WO2017173813A1

WO2017173813A1 - Thermal tripping apparatus for moulded case circuit breaker

Info

Publication number: WO2017173813A1
Application number: PCT/CN2016/103080
Authority: WO
Inventors: 黎佳财; 高仁旦; 叶文杰; 江华华
Original assignee: 浙江正泰电器股份有限公司
Priority date: 2016-04-05
Filing date: 2016-10-24
Publication date: 2017-10-12
Also published as: CN205657029U

Abstract

A thermal tripping apparatus for a moulded case circuit breaker comprises a conductive plate (1), an iron core (2) and a bimetallic strip (3), wherein the iron core (2) is a circular iron core structure provided with a through hole (20), the conductive plate (1) runs through the through hole (20) of the iron core (2), and the bimetallic strip (3) is mounted on the iron core (2) and is not in contact with and not connected to the conductive plate (1). The thermal tripping apparatus for a moulded case circuit breaker realizes an energy transfer between the conductive plate (1) and the bimetallic strip (3) using an inductive heating principle of the magnetic conductive iron core (2) in an alternating magnetic field, thereby guaranteeing that the circuit breaker can break a circuit in time when an overload phenomenon occurs. The thermal tripping apparatus for a moulded case circuit breaker is simple in structure and safe, avoids the instability and lack of safety of energy transfer by directly connecting the conductive plate (1) and the bimetallic strip (3), and improves the reliability and safety of a tripping motion of the circuit breaker, and has a wide application range.

Description

Thermal trip device for molded case circuit breaker

Technical field

The utility model relates to the field of low-voltage electrical appliances, in particular to a thermal tripping device for a molded case circuit breaker.

Background technique

In the thermal tripping device of the existing molded case circuit breaker, the bimetal piece is directly connected to the conductive plate. When the current is overloaded, the bimetal piece and the conductive plate will heat up correspondingly, and the bimetal piece is bent and deformed by the generated thermal power. The traction rod is driven to complete the tripping action, and such a connection method is not suitable for a large current such as a 1600A molded case circuit breaker, which will cause problems such as instability and insecurity. In addition, the existing molded case circuit breakers have two characteristics that cannot balance the low temperature rise and the fast trip, resulting in poor performance and reliability of the circuit breaker.

Utility model content

The purpose of the utility model is to overcome the defects of the prior art and provide a reliable and safe thermal release device for a molded case circuit breaker.

In order to achieve the above object, the utility model adopts the following technical solutions:

A thermal trip device for a molded case circuit breaker, comprising a conductive plate 1, a core 2 and a bimetal 3, the core 2 being an annular core structure provided with a through hole 20, the conductive plate 1 running through The through hole 20 of the iron core 2 is mounted on the iron core 2 and is not in contact with the conductive plate 1.

Preferably, the conductive plate 1 includes a first conductive plate 11 and a second conductive plate 12 which are sequentially connected in a current direction, and the second conductive plate 12 of the conductive plate 1 extends into the through hole 20 of the iron core 2, wherein The width of the through hole 20 of the iron core 2 is larger than the width of the second conductive plate 12 and smaller than the width of the first conductive plate 11.

Preferably, the iron core 2 is provided with a thermal element 23, and the bimetal 3 is connected to the thermal element 23, and the specific heat capacity of the thermal element 23 is smaller than the specific heat capacity of the iron core 2.

Preferably, the iron core 2 includes a U-shaped iron core 211 and a strip-shaped iron core 212 disposed on the open end of the U-shaped iron core 211, and both ends of the strip-shaped iron core 212 are overlapped by the first screw 213 The arms are fixed to both sides of the U-shaped core 211 to form the annular core structure provided with the through holes 20.

Preferably, the strip core 212 is mounted with the bimetal 3, and the strip core 212 and the double The heat element 23 is disposed between the metal sheets 3, and the heat element 23 is a square ring structure matched with the strip core 212, and is matched and fitted on the strip core 212; the second screw 22 is a bimetal 3. The heat element 23 and the strip core 212 are fixed together.

Preferably, the bimetal 3 includes a first metal piece 31 and a second metal piece 32 connected in an L shape, wherein the first metal piece 31 extends into the through hole 20 of the core 2 and passes through the second screw 22 It is fixed to the inner side wall of the iron core 2.

Preferably, one end of the second metal piece 32 is connected to the first metal piece 31, and the other end of the second metal piece 32 is mounted with an adjusting bolt 4 for adjusting the end of the adjusting bolt 4 and the thermal trip device. The distance between the drawbars 5.

Preferably, the bimetal 3 is a straight strip-like structure, and one end of the bimetal 3 is directly welded and fixed to the core 2.

Preferably, the ratio of the width of the first conductive plate 11 to the width of the second conductive plate 12 is 9:7; the ratio of the width of the first conductive plate 11 to the width of the through hole 20 is 5:4.

Preferably, the width of the through hole 20 is 36 mm, and the width of the portion of the conductive plate 1 penetrating the through hole 20 is 35 mm * 15 mm.

