WO2012006812A1

WO2012006812A1 - Miniature moulded case circuit breaker

Info

Publication number: WO2012006812A1
Application number: PCT/CN2010/077064
Authority: WO
Inventors: 南寅
Original assignee: 北京翠祥电器元件有限公司
Priority date: 2010-07-15
Filing date: 2010-09-17
Publication date: 2012-01-19
Also published as: CN102339694A; CN102339694B

Abstract

A miniature moulded case circuit breaker includes an insulating moulded case(9), inlet and outlet terminals (10,11) placed in the case, a thermal tripping system, a magnetic tripping system, a movable contact(16), a fixed contact, an operating mechanism (12) and an arc extinguishing system. The operating mechanism drives the movable contact to realize the closing and disconnecting of a circuit. The magnetic tripping system is composed of a magnetic yoke, cores (3,5), a sleeve and a coil (2). One end of the coil is connected with the fixed contact by the magnetic yoke or directly connected with the fixed contact and the other end of the coil is connected with the thermal tripping system or connected with the terminals. The coil of the magnetic tripping system is a non-circle structure. The cores of the magnetic tripping system are made of non-cylindrical magnetic material. The sleeve of the magnetic tripping system is a non-circle structure. The circuit breaker has the advantages of a thin type and simple structure.

Description

Small plastic case circuit breaker

The invention relates to a small plastic shell type circuit breaker, belonging to the field of low voltage electrical appliances.

Background technique

With the development of urban and rural power grids, the capacity of transmission and distribution systems continues to increase, and the degree of system integration continues to increase, which places higher demands on the performance of circuit breakers. At the same time, the number of circuits that need centralized control in the power grid is increasing. In order to facilitate management, the number of control loops in the unit space is maximized, that is, the space utilization rate of the protection appliances is increased. Only the volume of the protection appliances is reduced to increase the existing complete sets. The number of circuit breakers placed in the switchgear cabinet. At the same time, the miniaturization of the circuit breaker can save material and reduce manufacturing costs, and this problem is more prominent for a large number of small circuit breakers. Therefore, high-performance, miniaturized circuit breakers have become an inevitable trend in the development of electrical appliances. At present, the size of miniature circuit breakers widely used in the market is generally 18mm (two basic modules), but some products reduce the width of the circuit breaker at the expense of various technical performance indicators of the circuit breaker.

Summary of the invention

In view of the above problems, the present invention is directed to an ultra-thin small-sized plastic case circuit breaker which is simple in structure, high in reliability, and low in cost. It can reduce the width of the circuit breaker and improve the space utilization of the switch under the condition of protecting the original technical performance.

The technical solution adopted by the present invention is as follows:

The utility model relates to a small plastic shell type circuit breaker, which comprises an insulating plastic shell and an inlet and outlet terminal disposed therein, a thermal tripping system, a magnetic tripping system, a dynamic and static contact, an operating mechanism and an arc extinguishing system, and the operating mechanism drives the movable contact to realize The circuit is closed and disconnected; the magnetic trip system consists of a magnetic yoke, a core, a sleeve and a coil, one end of which is connected to the static contact via a magnetic yoke or directly to the stationary contact; the other end is connected to the thermal disconnector Connected or connected to a terminal, characterized by:

The coil of the magnetic trip system is a non-circular structure of at least one turn made of copper enameled wire.

The core of the magnetic trip system is made of a non-cylindrical magnetically permeable material.

The sleeve of the magnetic trip system is a non-circular structure.

The coil, the iron core and the sleeve in the magnetic tripping system all adopt a square structure.

The invention optimizes the components in the insulated plastic casing of the miniature circuit breaker, especially the magnetic tripping system, and the coil, the casing, the moving iron core and the static iron core in the magnetic tripping system adopt a square structure, compared with the traditional The circular structure, under the premise of having the same current-carrying density, that is, under the condition of having the same cross-sectional area, the square structure is smaller in width than the coil, the casing, the moving iron core, and the static iron core of the circular structure. Therefore, the magnetic tripping system can be placed inside the 9mm wide insulated housing under the condition of temperature rise. Compared with the traditional 18mm width product, the circuit breaker width is reduced by 50%, which has high operational reliability and simple structure. , low cost and other advantages.

DRAWINGS Figure 1 is an outline view of a small plastic case circuit breaker;

Figure 2 shows the internal structure of a small plastic case circuit breaker

Figure 3 is a simplified diagram of a magnetic tripping system for a small plastic case circuit breaker.

