A molded case circuit breaker

Abstract

This utility model discloses a molded case circuit breaker. Key technical features include a housing, a terminal section for connecting an external power source and load, an arc-extinguishing chamber assembly, and an exhaust section. The exhaust section includes an exhaust cover, a guide, and a diversion section. The arc-extinguishing chamber assembly includes an arc gas outlet for discharging arc gas, which is connected to the diversion section. An exhaust chamber is located near the arc gas outlet in the exhaust section, with a communication gap between the arc gas outlet and the exhaust chamber. An elastic plate covers the gap inside the exhaust chamber. When a circuit is interrupted, the generated arc gas pressure is high. The high-pressure gas pushes the elastic plate, allowing some of the arc gas from the outlet to communicate with the exhaust chamber and enter through the gap, achieving good discharge and alleviating internal high pressure. Simultaneously, the diversion channel formed by the diversion section and the guide ensures smooth and rapid discharge of arc gas while maintaining insulation.

Description

Technical Field

[0001] This utility model relates to the field of circuit breaker technology, and more specifically to a molded case circuit breaker. Background Technology

[0002] Currently, molded case circuit breakers (MCCBs) are mainly used to protect circuits from damage caused by overcurrent, overload, short circuit, arc fault, or ground fault. They typically integrate the switching mechanism and tripping unit into an insulating housing. The circuit is switched on or off by mechanically separating the contacts. These contacts can be manually operated, remotely controlled by electrical signals, or automatically tripped in case of a fault.

[0003] However, the existing technology still has some drawbacks. When the contacts of a conventional molded case circuit breaker are disconnected, the high-energy arc generated between the contacts releases a large amount of heat and generates plasma-state arc gas. If this high-voltage arc gas cannot be discharged quickly, it may cause dielectric breakdown, resulting in irreversible damage. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the present invention provides a molded case circuit breaker.

[0005] To achieve the above objectives, this utility model provides the following technical solution: It includes a housing, and further includes a terminal section for connecting an external power source and a load, an arc-extinguishing chamber assembly, and an exhaust section. The exhaust section includes an exhaust cover, a guide, and a diversion section. The arc-extinguishing chamber assembly includes an arc gas outlet for discharging arc gas, and the arc gas outlet is connected to the diversion section. An exhaust chamber is provided near the arc gas outlet in the exhaust section, and a communication gap is provided between the arc gas outlet and the exhaust chamber. An elastic plate covering the gap is provided inside the exhaust chamber.

[0006] The present invention is further configured such that the exhaust chamber is provided with a plurality of staggered baffles.

[0007] The present invention is further configured such that: the inner surface of the arc gas outlet is conical, and the width increases in the direction of arc gas emission; the guide is conical, and its width gradually increases towards the load-side terminal in the direction perpendicular to the arc gas emission direction; the guide is connected to the arc gas outlet, together forming a continuous conical channel.

[0008] The present invention is further configured such that: the diversion part is provided with a diversion block, the diversion block is triangular, the diversion block and the guide form a channel, the vertex of the diversion block is spaced apart from the arc gas outlet, the arc gas outlet and the inlet of the guide are in close contact without gap, and the width of the inlet end of the guide is the same as the width of the outlet end of the arc gas outlet.

[0009] The present invention is further configured such that: the exhaust cover is installed on the lower surface of the housing and is used as a switch for the exhaust section.

[0010] The present invention is further configured such that: the exhaust cover is provided with spaced partition walls along the direction perpendicular to the arc gas emission direction, the partition walls are used to separate adjacent diversion sections, and the exhaust section is provided with an insertion groove adapted to the partition walls.

[0011] The present invention is further configured such that: the arc-extinguishing chamber assembly is provided with a set of separable main contacts and at least a set of separable secondary contacts, wherein the secondary contacts are connected in series with the main contacts, and when the main contacts are disconnected, the secondary contacts will also be disconnected.

[0012] The present invention is further configured such that: the arc-extinguishing chamber assembly includes a thermomagnetic device for controlling the main contacts and a PCB assembly for controlling the secondary contacts, the PCB assembly including a current sensor for sensing circuit current, an opening and closing device for opening the secondary contacts, and a PCB monitoring module.

[0013] In summary, this invention has the following beneficial effects: When a circuit break occurs, the generated arc gas pressure is high. The high-pressure gas will push the elastic plate, allowing part of the arc gas outlet to connect with the exhaust chamber and enter the exhaust chamber through the gap, achieving good discharge and alleviating the internal high pressure. At the same time, the diversion channel formed by the combination of the diversion part and the guide can promote the smooth and rapid discharge of arc gas while ensuring insulation. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this embodiment;

[0015] Figure 2 This is a partial top sectional view of this embodiment;

[0016] Figure 3 This is a partial cross-sectional view at point A in this embodiment;

[0017] Figure 4 This is a schematic diagram of the working principle of the PCB assembly in this embodiment;

[0018] Reference numerals: 1. Exhaust section; 11. Exhaust cover; 111. Partition wall; 112. Insertion groove; 12. Guide; 13. Diverter section; 131. Diverter block; 14. Exhaust chamber; 141. Gap; 142. Elastic plate; 143. Baffle; 2. Arc gas outlet; 3. Main contact; 4. Secondary contact; 5. Thermomagnetic device; 6. PCB assembly; 61. Current sensor; 62. Opening and closing device; 63. PCB monitoring module. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings.

