JPH0136654B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application) The present invention relates to an arc extinguishing device for a circuit or breaker that divides and interrupts an arc using a grid when the circuit or breaker is opened.

(Problems with the prior art) Both the fixed and movable contacts of this type of circuit breaker are
Generally, they are divided into main contacts for the main circuit and auxiliary contacts for arc cutting. In other words, closed pole (insertion)
Sometimes, contact is made in the order of auxiliary contact → main contact, and when opening (breaking), the main contact → auxiliary contact is used for opening, and the auxiliary contact is made of a contact material with good arc resistance. It is intended to reduce wear and deterioration of the main contacts due to arcing when short circuit current is interrupted.

However, in reality, depending on the impedance relationship between the main contact and the auxiliary contact, an arc occurs at both contacts, and furthermore, the arc generated at the main contact does not extinguish until the current reaches zero, so that the above intention is not met. It has not been fully achieved.

(Purpose) The present invention has been made in view of the above points, and its purpose is to extinguish the arc by reliably transferring the arc to the auxiliary contact at the time of contact opening, thereby reducing wear and deterioration of the main contact. The purpose is to provide equipment.

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

1 is the main body of the cutter, which is composed of a housing and a stand 2 and a cover 3. 4 is the power supply side terminal device,
Reference numeral 5 denotes a load side terminal device, both of which are installed on the device stand 2.

Reference numeral 6 denotes a terminal plate connected to the power supply side terminal device 4, and is provided with fixed contacts divided into a main fixed contact 7a made of a low resistance material and an auxiliary fixed contact 7b made of a high melting point material.

Reference numeral 9 denotes a movable contact plate whose base end is pivotally supported by a shaft 10, and a movable contact plate divided into a main movable contact 8a made of a low resistance material and an auxiliary movable contact 8b made of a high melting point material is provided at the free end. .

Reference numeral 11 denotes a drive section of the handle 12, which includes a movable contact plate 9.
The intermediate portion of the shaft is pivotally supported by a link 13 and a shaft 14, and the link maintains a balanced state when the pole is closed.
Reference numeral 15 denotes an overcurrent detection element such as an electromagnetic device, which is activated when a large current flows and disturbs the symmetry of the handle drive unit 11. Therefore, the movable contact plate 9 is connected to the link 13 by the operation of the handle drive unit 11. The free end is lifted up, and the main and auxiliary movable contacts 8a and 8b are
The auxiliary fixed contacts 7a and 7b are opened.

A plurality of arc extinguishing grids 16 are stacked to form an arc extinguishing device 17, and this arc extinguishing device 17 is disposed near both auxiliary contacts 7b and 8b.

A first link 19 has one end pivotally supported by a shaft 20 at an intermediate portion of the movable contact plate 9, which is different from the shaft 14. 21 is a second link, one end of which connects the shaft 22 to the table 2.
It is supported by A receiving portion 24 guided by a guide 25 provided on the instrument stand 2 is pivotally supported at the intermediate portion of the second link 21 .

Reference numeral 18 denotes a rigid shielding plate made of an insulator, with the tip facing toward both contacts, and the middle part connected to the second link 21.
The base end is supported by the receiving part 24 of both links 1.
It is pivotally supported by a shaft 23 together with the other ends of 9 and 21. The link mechanism is designed so that this shaft 23 is always located on the side where both contact points are not present with respect to the line connecting the shafts 20 and 22. This insulator shielding plate 18 is
When the movable contact opens from the fixed contact, both links 1
9 and 21, it is inserted between both contacts, and is removed from between both contacts when closed.

(Operation) Figure 1 shows the closed state, and the shielding plate made of insulator 1
8 is removed from between both contacts, and the handle drive portion 11 maintains a balanced state.

If an overcurrent flows in this state, the symmetry of the handle drive unit 11 will be disrupted, and the movable contact plate 9 will operate and open, causing an arc between both the fixed and movable contacts. In this case, as shown in FIG. 2, the insulating shielding plate 18 is inserted between the main contacts 7a and 8a, and if an arc exists between the main contacts 7a and 8a, it is connected to the auxiliary contacts 7b and 8a. 8b and further extend the arc. As a result, the arc is stretched in a U-shape along the grid 16, and the arc currents are directed in opposite directions to each other as shown by the arrows, and the U-shape continues to widen due to electromagnetic repulsion, and is finally broken. It is.

(Effects) As described above, the present invention pivots one end of the first link to the intermediate part of the movable contact plate, and one end of the second link having a receiving part to the device stand, and the tip points toward both contacts. The proximal end of the insulating shield plate, whose intermediate part is supported by the receiving part of the second link, is pivoted together with the other ends of both links, so that when the movable contact is opened from the fixed contact, both Since an insulating shield plate is inserted between both contacts in response to the link, an arc extinguishing device is created that reliably transfers the arc to the auxiliary contact during opening, reducing wear and deterioration of the main contact. Moreover, since the insulating shielding plate is operated by a simple link mechanism, reliable operation can be guaranteed.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of one embodiment of the present invention, and FIG.
The figure is an explanatory diagram of the operation. 2... Instrument stand, 6... Terminal board, 7a... Main fixed contact, 7
b...Auxiliary fixed contact 7b, 8a...Main movable contact, 8b
... Auxiliary movable contact, 9... Movable contact plate, 11... Handle drive section, 15... Overcurrent detection element, 16... Grid, 17... Arc extinguishing device, 18... Insulator shielding plate, 1
9...First link, 21...Second link, 24...Second
Link receiver.

Claims (1)

[Claims] 1. When an overcurrent flows, the overcurrent operating element is activated to disrupt the symmetry of the handle drive part, and the movable contacts equipped on the movable contact plate are separated into main movable contacts and auxiliary movable contacts. It is a circuit breaker that is divided into a fixed contact and an auxiliary fixed contact and is opened from the fixed contact installed on the terminal board, and an arc extinguishing device consisting of a plurality of arc extinguishing grids is placed near both auxiliary contacts. In an arc extinguishing device for a circuit or disconnector installed, one end of the first link is pivoted to the middle part of the movable contact plate, one end of the second link having a receiving part is pivoted to the device stand, and the tip The proximal end of an insulating shielding plate, whose middle part is supported by the receiving part of the second link, is pivoted together with the other ends of both links so that the movable contact faces away from the fixed contact. An arc extinguishing device in a circuit or disconnector in which an insulating shield plate is inserted between both contacts in response to both links when the pole is opened.