CN102427006A - Contact structure for low-current molded case low-voltage circuit breaker - Google Patents

Abstract

The invention discloses a contact structure for a low-current molded case low-voltage circuit breaker. A static conducting rod is positioned at the front-lower part of a movable contact; a static contact is positioned between the static conducting rod and the movable contact; a U-shaped lug boss of which the width is smaller than that of the static conducting rod is bent at the rearmost part of the static conducting rod in an extending manner facing to the opposite direction of current; the orientation of an opening of the U-shaped lug boss is opposite to the direction of the rearmost part current of the static conducting rod; a static contact is fixedly connected onto the U-shaped lug boss; the front end face of the U-shaped lug boss forwards extends at the same width to form a static arc striking sheet which is obliquely bent towards the direction of the movable contact and is abutted together; a distance is reserved between the static arc striking sheet and the static contact; U-shaped magnetism-increasing blocks are formed by eudipleurally upwards extending from the tail of the static conducting rod; four different functions of increasing the resistance of the circuit breaker, enhancing a self-excitation magnetic field in a contact region, absorbing an electric arc generated on the static contact during repelling open of the static contact and forming an electric repelling force between the movable contact and the static contact are achieved by one integral member; and the performance of the circuit breaker is increased.

Description

A contact structure for small current molded case low voltage circuit breaker

the

technical field

The invention relates to a small-current molded case circuit breaker, in particular to a contact structure of the small-current molded case circuit breaker, and belongs to the technical field of low-voltage electrics.

Background technique

Low-voltage circuit breakers are widely used. It is not only used for infrequent closing, opening, overload, short circuit, undervoltage and other fault protection of main lines, branch circuits, circuit terminals, etc., and electrical equipment, but also for various loads, such as Separate use and protection of lighting circuit, electric heating circuit, motor circuit, capacitor circuit, etc. The nature of the load is different, and the rated current and protection characteristics of the selected circuit breaker are also different. Therefore, according to the nature of the load and the protection function required by the load, molded case circuit breakers with small rated currents are also widely used at present. Mainly. In order to achieve the breaking index of the above-mentioned small current molded case circuit breaker, reduce the actual current flowing through the molded case circuit breaker when breaking, and protect the internal components of the molded case circuit breaker from being burned, the conductive circuit of the small current molded case circuit breaker The structure of some components needs to be adjusted to increase the loop resistance inside the molded case circuit breaker to achieve the purpose of current limiting.

At present, in the small current molded case circuit breaker, in order to increase the current limiting resistance of the small current molded case circuit breaker, the components of the conductive circuit are generally designed with three structures. The first structure is to make the static contact into a snake-like coiled shape, that is, a serpentine shape, so that the length from the connecting row to the static contact can be increased, thereby increasing the resistance of the static conductive rod to increase the circuit breaker Current limiting purpose. In this structure, in order to attract the arc generated on the static contact when the dynamic and static contacts are repelled, another static arc starter is made, and the other static arc starter is connected to the front end of the static contact in a certain way to realize Arc striking function. The second structure is that the connection bar and the static contact are split. In order to increase the resistance, the connection bar and the static contact will be connected together in a certain way through an S-shaped heating resistance alloy, thereby increasing the size of the circuit breaker. The resistance of the circuit breaker reduces the actual current flowing through the circuit breaker when it is broken, and protects the internal components of the circuit breaker from being burned. The third structure is to make the heating element inside the molded case circuit breaker into a snake-like structure or add a resistance element at the end of the heating element to increase the circuit resistance of the circuit breaker, so as to achieve the purpose of current limitation.

Among the above three structures, the first structure requires an additional static arc lead, and the static arc lead must be connected in a certain way. complex. When the arc is transferred to the static arc starter, because the current does not pass through the static contact but directly passes through the static arc starter at the front of the static contact, the current limiting resistance will be slightly reduced. The second structure needs to make three parts, and every two parts need to be connected in a certain way, and this structure can only achieve a simple function of increasing the current limiting resistance, and the number of parts increases, making the static The mounting of the contacts is complicated. In the third structure, the heating element is made into a serpentine structure to increase the resistance. Since the heating element is located in the tripping system of the molded case circuit breaker, in order not to affect the tripping performance of the circuit breaker, the resistance of the general heating element cannot be increased. , so the current limiting effect is not very obvious.