[0020] This embodiment discloses a molded case circuit breaker, such as Figures 1 to 3 As shown, the device includes a housing, a terminal section for connecting an external power source and load, an arc-extinguishing chamber assembly, and an exhaust section 1. The exhaust section 1 includes an exhaust cover 11, a guide 12, and a diversion section 13. The arc-extinguishing chamber assembly includes an arc gas outlet 2 for discharging arc gas. The arc gas outlet 2 is connected to the diversion section 13. In a three-phase circuit, each phase current is independent. The partition wall 111 ensures that each phase current is independently matched with a single diversion section 13, preventing one phase exhaust from polluting multiple phases. An exhaust chamber 14 is located near the arc gas outlet 2 in the exhaust section 1, and a communication gap 141 is provided between the arc gas outlet 2 and the exhaust chamber 14. An elastic plate 142 covering the gap is provided inside the exhaust chamber 14. When the terminal section is disconnected, an arc is generated between the disconnected terminals, producing arc gas. The internal pressure increases, and the increased pressure pushes the elastic plate 142, causing the gap 142 between the exhaust section 1 and the exhaust chamber 14 to open. The arc gas can then enter the exhaust chamber 14 through the gap 142 for discharge, allowing the arc gas to be discharged quickly.

[0021] To further improve the design, the exhaust chamber 14 is provided with a plurality of staggered baffles 143. The baffles 143 can form a labyrinth structure, allowing the arc gas entering the exhaust chamber 14 from the exhaust section 1 to mix fully with the gas in the exhaust chamber 14, which helps to dilute and cool the ionized gas and prevent electrical breakdown during the emission process.

[0022] Further improvements include a conical inner surface for the arc gas outlet 2, with its width increasing towards the arc gas emission direction; a conical guide 12, whose width gradually increases towards the load-side terminal in the direction perpendicular to the arc gas emission direction; and the guide 12 connecting to the arc gas outlet 2 to form a continuous conical channel. The conical channel's width (X-axis) gradually increases in the direction perpendicular to the gas emission direction (Y-axis). According to Bernoulli's principle, the gas velocity decreases with increasing cross-sectional area, resulting in increased static pressure, enhanced ability to overcome downstream resistance, and reduced energy loss. Compared to a right-angle channel, the conical design has a lower local resistance coefficient, significantly improving emission efficiency.

[0023] Further improvements include a diversion block 131 in the diversion section 13. The diversion block 131 is triangular and forms a channel with the guide member 12. This triangular diversion block 131 diverts the discharged arc gas to both sides, avoiding the centerline terminal, reducing terminal corrosion and extending maintenance cycles. Its apex is spaced from the arc gas outlet 2, and the arc gas outlet 2 has seamless contact with the inlet of the guide member 12. The width of the inlet end of the guide member 12 is the same as the width of the outlet end of the arc gas outlet 2. This seamless contact creates a continuous channel, effectively preventing gas stagnation caused by channel gaps and the resulting eddies. The conical continuous structure ensures continuous gas flow, maintaining laminar flow within the conical channel and preventing flow separation caused by abrupt changes in cross-section.

[0024] Further improvements include the exhaust cover 11 being installed on the lower surface of the housing and used for opening and closing the exhaust section 1. The exhaust cover 11, located on the lower surface of the housing, can be easily installed and removed, allowing for convenient opening of the exhaust cover 11 to clean carbon deposits or worn parts inside the channel, facilitating maintenance.

[0025] Further improvements include a partition wall 111 spaced along the direction perpendicular to the arc gas emission direction on the exhaust cover 11. The partition wall 111 separates adjacent flow branches 13, and the exhaust branch 1 has an insertion groove 112 adapted to the partition wall 111. This ensures the insulation distance between each phase while preventing a cascading failure caused by an arc in one phase leading to breakdown in adjacent phases.

[0026] To further improve the design, the arc-extinguishing chamber assembly is equipped with a separable set of main contacts 3 and at least one separable set of auxiliary contacts 4. The auxiliary contacts 4 are connected in series with the main contacts 3. When the main contacts 3 are disconnected, the auxiliary contacts 4 will also disconnect simultaneously. When both the main and auxiliary contacts 4 are disconnected, at least two series arcs are generated, significantly increasing the circuit resistance. According to Ohm's law, when the circuit resistance increases, the arc energy and peak current generated in the circuit will decrease.

