JPH0155740B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an arc extinguishing device for a multiple contact type circuit or breaker.

[Prior Art] A multi-contact type circuit breaker, in which the main contact first separates in the opening operation, and then the auxiliary contact separates after a delay, is effective in extending the life of the contact portion. (For example, JP-A-47-16966) In the opening operation, it is also effective to insert a coil in series in the electric circuit in order to increase the opening speed of the movable contact and to limit short circuit current. (For example, Japanese Utility Model Application No. 18963) It becomes effective.

[Problems to be Solved by the Invention] Even in multi-contact type circuits and disconnectors, arcing also occurs at the main contacts when a large current is interrupted. In this case, if the arc does not move quickly to the auxiliary contact,
The main contacts become severely worn out and their current carrying performance deteriorates, and the auxiliary contacts no longer work effectively to extinguish the arc. Assuming that an arc is generated at the main contact as exemplified in the prior art section, it is difficult to say that the arc will quickly move to the auxiliary contact with this arrangement of both the main and auxiliary contacts.

The present invention has been made in view of the above reasons, and its purpose is to quickly transfer the arc to the auxiliary contact even if an arc occurs at the main contact, thereby improving arc extinguishing performance. The purpose of the present invention is to provide arc extinguishing devices for circuits and breakers.

[Means for Solving the Problems] In order to solve the problems, the arc extinguishing device for circuit breakers of the present invention includes a fixed contact 1 having a main fixed contact 1a, and a main Movable contact 4
A movable contact 4 having a contact point 4a and an auxiliary stationary contact 9a extending from the lowest stage of the arc-extinguishing grid blocks stacked at predetermined intervals in the direction in which the two main contacts 1a, 4a are located. The running plate 9 is electrically connected to the movable contact 4, and the base end is rotatably supported by the tip of the movable contact 4, and the auxiliary fixed contact 9a is attached to the tip.
an auxiliary movable contact 5 which is provided with an auxiliary movable contact 5a that separates from the auxiliary movable contact 5a, and which is biased by a spring in a direction in which the auxiliary movable contact 5a presses the auxiliary fixed contact 9a;
A yoke 10 formed into a U-shape by both opposing pieces and a connecting piece 10a, and arranged so that both opposing pieces sandwich the auxiliary contacts 9a and 5a, and a connecting piece 10a of the yoke.
is wound around the running plate 9 at one end and the fixed contact 1 at the other end.
It is a circuit and disconnector in which both the auxiliary contacts 9a, 5a are separated after the main contacts 1a, 4a are separated in the opening operation, and the auxiliary contacts 9a, 5a are separated from each other. The extending end portion 9b of the plate 9 extends from the position where the auxiliary fixed contact 9a is provided to a position approximately perpendicular to the arc generated between the two main contacts 1a and 4a, and extends from the position where the auxiliary fixed contact 9a is provided, and extends to the vicinity where the main movable contact 4a is substantially perpendicular to the arc generated between the two main contacts 1a and 4a.
The contact surface X of the main fixed contact 1a in the direction of separation of
The distance L between the extending end portion 9b and the surface of the extending end portion 9b is set to 2 to 3 mm.

[Function] In the opening operation, when an arc occurs between the main contacts 1a and 4a, the extending end 9b is located near the arc and substantially perpendicular to the arc, and furthermore, the extending end 9b is located near the arc and substantially perpendicular to the arc. An appropriate electric field strength is generated between them, so that the arc quickly moves to the extending end 9b and then to both auxiliary contacts 9a and 5a.

[Example] Hereinafter, an example of the present invention will be described based on FIGS. 1 and 2.

A fixed contact 1 has a main fixed contact 1a at its tip. A connecting conductor 2 is fixed to the base end of the fixed contact 1, and this connecting conductor 2 is connected to one terminal 3.

Reference numeral 4 denotes a movable contact, which is disposed overlappingly and substantially parallel to the fixed contact 1, and has a main movable contact 4a at its tip that separates from the main fixed contact 1a. The movable contactor 4 is driven by a general contact opening mechanism (not shown), and is electrically connected to the other terminal (not shown) via a conductive member (not shown).

Reference numeral 9 denotes a traveling plate, which extends from the lowest stage of the arc-extinguishing grid blocks stacked at predetermined intervals in the direction in which both main contacts 1a and 4a are located, and extends in the intermediate portion before the extending end 9b. An auxiliary fixed contact 9a is provided. The detailed structure of this running plate 9 will be described later.

Reference numeral 5 denotes an auxiliary movable contact, in which a shaft 7 at the base end is rotatably supported by the tip of the movable contact 4, and the tip is provided with an auxiliary movable contact 5a that separates from the auxiliary fixed contact 9a. be. This auxiliary movable contact 5 is
A tension spring 8 tensioned between itself and the movable contact 4 causes the auxiliary movable contact 5a to connect to the auxiliary fixed contact 9a.
is biased by a spring in the direction of pressing (direction of arrow P), and this pressing force acts as contact pressure between both auxiliary contacts 9a, 5a. Also, the auxiliary movable contact 5
is electrically connected to the movable contactor 4 by a flexible conductor 6.

