JPS607031A - Breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a circuit breaker, and particularly to a circuit breaker configured to operate instantaneously in the event of a short circuit and large current.

[Prior art]

Generally, a circuit breaker has a tripping mechanism that detects an overcurrent and automatically opens a movable contact.

Conventionally, in this type of circuit breaker, the time required from when an overcurrent flows through the tripping element and the tripping mechanism starts operating until the movable contact opens is relatively long due to mechanical limitations. Therefore, the circuit cannot be instantaneously interrupted, resulting in welding of contacts or burnout of current-carrying parts, making it difficult to obtain high breaking capacity. In addition, in circuit breakers that generate electromagnetic repulsion between the fixed and movable contacts to open the movable contacts in the event of a short circuit and large current, and utilize the electromagnetic repulsion that acts between the surface contacts, the electromagnetic repulsion Near the lowest operating current value that causes
The movable and fixed contacts melt due to the occurrence of a large current arc.
It will be damaged. Furthermore, the generated arc acts as a resistance component, reducing the circuit current, and as a result, both contacts come into contact, but there is a high risk that the melted contacts will weld together. In such a circuit breaker, the minimum operating current value is relatively high, so in the event of an intermediate overcurrent fault, it is difficult to coordinate with the tripping characteristics of the overcurrent tripping mechanism, and the overcurrent tripping mechanism There is a drawback that the instantaneous cut-off operation cannot be completed and ends in a half-finished operation, resulting in damage as described above.

[Purpose of the invention]

The present invention eliminates such conventional drawbacks and consists of a movable contact support whose movable contact side is rotated by an automatic tripping mechanism, and a movable contact rotatably provided on this support. In addition, a set of engagement pieces is provided on the movable contact and its support, so that normal breaking operation is performed in the event of an overcurrent, and in the event of a short circuit and large current, only the movable contact is interrupted by the electromagnetic repulsive force that acts between the surface contacts. The purpose of this is to momentarily slightly open the movable contact and at the same time completely open the movable contact using an automatic tripping mechanism, thereby significantly increasing the breaking capacity without welding the contacts or damaging the current-carrying parts. be.

[Structure of the invention]

The circuit breaker according to the present invention is a circuit breaker having an overcurrent tripping mechanism, and includes a movable contact support whose base end is rotatably pivoted to a base; a movable contact whose proximal end is pivotably mounted; a movable engagement piece that surrounds the movable contact in a U-shape; a movable engagement piece that is attached to the movable contact support and faces and cooperates with the movable engagement piece; a fixed piece, a U-shaped fixed contact provided opposite to the movable contact, and a fixed contact that moves the movable contact around a mounting shaft provided at the tip of the movable contact support toward the fixed contact. energize,
and a single or a plurality of contact springs that bias the movable contact support body around the mounting axis in a direction in which the movable contact support is disengaged from the fixed contact, and an engagement provided between the movable engagement piece and the fixed piece. A device that biases the movable engagement piece toward the fixed side; and the engagement device that operates automatically or manually at or just before the maximum disengagement position of the movable contact during a tripping operation. The present invention is characterized by comprising an unlocking device, a movable contact actuating mechanism, and a connecting mechanism that connects the tripping mechanism and the movable contact support. [Embodiment] Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

A terminal seat 2 formed on a case body 1 made of an insulating material is provided with space for three fixed contacts formed in a U-shape. A movable contact 4 is rotatably pivoted to a mounting shaft 6 formed on the support 5 b). The movable contact 4 has a mounting shaft 7 provided thereon; a movable engagement piece 8 (see FIG. 5) pivotably mounted thereon; to be located; to be installed. In addition, the movable contact 4
The support body 5 is rotatably pivoted to a mounting shaft 9 formed on a base, for example, the case body 1, and a fixed piece 10 that cooperates with the movable engagement piece 8 is attached to this. There is. This movable contact support 5 and an external operation handle (not shown)
The actuating mechanism and the tripping mechanism are connected by a drive shaft 21, and the connection mechanism by the drive shaft 21 is used to perform the closing and tripping operations of the contact. The mounting shaft 9 has a structure in which the movable contact 4 is urged toward the fixed contact 3 around a mounting shaft 6 provided at the tip of the movable contact support 5, and the movable contact support 5 is A contact spring 11 is mounted around the mounting shaft 9 and urges the fixed contact 3 in a direction to be disengaged.

Although the contact spring 11 is formed of a single spring material, it is not limited to a single spring material; It is also possible to use a separate spring for biasing the child support 5 in the dissociation direction from the fixed contact 3, and to make a plurality of springs work together. In addition, the case body 1 includes a tripping element 12 (for example, consisting of an electromagnetic large tripping coil with a time-limiting element) that detects abnormal currents such as overcurrents and short-circuit currents and operates a tripping mechanism (not shown). is set up.