The thermal trip device of the molded case circuit breaker of the present invention can realize the energy transfer between the conductive plate and the bimetal by using the induction magnet core in the alternating magnetic field induction heating principle, thereby ensuring that the circuit breaker can be overloaded Timely breaking, the structure is simple and safe, avoiding the instability and unsafeness of the direct connection of the conductive plate and the bimetal, and improving the reliability and safety of the tripping action of the circuit breaker, and the application range is wide. In addition, the structure of the conductive plate is such that the width of the two ends of the conductive plate along the current direction is large to small, which is convenient for rapid flow guiding, reducing the current carrying capacity per unit area, avoiding high temperature rise of the product, and facilitating current aggregation to induce magnetic field change transmission. The core is ironed, so that the iron core is quickly heated to drive the bimetal to bend to complete the tripping action, thereby improving the sensitivity and reliability of the tripping action.

DRAWINGS

1 is a schematic overall view of a thermal trip device of a molded case circuit breaker of the present invention;

2 is a partial schematic view of a thermal trip device of a molded case circuit breaker of the present invention;

3 is a schematic structural view of a conductive plate of the present invention;

4 is an assembled view of the iron core and the bimetal of the present invention.

detailed description

The specific embodiment of the thermal trip device of the molded case circuit breaker of the present invention will be further described below with reference to the embodiments given in FIGS. 1 to 4. The thermal trip device of the molded case circuit breaker of the present invention is not limited to the description of the following embodiments.

As shown in FIG. 1 and FIG. 2, the thermal trip device of the molded case circuit breaker of the present invention comprises a conductive plate 1, a core 2 and a bimetal 3, and the core 2 is a ring-shaped iron provided with a through hole 20. In the core structure, the conductive plate 1 penetrates the through hole 20 of the iron core 2, and the bimetal 3 is mounted on the iron core 2 and is not in contact with the conductive plate 1. The induction heating of the iron core 2 is transmitted to the bimetal 3, so that the bimetal 3 is thermally deformed and bent, thereby driving the drawbar 5 of the thermal trip device to rotate to complete the tripping action. The energy transfer between the conductive plate and the bimetal is realized by using the principle of induction heating of the magnetic core in the alternating magnetic field, which is manifested by the large alternating current on the conductive plate generating a strong magnetic field, so that the surface of the magnetic core in the magnetic field is formed. Inductive current, the iron core relies on the internal resistance of its own material to achieve rapid heating, and then transfer heat to the bimetal, which can ensure that the circuit breaker can be broken in time when the overload occurs, the structure is simple and safe, avoiding the conductive plate and the double The direct connection of the metal piece transfers the unstable and unsafe energy, improves the reliability and safety of the tripping action of the circuit breaker, and has a wide application range.

As shown in FIG. 3, the conductive plate 1 of the present invention is an integrally formed structure including a first conductive plate 11 and a second conductive plate 12 which are sequentially connected in a current direction, and the conductive plate 1 extends into the iron core through the second conductive plate 12. The through hole 20 of 2 realizes electromagnetic induction with the iron core 2, wherein the width of the through hole 20 of the iron core 2 is larger than the width of the second conductive plate 12 and smaller than the width of the first conductive plate 11. The structure of the conductive plate is such that the width of the two ends of the conductive plate along the current direction is large to small, which is convenient for rapid flow guiding, reduces the current carrying capacity per unit area, avoids high temperature rise of the product, and facilitates current concentration to cause magnetic field change to be transmitted to the iron. The core enables the iron core to rapidly heat and drive the bimetal to bend to complete the tripping action, thereby improving the sensitivity and reliability of the tripping action. Further, the ratio of the width of the first conductive plate 11 to the width of the second conductive plate 12 is 9:7; the ratio of the width of the first conductive plate 11 to the width of the through hole 20 is 5:4. Specifically, the width × thickness of the first conductive plate 11 is 45 mm * 15 mm, the width × thickness of the second conductive plate 12 is 35 mm * 15 mm, and the width of the through hole 20 is 36 mm. Two characteristics of low temperature rise and fast trip of the optimal balanced circuit breaker are achieved.

As shown in FIG. 2 and FIG. 4, the iron core 2 of the present invention is provided with a heat element 23, and the bimetal 3 is connected to the heat element 23, and the specific heat capacity of the heat element 23 is smaller than the specific heat capacity of the iron core 2. Thermal components can be used Made of copper material, the specific heat capacity of copper is less than iron, that is, when the same heat is absorbed, the temperature of copper is higher than that of iron. The heat element acts to transfer the heat generated by the induction heating of the iron core to the bimetal more effectively, which is beneficial to the bending of the bimetal and the tripping action of the circuit breaker is more reliable. Specifically, the iron core 2 includes a U-shaped iron core 211 and a strip-shaped iron core 212 disposed on the open end of the U-shaped iron core 211. Both ends of the strip-shaped iron core 212 are overlapped and fixed in the U shape by the first screw 213. The arms on both sides of the iron core 211 are formed to form the annular core structure provided with the through holes 20. The detachable assembled square toroidal core structure facilitates assembly with other components, simplifies the overall assembly structure, is simple to manufacture, and improves assembly efficiency and reliability. The bottom wall of the U-shaped core 211 is in contact with the conductive plate 1. The strip core 212 is mounted with a bimetal 3, and the thermal element 23 is disposed between the strip core 212 and the bimetal 3. The heat element 23 is a square ring structure that cooperates with the strip core 212 and is matched to the strip core 212; the second screw 22 fixes the bimetal 3, the heat element 23 and the strip core 212 Together. The strip core 212 is formed by laminating a plurality of iron core pieces, and the first screw 213 sequentially fixes the strip core 212 to the U-shaped iron core 211 through the mounting holes on the plurality of iron core chips.