Detailed ways

The invention provides a 9mm wide and ultra-thin small plastic shell circuit breaker with simple structure, high reliability and low cost. In theory, miniaturization means that the size of the circuit breaker casing and its internal available space are significantly reduced. Therefore, miniaturization of the circuit breaker must require miniaturization of each component that constitutes the circuit breaker, including the arc extinguishing system. , contact system, operating mechanism, magnetic trip system, thermal trip system, etc. However, miniaturization is not simply a reduction in the size of components to meet the requirements. In the case of increasing power load, the premise of miniaturization is that the flow capacity of the electrical appliance cannot be sacrificed, which is accurately a unit volume flow. (including current carrying capacity and short-circuit breaking capacity), and even improved.

The main issues considered in the design of the present invention are as follows:

1. Flexibility and reliability of the organization's actions. Due to the reduction of the overall space, the operating mechanism should be optimized according to the size of the internal space of the circuit breaker housing, that is, under the requirements of the space structure, short circuit, overload fault and manual division and closing need to ensure the reliable operation of the operating mechanism ;

2. Temperature rise. The circuit breaker case is a closed space, which is easy to cause insufficient air flow and poor heat dissipation conditions. After the miniaturization design, the reduction of the shell volume reduces the heat dissipation area of the component, and the increase in component density leads to an increase in the heat per unit volume. These disadvantages are brought together so that the biggest difficulty in miniaturization design is temperature. l, so how to reduce the temperature rise needs to be considered in the miniaturization process.

According to GB10963. 1 temperature rise test and power consumption measurement requirements: At any suitable voltage, the current of each terminal of the circuit breaker is equal to In (the rated current of the circuit breaker), the temperature rise of the terminal connecting the external conductor should not Above 60K, the rated current should not exceed 13W per pole when the rated current is 63Α. The internal volume of the circuit breaker becomes smaller. The most important influence on the temperature rise is the magnetic tripping system. Generally speaking, in order to meet the temperature rise requirement in the national standard, the current carrying density Q of the coil in the magnetic tripping system should be less than 7A/mm ² , ie :

Q=I/S<7 ( 1 )

Where: Q is the current carrying density of the coil, A/mm ² ; I is the current flowing through the coil, A; S is the cross-sectional area of the coil, mm ² . The cross-sectional area of the coil is generally circular, and the moving and static cores also adopt a circular structure. However, due to the reduction of the internal space, under the condition that the level of the circuit breaker frame is not lowered, if the original structure is adopted, It is difficult to ensure that the temperature rise meets the requirements. In view of the above problems, the coil, the moving static core and the reaction spring of the small plastic case type circuit breaker magnetic tripping system of the present invention adopt a non-circular structure. The design of the invention absorbs the advanced design concepts at home and abroad, and optimizes the design and modular design of the overall structure of the circuit breaker, the shape of the components, the transmission mechanism, the closing spring and the like by means of the computer three-dimensional design software and the motion analysis software. The overall performance and mechanical characteristics of the circuit breaker are more fully guaranteed.

The invention comprises an insulating plastic outer casing and an inlet and outlet terminal disposed therein, a thermal tripping system, a magnetic tripping system, a dynamic and static contact, an operating mechanism and an arc extinguishing system, and the operating mechanism drives the movable contact to realize circuit closing and breaking; Trip system The magnetic coil, the iron core, the sleeve and the coil are composed of one end of the coil connected to the static contact via the magnetic pole or directly connected to the static contact; the other end is connected to the thermal stripper or connected to the terminal, wherein: the magnetic The coil of the trip system is a non-circular structure of at least one turn made of copper enameled wire. The core of the magnetic trip system is made of a non-cylindrical magnetically permeable material. The sleeve of the magnetic trip system is a non-circular structure.

The details will be described below with reference to the drawings.

Referring to the drawings, the 9mm wide and ultra-thin small plastic case circuit breaker provided by the present invention mainly comprises: a plastic insulating case and left and right terminals arranged therein, an operating mechanism, a magnetic trip system, a thermal trip system, and a static and dynamic contact System and arc extinguishing system. Wherein, the left terminal is connected to the magnetic trip system; the right terminal is connected to the thermal trip system; and the magnetic trip system and the thermal trip system are electrically connected by the dynamic and static contacts.

