected to each of the main contacts as a pair,
An auxiliary contact that is connected together with the main contact at rated current and opens after the main contact opens, a coil that is provided on the auxiliary contact side and has a yoke inserted, and a coil that is connected to the main contact and the auxiliary contact. One side of the electrical connection with the contact is made in parallel through the coil, and when the large current flows and the auxiliary contact opens, an arc is generated at the auxiliary contact due to the magnetic driving force due to the magnetic flux of the coil. In the circuit breaker, the yoke includes a pair of legs and a connecting part that connects the legs, and the coil is wound around the legs,
Furthermore, the circuit breaker is characterized in that the tip of the fixed contact plate to which the main contact is fixed is formed into a U-shape.