Reference numeral 13 denotes the movable iron piece, which is configured to be attracted to the tripping element 12 at an appropriate time when an abnormal current occurs, thereby driving the drive shaft 14 of the tripping mechanism to detach the latching mechanism. Reference numeral 15 denotes a terminal on the load side, which is fixed to a terminal seat 16 formed in the case body 1, and is connected to one end 17 of the excitation winding of the decoupling element 12. Reference numeral 18 denotes a conducting wire connecting the movable contactor 4 and the other end of the excitation winding of the tripping element 12, and a flexible copper stranded wire or the like is used so as not to prevent the movement of the movable contactor 4. Note that an engagement device is provided between the movable engagement piece 8 and the fixed piece 10. That is, the fixed piece 10
As shown in FIG. 6, an engaging tooth 10a is formed on the movable engaging piece 8, and the movable engaging piece 8 is configured to mesh with an engaging groove 8b formed in the engaging groove 8b during a locking operation and be locked. There is. Further, a suppression spring 19 is mounted between the movable engagement piece 8 and the movable contact 4 so that the movable engagement piece 8 is always on the fixed piece 10 side.

Furthermore, a stopper 20 is attached to the case body 1 so that when the movable contact 4 is separated to a certain position, it comes into contact with the tip 8c of the movable engagement piece 8 and unlocks the lock with the fixed piece 10.

The operation of the circuit breaker according to the present invention having such a configuration will be described below.

First, the tripping cutoff operation by manual operation will be explained with reference to FIG. 2. When an external operation handle is operated in the cutoff direction when an overcurrent occurs, the movable contact support 5 is rotated in the opening direction to a predetermined position by the drive shaft 21, whereby the movable contact 4 is separated from the fixed contact 3. to cut off the electrical circuit. The separation distance G1 between the fixed and movable contacts at this time is set to an appropriate value required for a general circuit breaker. Further, the contact spring [1] is cut into the support 5 and acts as a repulsion spring.

Next, the interrupting operation when a large current such as a short circuit current flows will be explained with reference to FIGS. 3 and 4.

In this case, a large current flows between the movable engagement piece 8 attached to the movable contact 4 and the fixed piece 10 fixed to the movable contact support 5, causing electromagnetic repulsion, which causes the movable The engaging piece 8 momentarily rotates in the direction of the fixed piece 10. In this case, the contact spring 11 acts as a repulsion spring against the rotation of the movable contact 5.Therefore, as shown in FIG. 3, only the movable contact 4 is rapidly separated from the fixed contact 2, thereby performing a primary interruption. At this time, the engagement groove 8b of the movable engagement piece 8 is pressed against the engagement tooth 1 of the fixed piece 10 by the action of the suppression spring 19.
0a and is locked, thereby preventing the movable contact 4 from returning and maintaining the separation distance G2 from the fixed contact 3.

On the other hand, a large short-circuit current flows through the tripping element 12, which causes the tripping mechanism to operate with a slight delay determined from the mechanism and drive the movable contact support 5 in the opening direction. At this time, since the movable contact 4 is locked to its support 5 via the movable engagement piece 8 and the fixed piece 10 during the above-mentioned disconnection, the movable contact 4 is further opened as shown in FIG. A secondary cut-off is then performed. If there is no stopper 20, the maximum separation distance G3 between the fixed and movable contacts will be G1+G2 as shown in FIG. When they come into contact, the lock is unlocked and held in the tripped state shown in FIG. That is, the engagement groove 8b of the movable engagement piece 8 and the engagement tooth 10a of the fixed piece 10 are locked at the time of the primary cutoff by the pressing force of the stopper 20 just before the maximum separation point due to the secondary cutoff.
is unlocked, and as shown in FIG. 2, the movable contact 4 returns to a state in which its engaging portion 4a engages with the drive shaft 21 of the support body 5 due to the action of the contact spring 11, and the separation distance G1 hold.

Generally, the current value at which contacts tend to weld is, for example, 50
In an ampere frame circuit breaker, since the current is about 1500A to 2500A for silver oxide cadmium contacts and 2500A to 5000A for silver tungsten contacts, the electromagnetic repulsion generated in the fixed and movable solid contacts 3 and 4 causes the movable and fixed The minimum operating current value for the locking operation of the image engaging pieces 8 and 10 is set to be less than the current value that tends to cause welding, for example 20
If the OA is suppressed to approximately 0OA, welding of the contacts will not occur under any conditions. The circuit breaker according to the present invention is capable of primary breaking at a sufficiently low current value compared to the current value that tends to cause welding, and can fully satisfy the above conditions. i.e. 50
In an ampere frame circuit breaker, no matter which contact material is used, as long as there is an electromagnetic repulsion of about 500 to 800 g, there will be no problem even if the welding current is applied. Repulsion force is 1.5k
It has been confirmed that the tripping cut-off operation can be performed without any problem.