Contents of the invention

The purpose of the present invention is to improve the deficiencies of the prior art and provide a static contact structure of a small current molded case circuit breaker with simple structure, convenient installation and good current limiting effect, which can maximize the resistance when the circuit breaker is broken , reduce the actual current flowing through the circuit breaker when breaking, and protect the internal components of the circuit breaker from being burned.

The technical solution adopted by the present invention is: including static conductive rod, static contact and moving contact, the static conductive rod is located at the front and lower part of the moving contact, the static contact is between the static conductive rod and the moving contact, The most tail end of the end faces the opposite direction of the current and is bent with a U-shaped boss whose width is smaller than the static conductive rod. The opening of the U-shaped boss is opposite to the direction of the most tail current of the static conductive rod. On the U-shaped boss Fixedly connected to the static contact; on the front end surface of the U-shaped boss, extend to the front with the same width, a static arc leading piece bent towards the direction of the moving contact and combined together to form a static arc leading piece, the static leading arc piece and the static contact There is a distance between them.

Further, in the present invention, a U-shaped magnetizing block is symmetrically extended upward from the tail of the static conductive rod, and the static contact is located in the middle of the two U-shaped magnetizing blocks.

The beneficial effects of the present invention are:

1. The static conductive rod is made into a serpentine structure, and the ferromagnetic high-resistance alloy material is used to maximize the current-limiting resistance of the circuit breaker, reduce the actual current flowing through the circuit breaker when breaking the short-circuit current, and ensure that the circuit breaker Internal components are not burned.

2. The snake-shaped static conductive rod, U-shaped magnetization block and static arc-starting grid are made into an integrated structure, and an inverted U-shaped boss is arranged at the tail of the static conductive rod, which not only reduces the number of parts during installation , and four different functions can be realized through one part, namely (1) the serpentine structure can increase the resistance of the circuit breaker; (2) the U-shaped magnetic block can enhance the self-excited magnetic field in the contact area; (3) the static The arc striker can attract the arc generated on the static contact when the moving and static contacts are repelled; (4) The direction of the current flowing through the inverted U-shaped boss after power-on is opposite to the direction of the current flowing through the moving contact, so that it can The electric repulsion force is formed between the contacts. In the case of breaking the short-circuit current, the electric repulsion force will quickly pull the starting contact, so that the moving and static contacts will be separated quickly, so as to quickly extinguish the arc, thereby increasing the current limiting performance of the circuit breaker and making the circuit breaker performance is greatly improved.

3. The U-shaped magnetic block can enhance the self-excited magnetic field in the contact area, so that the dynamic and static contacts of the contact device of the molded case circuit breaker

The arc generated during repulsion is quickly transferred to the arc grid to avoid burning of the static contacts and more effectively ensure the breaking performance of the circuit breaker.

4. The U-shaped magnetic block is used in conjunction with the lower arc strike grid to protect the static contacts more effectively and ensure the breaking performance of the circuit breaker.

5. When the arc is transferred to the static arc grid, the structure can still ensure that the current flows through the serpentine structure, and because the static arc at the front of the static contact has a certain length, when the arc is transferred to the static After the arc grid is on, the resistance can be increased a little more.

Description of drawings

Further characteristics and advantages of the invention will become clear from the following description of a preferred but not exclusive embodiment, shown by way of non-limiting example in conjunction with the accompanying drawings.

Fig. 1 is an overall structural diagram of the present invention;

Figure 2 is an overall structural diagram of the static contact;

Fig. 3 is an exploded view of the static contact in Fig. 2 after expansion;

Fig. 4 is the top view of Fig. 2;

Fig. 5 is a schematic diagram of the current flowing through the static contact and the moving contact;

In the figure: 1. Static conductive rod; 2. Static contact; 3. Moving contact; 11. U-shaped magnetization block; 12. U-shaped boss; hole.

