JPH01298622A - Circuit breaker - Google Patents

Abstract

PURPOSE:To shorten a time required for commutation so as to attempt protection of elements by connecting an overcurrent detecting element and a shortcircuit current detecting element to the fixed contact of a circuit breaker and to a movable contact respectively and installing the commutation part of an arc running plate in the vicinity of the fixed contact. CONSTITUTION:When shortcircuit current or over current flows with contacts in the state of contact, a movable contactor 3 starts its separation and simultaneously an arc A is generated a fixed contact 1 and a movable contact 2. The arc A is prolonged by receiving driving power from an arc-extinguisher 6 and commutated in a commutation part 7 close to the contact 1. When the arc is commutated, an over current detecting unit 4 comes in its shortcircuited state. Further, when the movable contactor 3 is displaced to approach an arc running plate 8, arc A of the movable contact 2 is also commutated to the running plate 8 and a shortcircuit current detecting element 5 also comes in a shortcircuited state. Thus, and arc is commutated in a short time to enhance the protection of element.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a circuit breaker, and particularly to a circuit breaker in which protection of an overcurrent detection element is enhanced.

[Prior Art] This type of circuit breaker is generally shown schematically in Fig. 8, where 1 is a fixed contact, 2 is a movable contact, 3 is a movable contact, and 4 is an overcurrent contact. Detection element 5 is a short circuit current detection element, 6 is an arc extinguisher, 7 is an arc running plate on the fixed contact side connected to the fixed contact, 8 is an arc running plate on the movable contact side, and 9.9 is a terminal. That is, the redetection element 4.5 is
While being connected in series to the movable contactor 3, it is arranged in parallel to the arc traveling plate 8.

Therefore, when both contacts 1.2 are opened (separated) and an arc is generated, and the arc is commutated from the movable contact 2 to the arc travel plate 8, the re-detection elements 4 and 5 are short-circuited and protected. be done.

Further, Japanese Patent Laid-Open No. 59-66030 proposes a device in which arc is commutated in order to protect a semiconductor element for remote control.

[Problems to be Solved by the Invention] Although the overcurrent detection element 4 is protected in the above-mentioned device shown in FIG. 8, the so-called arc stagnation time until the arc commutates is still 1 to 1. It takes 5ms. Therefore, it is necessary to withstand passing energy of 1 to 1 and 5 ms.

Further, although the device disclosed in Japanese Patent Application Laid-open No. 59-66030 is effective in protecting the remote control semiconductor device, the protection for the overcurrent detection device is similar to that shown in FIG.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a circuit breaker that can further enhance the protection of an overcurrent detection element.

[Means for solving the problem] In order to solve the problem, the circuit breaker of the present invention has the following features:
It has a fixed contact and a movable contact that connects and separates from the fixed contact, and the movable contact operates so that the movable contact separates from the fixed contact when the symmetry is lost due to linkage, and when an overcurrent flows. In a circuit breaker that includes an overcurrent detection element that displaces and disrupts the symmetry of the link mechanism, and an arc extinguishing device that has a large number of laminated grid plates, the fixed contact and the overcurrent detection element are connected in series, and the fixed contact and the overcurrent detection element are connected in series. A commutation section that is parallel to the overcurrent detection element and that commutates the arc from the fixed contact when an arc occurs at the fixed and movable contacts is provided close to the fixed contact, and the commutation section is equipped with an arc extinguishing device. This configuration includes an arc traveling plate extending to a position facing the outer grid plate.

[Function] When both contacts open (separate) and an arc is generated, the commutation part of the arc traveling plate is provided close to the fixed contact, so the arc of the fixed contact will be commutated in an extremely short time. The overcurrent detection element becomes short-circuited and no current flows. Therefore, the protection of the overcurrent detection element is improved by the shorter time required for arc commutation.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

Reference numeral 1) is a stand, and reference numeral 12 is a cover, which together constitute the housing of the circuit breaker.

Reference numeral 1 denotes a fixed contact, which is provided on an L-shaped fixed contact plate 13 and fixed to the device stand 1).

A movable contact 2 is provided near the tip of a movable contact 3 curved into an arc so as to come into contact with and separate from the fixed contact 1. The movable contactor 3 is arranged vertically in the housing so that the proximal end is located in the cover 12 and the distal end is located in the device stand 1). ). Therefore, if both contacts 1.2 are in contact and the link mechanism is out of balance, the movable contact 2 will operate to separate from the fixed contact 1. 14 is a contact spring.

Reference numeral 4 denotes an overcurrent detection element such as a bimetal, which has a vertically elongated U-shape, and its base end is fixed to an arc traveling plate to be described later.