[0027] like Figure 4As shown, the arc-extinguishing chamber assembly includes a thermomagnetic device 5 for controlling the main contact 3 and a PCB assembly 6 for controlling the auxiliary contact 4. The thermomagnetic device 5 utilizes electromagnetic force and the thermal deformation of a bimetallic strip to achieve a rapid mechanical response, triggering the main contact 3 to open without an additional power supply. This mechanism can achieve a millisecond-level response when a severe short circuit is detected, ensuring rapid circuit disconnection. The PCB assembly 6 accurately monitors the circuit status through a current sensor 61 and an algorithm, triggering the auxiliary contact 4 to open when a fault is detected. The PCB assembly 6 includes a current sensor 61 for sensing circuit current, an opening / closing device 62 for opening the auxiliary contact 4, and a PCB monitoring module 63. The current sensor 61 can sensitively sense changes in the circuit and transmit the signal to the PCB monitoring module 63. The PCB monitoring module 63 controls the opening / closing device 62 to open the auxiliary contact 4, causing the main contact 3 to open thermomagnetically while simultaneously triggering the auxiliary contact 4 to open, maximizing the resistance increase effect of the series arc. If only a single control mechanism is relied upon, the arc energy suppression effect may be weakened due to timing deviations.

[0028] Working principle of this utility model

[0029] When a short circuit occurs in the circuit, the thermomagnetic device 5 is heated, causing the main contact 3 to separate. The PCB assembly 6 receives the state of separation of the thermomagnetic device 5, causing the auxiliary contact 4 to separate synchronously. The synchronous separation of the main contact 3 and the auxiliary contact 4 will generate two small electric arcs. The arc gas formed will enter the exhaust section 1. Part of the arc gas will enter the exhaust chamber 14 for discharge, and part of it will be discharged through the inner cone-shaped arc gas outlet 2. The gas is diverted to both sides by the diverting block 131 in the exhaust section 1, and cooperates with the cone-shaped guide 12 to allow the arc gas to be discharged smoothly.

[0030] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the design concept of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A molded case circuit breaker, comprising a housing, characterized in that: It also includes a terminal section for connecting an external power source and a load, an arc-extinguishing chamber assembly, and an exhaust section (1). The exhaust section (1) includes an exhaust cover (11), a guide (12), and a diversion section (13). The arc-extinguishing chamber assembly includes an arc gas outlet (2) for discharging arc gas, and the arc gas outlet (2) is connected to the diversion section (13). An exhaust chamber (14) is provided near the arc gas outlet (2) in the exhaust section (1). A communication gap (141) is provided between the arc gas outlet (2) and the exhaust chamber (14). An elastic plate (142) covering the gap (141) is provided inside the exhaust chamber (14).

2. A molded case circuit breaker according to claim 1, characterized in that: The exhaust chamber (14) is provided with several staggered baffles (143).

3. A molded case circuit breaker according to claim 1, characterized in that: The inner surface of the arc gas outlet (2) is conical, and its width increases in the direction of arc gas emission; the guide (12) is conical, and its width gradually increases towards the load-side terminal in the direction perpendicular to the arc gas emission direction; the guide (12) is connected to the arc gas outlet (2) to form a continuous conical channel.

4. A molded case circuit breaker according to claim 3, characterized in that: The diversion section (13) is provided with a diversion block (131), which is triangular in shape. The diversion block (131) and the guide (12) form a channel, with its apex spaced from the arc gas outlet (2). The arc gas outlet (2) and the inlet of the guide (12) are in close contact without gaps. The width of the inlet end of the guide (12) is the same as the width of the outlet end of the arc gas outlet (2).

5. A molded case circuit breaker according to claim 1, characterized in that: The exhaust cover (11) is installed on the lower surface of the housing and is used to open and close the exhaust section (1).

6. A molded case circuit breaker according to claim 5, characterized in that: The exhaust cover (11) is provided with spaced partition walls (111) perpendicular to the arc gas emission direction. The partition walls (111) are used to separate adjacent diversion sections (13). An insertion groove (112) adapted to the partition walls (111) is provided in the exhaust section (1).

7. A molded case circuit breaker according to claim 1, characterized in that: The arc-extinguishing chamber assembly is provided with a separable set of main contacts (3) and at least a separable set of secondary contacts (4). The secondary contacts (4) are connected in series with the main contacts (3). When the main contacts (3) are disconnected, the secondary contacts (4) will also be disconnected.

8. A molded case circuit breaker according to claim 7, characterized in that: The arc-extinguishing chamber assembly includes a thermomagnetic device (5) for controlling the main contact (3) and a PCB assembly (6) for controlling the secondary contact (4). The PCB assembly (6) includes a current sensor (61) for sensing the circuit current, an opening and closing device (62) for opening the secondary contact (4), and a PCB monitoring module (63).

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