Detailed ways

     As shown in Figure 1, the present invention includes a static conductive rod 1, a static contact 2, and a moving contact 3, wherein the static conductive rod 1 is located at the front and lower side of the moving contact 3, and the static contact 2 is located between the static conductive rod 1 and the moving contact. Between the contacts 3 , the static contact structure includes a static conductive rod 1 and a static contact 2 .

As shown in Figure 2-5, the static conductive rod 1 is made into a snake-like structure, and the material of the static conductive rod 1 is a ferromagnetic high-resistance alloy. The serpentine structure can increase the length of the static conductive rod 1, and the ferromagnetic high-resistance alloy can increase the resistance of the static conductive rod 1, thereby increasing the current limiting resistance of the circuit breaker and reducing the actual current flowing through the circuit breaker when breaking. A U-shaped boss 12 with a width smaller than the static conductive rod 1 is bent at the end of the most tail end of the static conductive rod 1 facing the opposite direction of the current, and the opening of the U-shaped boss 12 faces the most tail current of the static conductive rod 1 The direction is opposite, that is, towards the front end of the static conduction rod 1, there is a certain height between the U-shaped boss 12 and the static conduction rod 1, so that the static conduction rod 1 and the U-shaped boss 12 are an integral structure, when a small current After the molded case circuit breaker is energized, the current flowing through the U-shaped boss 12 is in the opposite direction to the current flowing through the moving contact 3, as shown by the arrow in Figure 5, so that an electric repulsion force is formed between the moving and static contacts, and the short circuit is broken. In the case of current, the electric repulsion will quickly pull the starting contact 3, so that the moving and static contacts will be separated quickly, so as to quickly extinguish the arc, thereby increasing the current limiting performance of the circuit breaker. A round hole 122 for installing the static contact 2 is provided on the U-shaped boss 12 , and the round hole 122 is symmetrical to the left and right sides of the U-shaped boss 12 . A cylinder 21 for matching with the round hole 122 is arranged below the static contact 2 . After the cylinder 21 is placed in the round hole 122, the U-shaped boss 12 and the static contact 2 can be reliably connected through a certain way of processing. In this way, when the circuit breaker is closed, the current flows from the static conductive rod 1 flows through the moving contact 3 after passing through the U-shaped boss 12 and the static contact 2.

On the front end surface of the U-shaped boss 12, extend toward the front end with the same width, and extend a static arc-leading piece 121 bent toward the direction of the moving contact 3 and folded together. 2 times. In this way, the static conductive rod 1, the U-shaped boss 12 and the static arc-leading piece 121 are an integral structure, and the structure of the static arc-leading piece 121 being divided into two pairs can ensure the thickness of the static arc-leading piece 121, Prevent the electric arc generated by the repelling of the moving and static contacts from burning the static arc striker 121, so that the re-generated arc will burn the static contact 2 and affect the performance of the circuit breaker after breaking. The distance between the static arc striker 121 and the static contact 2 should be appropriate, otherwise the static arc striker 121 cannot play the role of arc strike. After the arc is transferred to the static arc runner 121, since the structure is an integral structure, it can be guaranteed that the current flows through the serpentine structure. Since the static arc striker 121 at the front end of the static contact 2 is integrated with the static conductive rod 1 and has a certain length, after the arc is transferred to the static arc striker 121, the current limiting resistance of the circuit breaker can still Add some more to reduce the actual current flowing through the small current molded case circuit breaker when breaking.

A U-shaped magnetizing block 11 is symmetrically extended upwards at the tail portion of the static conducting rod 1, so that the static conducting rod 1 and the U-shaped magnetizing block 11 are also integrated into an integrated structure. In this way, the static conducting rod 1 and the U-shaped boss 12 , static arc leading piece 121 and U-type magnetization block 11 four are an integral structure, and static contact is positioned at the middle position of U-type magnetization block 11. The height of the U-shaped magnetizing block 11 is higher than that of the U-shaped boss 12 . The U-shaped magnetizing block 11 can enhance the self-excited magnetic field in the static contact area, so that the arc generated when the dynamic and static contacts of the molded case circuit breaker contact device are repelled is quickly transferred to the static arc leading piece 121, avoiding static The burning loss of the contact 2 can more effectively guarantee the breaking performance of the circuit breaker.