It should be noted that the circuit breaker according to the present invention is not limited to the embodiments described above; for example, in order to unlock the movable contact that is locked at the time of the second shutdown, the circuit breaker according to the present invention may be automatically activated by the stopper at the time of the second shutdown described above. Instead, a return device may be provided separately and the lock may be manually unlocked after the shutoff is completed, or the locking device may be separately provided between the movable contact and the support by various means, etc. Various optional changes may be made. is possible.

FIGS. 7 and 8 show another embodiment of the present invention, whose structure and operation are similar to those described above, but differ in the following points. That is, the end 4b of the movable contactor 4 that engages with the contact spring l'l is formed into a circular arc shape.

When the movable contact 4 is driven relative to the movable contact support 5 and rotated around the mounting shaft 6 when an overcurrent occurs, the contact spring is prevented from being pushed down and its elastic force is prevented from increasing. This allows the movable contact 4 to be smoothly moved relative to each other.

〔Effect of the invention〕

As described above, according to the present invention, when a short circuit generates a large current, the electromagnetic force instantly performs the primary interruption, and then the tripping mechanism immediately performs the secondary interruption, so the passage time of the short circuit current is extremely short. Therefore, there is no damage to the current-carrying part, and the electromagnetic repulsion force acts before the short-circuit current reaches its maximum value, resulting in a so-called current-limiting effect in which primary cutoff is initiated.

In addition, at the time of secondary shutoff, only the lightweight movable contact opens and closes independently of its support, making it possible to instantaneously and reliably shut off the contact, and furthermore, sufficient tripping distance can be obtained through secondary shutoff. In combination with the above-mentioned effects, the breaking capacity is significantly increased. Furthermore, since the locking operation by the fixed and movable surface engaging pieces is performed sensitively at a sufficiently low current value,
It has various excellent advantages, such as being able to completely prevent contact welding by suppressing the minimum operating current value below the current value that causes contact welding.

[Brief explanation of drawings]

Fig. 1 is a front cutaway sectional view showing an embodiment of the present invention, Fig. 2 is a front view of main parts showing the same embodiment in a tripping state, and Fig. 3 is a main part front view showing the same embodiment in a primary cut-off state. Figure 4 is a front view of the main part showing the secondary blocking state, Figure 5 is a front and side view of the movable engagement piece, Figure 6 is a top and front view of the fixed piece, and Figure 7 is a front view of the main part. A front cutaway view showing another embodiment of the invention,
FIG. 8 is a front view of essential parts showing the same embodiment in a tripped state. 3: Fixed contact, 4: Movable contact, 5: Movable contact support, 8: Movable engagement piece, 10: Fixed piece. 11: Contact spring, 12: Tripping element, 19: Pressing spring,
20 Nystopper. Figure 1 Kaya 2 Figure 5 Figure 6 Procedural amendment 8 (voluntary) 1. Indication of the case Patent Application No. 112379 of 1982 2 Name of the invention Circuit breaker 3 Specification of the person making the amendment 5 Contents of the amendment (1) Item 5 in the "Detailed Description of the Invention" column in the specification page 8
The line "[Example]" is deleted, and "[Example]" is added between the eighth and ninth lines.

Claims (1)

[Claims] 1. In a circuit breaker having an overcurrent release mechanism, a movable contact support whose base end is rotatably pivoted to a base, and a base end rotatably pivoted to the tip of the movable contact support. a movable contact mounted on the movable contact, a movable engagement piece surrounding the movable contact in a U-shape, a fixed piece attached to the movable contact support and opposing and cooperating with the movable engagement piece, and the movable contact. a U-shaped fixed contact provided facing the child; the movable contact is urged toward the fixed contact around a mounting shaft provided at the tip of the movable contact support; a single or a plurality of contact springs that bias the movable contact support body around the mounting axis in a direction in which it is disengaged from the fixed contact; an engagement device provided between the movable engagement piece and the fixed piece; a spring that biases the movable engagement piece toward the fixed side, and an unlocking of the engagement device that is activated automatically or manually at or immediately before the maximum disengagement position of the movable contact during a tripping operation; What is claimed is: 1. A circuit breaker comprising: a movable contact actuating mechanism; and a connecting mechanism connecting the tripping mechanism and a movable contact support.