The base 9 which is one of the outer casings is the mounting and positioning reference for all internal parts. As shown in Fig. 1, the upper cover is covered with a width D of 9 mm. The left terminal 10 is the incoming end and is connected to the power supply; the right terminal 11 is the outgoing end and is connected to the load. The handle 12 is part of the operating mechanism and the operator can control the split of the circuit breaker by turning the handle.

The magnetic tripping system for short circuit protection mainly comprises a coil 2, a moving iron core 3, a jack 6 and the like. As shown in FIG. 3, one end of the coil 2 is electrically connected to the left connecting terminal 10, and the other end is electrically connected to the stationary contact 8. connection. When a short-circuit current occurs in the line, the magnetic field generated by the current flowing through the coil 2 causes the moving iron core 3 to move toward the static iron core 5, and the ram 6 that is integrally riveted with the moving iron core collides with the tripping mechanism, resulting in movement, The static contacts are separated and the circuit breaker is disconnected.

In the preferred embodiment, the coil, the sleeve, the moving iron core and the static iron core in the magnetic tripping system adopt a square structure, and have the same cross-sectional density, that is, the same cross-section, compared with the conventional circular structure. Under the condition of the area, the square structure is smaller in width than the coil, the sleeve, the moving iron core and the static iron core of the circular structure. Therefore, the magnetic trip system can be placed inside an insulating housing of 9 mm width while satisfying the temperature rise.

According to the actual structure and the size of the magnetic field, the iron core is 1. 5 mm thick steel plate or electric pure iron plate; the coil shape is 6. 5 mm X 18. 7 mm rectangle; two static iron cores are riveted together with the yoke; The iron core is assembled with the push rod formed by the cold pier and the reaction spring is placed inside the coil, and the initial position of the moving iron core is positioned by the base. Other parameters depend on the rated current rating of the circuit breaker and the size of the circuit breaker structure. As shown in Fig. 2, the thermal trip system for overload protection mainly includes a bimetal 13, a hard joint 14, an adjusting screw 15, and the like. One end of the bimetal 13 is electrically connected to the right terminal 11 by a hard connection, and the other end is electrically connected to the movable contact 16 by a soft connection. When the line is overloaded, the heat generated by the overload current causes the bimetal to bend and hit the trip device, causing the dynamic and static contacts to separate and the circuit breaker to open.

The size of the bimetal is primarily limited by the size of the product. The length of the shape is generally 30mn 40mm. In practical applications, the length of the electrification should be considered. It directly affects the deformation displacement of the bimetal and the magnitude of the thrust generated. The thickness of the bimetal has a great influence on the product. The thickness of the bimetal of the miniature circuit breaker Generally between 0. 5mn 1. 0mm; the width of the bimetal has little effect on product performance, generally between 4mm and 8mm. Assume that the current I is passed through the circuit. According to the bimetal displacement, the thrust calculation formula and the internal space of the circuit breaker, the width, length and thickness of the bimetal are respectively 5 33 mm, 0.77. : A = KL ² ·ΑΤ/Η (2)

F = KEbh ² ·ΑΤ/(4Σ) (3)

Where K is the specific bending of the bimetallic material; Ε is the elastic modulus; L is the length of the arm; b is the width, h is the thickness, F is the tripping force, ΔΤ is the temperature rise, and A is the bending displacement.

The key points of the technology of the present invention are:

1. The coil of the magnetic clutch system of the small plastic case circuit breaker is a non-circular structure of at least one turn made of copper enameled wire material;

2. The core of the magnetic clutch system of the small plastic case circuit breaker is made of a non-cylindrical magnetic material;

3. The sleeve of the small plastic case type circuit breaker magnetic trip system is a non-circular structure.

Claims

Claim

1. A small plastic case circuit breaker, comprising an insulating plastic case and an inlet and outlet terminal disposed therein, a thermal trip system, a magnetic trip system, a static and dynamic contact, an operating mechanism and an arc extinguishing system, and the operating mechanism drives the dynamic touch The head realizes the circuit to be closed and disconnected; the magnetic trip system consists of a magnetic yoke, a core, a sleeve and a coil, one end of which is connected to the static contact via a magnetic yoke or directly connected to the static contact; the other end is heated The trip system is connected or connected to the terminal, and is characterized by:

2. The small plastic case circuit breaker magnetic trip system of claim 1 wherein:

3. The small plastic case circuit breaker magnetic trip system of claim 1 wherein:

The sleeve of the magnetic trip system is a non-circular structure.

4. The small plastic case circuit breaker magnetic trip system of claim 1 wherein: