Low voltage circuit breaker with pneumatic trip device

Abstract

The invention relates to a low-voltage circuit breaker with a pneumatic tripping device. The low-voltage circuit breaker comprises a base and a shell. A plurality of independent monopole contact devices are arranged in parallel on the base. An operating mechanism of the circuit breaker with a tripping traction rod is fixedly arranged on one of the monopole contact devices. The monopole contact device comprises a second shell, wherein both ends of the monopole contact device are provided with a moveable contact bridge with a moveable contact and a stationary contact corresponding to the moveable contact. The moveable contact bridge with the moveable contact can move linearly up and down, so that the two moveable contacts are respectively connected or disconnected with the stationary contact correspondingly. An arc extinguishing region is formed among the moveable contact, the stationary contact and the second shell. The pneumatic tripping device is arranged between two adjacent monopole contact devices. The pneumatic tripping device detects the gas pressure in the arc extinguishing regions installed on both sides of the monopole contact device, and drives the operating mechanism to trip when the gas pressure exceeds the predetermined threshold value. Compared with the prior art, the circuit breaker provided by the invention has the advantages of accelerating the short-circuit breaking speed and improving the short-circuit breaking capacity of the circuit breaker and the like.

Description

technical field [0001] The invention relates to a low-voltage circuit breaker, in particular to a low-voltage circuit breaker with a pneumatic tripping device. Background technique [0002] Low-voltage circuit breakers are used to control and protect the operation of low-voltage power distribution systems or electrical equipment, and prevent overcurrent phenomena such as overload or short-circuit in the circuit from causing damage to electrical equipment or the circuit itself. [0003] When an overcurrent occurs in a certain section of the circuit, when it reaches or exceeds a preset disconnection threshold, the circuit breaker controlling the section of the circuit will automatically open to cut off the faulty circuit to avoid the expansion of the fault. [0004] When the circuit breaker cuts off the current, especially the short-circuit current, it will bear a large electromotive force and thermal effect, so the ability of a specific circuit breaker to break the current is...

AI Technical Summary

Problems solved by technology

[0009] Chinese patent CN2476875Y describes a single-pole contact module with a tripping device. This scheme introduces a modular single-pole assembly using a direct-acting double-break point contact element, which overcomes the traditional rotary contact system due to its operation The direction of the driving force of the mechanism cannot always be consistent with the direction of motion of the drive shaft. The force on the moving contact forms an angle with its direction of motion when it is rotating, and friction is generated between the moving parts, resulting in double breakpoints. The problem of inconsistent pressure between the two contacts

[0010] China Patent Authorization Announcement No. CN1041361C describes a molded case low voltage circuit breaker series with double break point contact elements and pneumatic tripping technology, which is a circuit breaker with rotary double break point contact assembly, the disadvantages of which are all The contact components share a single pneumatic release, and there are many intermediate links in the high-pressure gas channel, the structure is complex and the airtightness is poor, resulting in unequal tripping thrust of each pole and inconsistent critical operating current

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