As shown in FIG. 2 and FIG. 4, the bimetal 3 of the present invention is an integrally formed structure including a first metal piece 31 and a second metal piece 32 which are connected in an L shape, wherein the first metal piece 31 extends into the iron. The inside of the through hole 20 of the core 2 is fixed to the inner side wall of the core 2 by a second screw 22. The assembly structure is simple and reliable, improving assembly efficiency and stability. Further, one end of the second metal piece 32 is connected to the first metal piece 31, and the other end of the second metal piece 32 is mounted with an adjusting bolt 4 for adjusting the end of the adjusting bolt 4 and the traction of the thermal trip device. The distance between the rods 5 is to adjust the delay time of the tripping action of the thermal trip device. By adopting adjustable adjusting bolts, the adjusting bolts can be screwed in or out according to the actual situation to realize the delay time of approaching or moving away from the drawbar to adjust the tripping, and the operation is simple and convenient, and the adjustment effect is flexible and convenient. Of course, the bimetal 3 may also be a straight strip-like structure which is directly fixed to the core 2 by welding one end of the bimetal 3.

The first screw 213 and the second screw 22 of the present invention can be replaced by other commonly used fasteners such as rivets, or by a fixed connection of welding instead of a screw.

The above is a further detailed description of the present invention in conjunction with the specific preferred embodiments, and the specific implementation of the present invention is not limited to the description. For those skilled in the art to which the present invention pertains, a number of simple deductions or substitutions may be made without departing from the spirit and scope of the invention.

Claims

A thermal trip device for a molded case circuit breaker, comprising: a conductive plate (1), a core (2) and a bimetal (3), the core (2) being provided with a through hole (20) a ring-shaped core structure, the conductive plate (1) penetrating through the through hole (20) of the core (2), the bimetal (3) is mounted on the core (2), and is not connected to the conductive plate (1) Contact connection.
A thermal trip device for a molded case circuit breaker according to claim 1, wherein said conductive plate (1) comprises a first conductive plate (11) and a second conductive plate (12) which are sequentially connected in a current direction. The second conductive plate (12) of the conductive plate (1) extends into the through hole (20) of the iron core (2), wherein the width of the through hole (20) of the iron core (2) is larger than that of the second conductive plate ( 12) is wider than the width of the first conductive plate (11).
The thermal trip device of a molded case circuit breaker according to claim 1, characterized in that: the iron core (2) is provided with a thermal element (23), and the bimetal (3) is connected to the thermal element (23). And the specific heat capacity of the heat element (23) is smaller than the specific heat capacity of the iron core (2).
A thermal trip device for a molded case circuit breaker according to claim 3, wherein said core (2) comprises a U-shaped core (211) and is disposed on the open end of the U-shaped core (211) a strip core (212), the two ends of the strip core (212) are lapped and fixed on the two arms of the U-shaped core (211) by a first screw (213) to form the strip A toroidal core structure having a through hole (20).
A thermal trip device for a molded case circuit breaker according to claim 4, wherein said strip-shaped core (212) is mounted with said bimetal (3) in a strip core (212) The thermal element (23) is disposed between the bimetal (3), and the thermal element (23) is a square ring structure matched with the strip core (212), and is matched and set in the strip core ( 212); the second screw (22) holds the bimetal (3), the thermal element (23) and the strip core (212) together.
A thermal trip device for a molded case circuit breaker according to claim 1, wherein said bimetal (3) comprises a first metal piece (31) and a second metal piece (32) connected in an L-shape. Wherein the first metal piece (31) protrudes into the through hole (20) of the core (2) and is fixed to the inner side wall of the core (2) by the second screw (22).
The thermal trip device of a molded case circuit breaker according to claim 6, wherein one end of the second metal piece (32) is connected to the first metal piece (31), and the second metal piece (32) Another An adjusting bolt (4) is mounted on the end for adjusting the distance between the end of the adjusting bolt (4) and the drawbar (5) of the thermal trip device.
The thermal trip device of a molded case circuit breaker according to claim 1, wherein the bimetal (3) is a straight strip-shaped structure, and one end of the bimetal (3) is directly welded and fixed to the iron. On the core (2).
The thermal trip device of a molded case circuit breaker according to claim 2, wherein a ratio of a width of the first conductive plate (11) to a width of the second conductive plate (12) is 9:7; The ratio of the width of a conductive plate (11) to the width of the through hole (20) is 5:4.
The thermal trip device of a molded case circuit breaker according to claim 1, wherein the through hole (20) has a width of 36 mm, and the conductive plate (1) penetrates the portion of the through hole (20). Width × thickness is 35mm * 15mm.