5 is a short-circuit current detection element such as a solenoid, and is disposed at a position where the plunger 5a can be linked with the movable contact 3 and the link mechanism. That is, one end of the plunger 5a is engaged with the middle part of the movable contact 3, and when a short circuit current flows through the short circuit current detection element 5, the plunger 5a moves to the left in the figure and moves the movable contact 3. Pull forcibly to separate both contacts 1.2. A braided wire 15 connects the short-circuit current detection element 5 and the movable contact 3 in series. On the other hand, the overcurrent detection element 4 has a pressing part 4a made of an insulating material at the tip corresponding to the end of the plunger 5a, and when an overcurrent flows, the pressing part 4a is thermally deformed and the pressing part 4a is attached to the plunger 5a. Pushing in one end, the other end of the plunger 5a disrupts the symmetry of the linkage and also forces the contacts 1.2 apart. A braided wire 16 connects the overcurrent detection element 4 and the fixed contact plate 13 in series.

Reference numeral 6 denotes an arc extinguishing device formed by laminating a large number of grid plates 6a, and the grid plates 6a are arranged parallel to the bottom of the table 1). A space S exists between the arc extinguishing device 6 and both contacts 1.degree.2, in which the arc is stretched and moved.

Reference numeral 7 denotes an arc traveling plate that constitutes the main part of the present invention.

The arc traveling plate 7 is bent and extended so that one end serves as a terminal portion 7a and the other end serves as a facing portion 7b facing the outer (lowermost end in this embodiment) grid i6a.
) is fixed. The part that connects the terminal part 7a and the facing part 7b is the commutation part 7C, and the part that is close to the fixed contact 1 is arranged so that the arc commutates from the fixed contact 1 when an arc occurs in the fixed and movable contacts 1.2. have Further, the base end of the overcurrent detection element 4 described above is fixed to the commutation part 7C or the terminal part 7a, and therefore the arc running plate 7 is in a parallel relationship with the fixed contact 1 and the overcurrent detection element 4. .

8 is an arc travel plate on the movable contact side. The rest of the structure is the same as that of a well-known circuit breaker, so a description thereof will be omitted.

Next, the operation will be explained with reference to FIGS. 4 to 6, which are schematically shown.

FIG. 4 shows the contact state. When a short circuit current or overcurrent flows in this state, the contacts begin to separate, and at the same time an arc A is generated between both contacts. This arc A is elongated by the driving force of the arc extinguishing device 6, and since the commutation section 7C of the arc running plate 7 is close to the fixed contact l, after several hundred microseconds, the arc A is elongated as shown in Fig. 5. The current is commutated from the fixed contact 1 to the commutation section 7C. When the arc A commutates in this manner, the overcurrent detection device 4 becomes short-circuited, and no current flows therethrough. When the movable contact 3 is further displaced and approaches the arc traveling plate 8, the arc A of the movable contact 2 (movable contact 3) also commutates to the arc traveling plate 8, as shown in FIG. It becomes a short-circuited state.

FIG. 7 compares the actual device A1 and the conventional device A2 with respect to the current flowing through the overcurrent detection element, with time on the horizontal axis and current value on the vertical axis. In addition, BL is a breaking current, SL is a short circuit current, and AV is an arc voltage.

[Effects of the Invention] Since the circuit breaker of the present invention is configured as described above, when both contacts are opened (separated) and an arc is generated, the commutation portion of the arc running plate is close to the fixed contact. Due to this arrangement, the arc of the fixed contact commutates in an extremely short time, and the overcurrent detection element becomes short-circuited and no current flows. Therefore, the time required for the arc commutation is shortened.
The protection of the overcurrent detection element is enhanced.

[Brief explanation of the drawing]

Fig. 1 is a partial sectional view showing an embodiment of the present invention, Fig. 2 is an exploded perspective view of the vicinity of the fixed contact, Fig. 3 is a perspective view of the arc running plate, and Fig. 4 is the contact contact Fig. 5 is a schematic diagram of the state immediately after the contact separation, Fig. 6 is a schematic diagram of the state before the completion of the contact separation operation, Fig. 7 is a comparative characteristic diagram of the current value, and Fig. 8 is a schematic diagram of the state immediately after the contact separation. , a schematic diagram of a conventional example. 1-Fixed contact, 2-Movable contact, 3-Movable contact, 4-Overcurrent detection element, 5-Short circuit current detection element, 6-
Arc extinguishing device, 7-・Arc running plate, 7c・-Commuting part, 8-
Arc traveling plate on the movable contact side, terminal 9.

Claims (1)

[Claims] (1) A movable contact that has a fixed contact and a movable contact that connects and separates from the fixed contact, and that is linked to a link mechanism and operates so that the movable contact separates from the fixed contact when the symmetry is disrupted, and the movable contact operates to separate from the fixed contact. In a circuit breaker that includes an overcurrent detection element that displaces when current flows and disrupts the symmetry of the link mechanism, and an arc extinguishing device consisting of a number of laminated grid plates, the fixed contact and the overcurrent detection element are connected in series, and this A commutation section that is parallel to the fixed contact and the overcurrent detection element and that commutates the arc from the fixed contact when an arc occurs in the fixed and movable contacts is provided close to the fixed contact, and the commutation section is A circuit breaker characterized by being provided with an arc traveling plate extending to a position facing an outer grid plate of an arc extinguishing device.