The U-shaped magnetizing block 11 is used in conjunction with the static arc-leading piece 121, so that the static contact 2 has been well protected. If there is only the static arc-leading piece 121 alone, when the moving and static contacts are repelled to generate an arc, due to the contact The electric power in the area is not strong enough to quickly transfer the arc to the static arc striker 121, resulting in serious burning of the static contact 2 and greatly reducing the breaking performance of the circuit breaker. If only the U-shaped magnetizer 11 is used alone, Then when the moving and static contacts are separated to generate an arc, since there is nothing in front of the static contact that can transfer the arc, the arc will still burn on the static contact 2, resulting in serious burning of the static contact 2 and affecting the breaking of the circuit breaker performance. Therefore, only when the static arc striking piece 121 is used in conjunction with the U-shaped magnetizing block 11 can effective arc striking be achieved, the static contact 2 can be more favorably protected, and the breaking performance of the circuit breaker can be ensured.

An inverted U-shaped boss 12 is set on the static conductive rod 1. When the small current molded case circuit breaker is energized, the current flowing through the inverted U-shaped boss 12 is opposite to the direction of the current flowing through the moving contact 3, as shown in Figure 5 As shown by the arrow, this can increase the electrodynamic repulsion between the moving and static contacts, thereby also increasing the current limiting resistance of the small current molded case circuit breaker.

It can be seen that the static contact in the present invention is an integral structure formed by the static conductive rod 1, the U-shaped boss 12, the static arc-leading plate 121 and the U-shaped magnetizing block 11. The static conductive rod 1 is a snake. The U-shaped structure can increase the resistance of the circuit breaker, and an inverted U-shaped boss 12 is arranged at the tail of the static conductive rod 1. After power-on, the current flowing through the U-shaped boss 12 is opposite to the direction of the current flowing through the moving contact 3. An electric repulsion force is formed between the moving and static contacts. In the case of breaking the short-circuit current, the electric repulsion will quickly pull the starting contact, so that the moving and static contacts will be separated quickly, thereby quickly extinguishing the arc, thereby increasing the current limiting performance of the circuit breaker. In the invention, one part can realize four different functions at the same time, the structure is simple, and the performance is excellent, so that the breaking performance of the circuit breaker is greatly improved. The static contact is easy to install, and one part can realize four different functions of increasing the current limiting resistance and attracting the arc generated on the static contact when the moving and static contacts are repelled, enhancing the self-excitation magnetic field in the contact area, and increasing the electric repulsion. The performance of the circuit breaker is greatly improved.

Claims (3)

1. A contact structure for small current molded case low-voltage circuit breakers, including a static conductive rod (1), a static contact (2) and a moving contact (3), the static conductive rod (1) is located on the moving contact (3), the static contact (2) is between the static conductive rod (1) and the movable contact (3), and its characteristic is that the most tail end of the static conductive rod (1) faces the opposite direction of the current Extended bending has a U-shaped boss (12) whose width is smaller than that of the static conductive rod (1). The opening direction of the U-shaped boss (12) is opposite to the direction of the most tail current of the static conductive rod (1). The static contact (2) is fixedly connected to the U-shaped boss (12); on the front end face of the U-shaped boss (12), it extends toward the front with the same width and bends toward the moving contact (3) and fits on the The static arc runner (121) formed together has a distance between the static arc runner (121) and the static contact (2). 2. A contact structure for a small current molded case low-voltage circuit breaker according to claim 1 , characterized in that: a U-shaped magnetizing block ( 11), the static contact (2) is located in the middle of the two U-shaped magnetization blocks (11). 3. A contact structure for a small current molded case low-voltage circuit breaker according to claim 1 , characterized in that: a cylinder (21) is arranged below the static contact (2), and the static contact (2) and The round holes (122) on the cylinder (21) and the U-shaped bosses (12) are fixedly matched between the U-shaped bosses (12).

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