10 is a yoke, which is formed into a U-shape by both opposing pieces and a connecting piece 10a, and both opposing pieces connect to both auxiliary contacts 9a, 5.
They are arranged so as to sandwich a.

A coil 11 is wound around the connecting piece 10a of the yoke a predetermined number of times, and has one end connected to the running plate 9 and the other end connected to the fixed contact 1.

Next, the detailed configuration of the running plate 9 will be explained. That is, the extending end 9b of the running plate 9 is connected to the auxiliary fixed contact 9a.
The contact surface X of the main stationary contact 1a and the extended end 9b extend from the position where the contact surface X of the main fixed contact 1a and the extended end 9b extend from the position where the contact surface X of the main fixed contact 1a is further extended to the vicinity substantially perpendicular to the arc generated between the two main contacts 1a and 4a, and in the direction of separation of the main movable contact 4a. The distance L between the surfaces is set to 2 to 3 mm.

Such a circuit breaker operates as follows.

Figure 1 shows the closed state, with both main contacts 1a and 4
a, both auxiliary contacts 9a and 5a are connected.
Therefore, most of the current flows through the main contacts 1a, 4a.

In this state, when a large current such as a short-circuit current flows and the movable contact enters the opening operation, first, as shown in Figure 2 A,
The main movable contact 4a is separated from the main fixed contact 1a.
At this time, the larger the current, the more likely an arc will occur between the main contacts 1a and 4a. This arc is a→b
and eventually moves to the extended end portion 9b as shown in c. Then, as shown in FIG. 2B, the auxiliary movable contact 5a separates from the auxiliary fixed contact 9a after a delay. At this time, the arc moves from d to e and is current limited and extinguished by the arc extinguishing grid block.

To explain in more detail the state shown in FIG.
mm, the electric field strength between the arc and the extending end 9b is of an appropriate magnitude, making it easy for the arc to move to the extending end 9b. When this distance L is made smaller than 2 to 3 mm, the electric field strength between the arc and the extending end 9b becomes smaller, making it difficult for the arc to migrate.On the other hand, when the distance L is made larger than 2 to 3 mm, the arc is moved to the extended end. The time required for the main movable contact 4a to reach the separated position before touching the portion 9b becomes longer, and the transition of the arc becomes slower. That is, when the distance L is set to 2 to 3 mm, the transition of the arc occurs most quickly and smoothly, and therefore the arc voltage rises quickly and a high current limit is achieved.

FIG. 3 shows data showing the experimental results regarding the distance L, where A is the data of the present invention and B is data outside the scope of the present proposal. The cutoff condition is a standard current of 32KA/
It was set to 220V. Also, i is the load current, v is the arc voltage, and v0 is the recovery voltage. From this data, comparing the rise time for the arc voltage to 150V, the former is 3.6 msec, the latter is 4.0 msec,
The proposed one is 0.4 msec faster.

[Effects of the Invention] Since the arc extinguishing device for circuit breakers and circuit breakers of the present invention is configured as described above, in the opening operation,
When an arc occurs between the main contacts, the extended end is located near the arc and approximately perpendicular to the arc, and an appropriate electric field strength is generated between the arc and the extended end. Therefore, the arc quickly moves to the extending end and to both auxiliary contacts 9a, 5a, thereby improving the arc extinguishing performance.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of the present invention, Fig. 2 A and B are explanatory diagrams of its opening operation, and Fig. 3 is an arc voltage characteristic diagram, A is the present invention and B is not the present invention. thing. 1... Fixed contact, 1a... Main fixed contact, 4...
...Movable contact, 4a...Main movable contact, 5...Auxiliary movable contact, 5a...Auxiliary movable contact, 9...Travel plate, 9a...Auxiliary fixed contact, 9b...Extending end,
DESCRIPTION OF SYMBOLS 10... Yoke, 10a... Connection piece, 11... Coil, L... Distance, X... Surface of main fixed contact.

Claims (1)

[Scope of Claims] 1. A fixed contact having a main fixed contact, a movable contact having a main movable contact that separates from the main fixed contact, and the lowest stage of arc-extinguishing grid blocks stacked at a predetermined interval. a running plate extending in the direction in which both of the main contacts are located and provided with an auxiliary fixed contact; and a running plate electrically connected to the movable contact, the base end of which is connected to the tip of the movable contact. The auxiliary movable contact is rotatably supported by the auxiliary movable contact, is provided with an auxiliary movable contact at its tip portion to separate from the auxiliary fixed contact, and is spring-biased in a direction in which the auxiliary movable contact presses the auxiliary fixed contact. , a yoke formed in a U-shape by both opposing pieces and a connecting piece, and both opposing pieces are arranged so as to sandwich both the auxiliary contacts, and a connecting piece of the yoke is wound around, and one end is fixed to the running plate and the other end is fixed. A circuit breaker or breaker consisting of coils each connected to a contactor, and in which both auxiliary contacts separate after a delay after both main contacts separate in the opening operation, and the extending end of the running plate The section further extends from the position where the auxiliary fixed contact is provided to the vicinity substantially perpendicular to the arc generated between the two main contacts, and is in contact with the contact surface of the main fixed contact in the direction of separation of the main movable contact and the extending end. An arc extinguishing device for a circuit or disconnection characterized by having a distance between surfaces of 2 to 3 mm.