Arc extinguishing chamber of circuit breaker

Abstract

An arc-extinguishing chamber for a circuit-breaker, comprising a static contact module (10), a movable contact module (12), an air cylinder (14), a piston (18), an air storage chamber (22) and a valve unit. An air-compression chamber (20) is formed between the piston (18) and the air cylinder (14). The movable contact module (12) and the air cylinder (14) are connected together. The valve unit is arranged between the air-compression chamber (20) and an air storage chamber (22). When the pressure difference between the air-compression chamber (20) and the air storage chamber (22) is higher than a predetermined value, gas from the air-compression chamber flows into the air storage chamber; when the pressure of the air storage chamber is higher than that of the air-compression chamber, gas from said air storage chamber returns to the air-compression chamber, thus constituting a process whereby the air storage chamber first stores gas for the air-compression chamber, then returns said gas to said air-compression chamber. This avoids excess of pressure occurring in the air-compression chamber when the circuit-breaker breaks open, reduces operating power required by the operating mechanism, increases the length of effective air-blowing time with respect to an arc, increases the breaking capacity of the circuit-breaker and thus product reliability, and lowers the cost of the operating mechanism.

Description

technical field [0001] The invention relates to an arc extinguishing chamber of a circuit breaker. Background technique [0002] The compressed gas type interrupter of the circuit breaker is to extinguish the arc by compressing the gas in the compressed gas chamber to generate the air flow. The existing circuit breaker interrupter includes a static contact module, a moving contact module, a compressed air cylinder and a piston. The piston A compressed air chamber is formed between the compressed air cylinder. The movable contact module is connected with the air cylinder, and the air cylinder drives the movable contact module to move relative to the piston, so as to change the volume of the air chamber. During the opening operation, the gas in the compression chamber is compressed, and the arc combustion causes the gas to expand, so that the gas pressure in the compression chamber rises. When the pressure of the gas in the compression chamber rises to an optimal value (crit...

AI Technical Summary

Problems solved by technology

However, this is not the case. As the energy of the gas in the compression chamber is continuously compressed and the arc burns, it becomes inevitable that the gas pressure in the compression chamber continues to rise. When the pressure of the compression cylinder reaches a high level, a strong The reaction force of the cylinder hinders the opening movement of the circuit breaker, and even reduces the opening speed to zero. figure 1 And attached figure 2 As shown in the travel curve in the oscillogram, there is an obvious stagnation or even rebound during the opening movement of the circuit breaker

[0003] In order to overcome this cylinder reaction force, it is necessary to use a heavy-duty operating mechanism with large operating power and complex structure, such as a hydraulic mechanism, to complete the opening operation of the circuit breaker.

However, according to the survey, the hydraulic mechanism often has leakage problems, and the price is relatively high

[0004] In view of the above-mentioned deficiencies, one of the methods commonly used at present is to discharge the excessively high pressure of the gas in the compressed air chamber in some way (such as installing a pressure relief valve). Although this method reduces the pressure in the compressed air chamber, the At the same time, the gas quality in the compressed air chamber is reduced, the gas density in the nozzle is reduced, the insulation performance is reduced, the ability of the gas to blow the arc in the later stage is reduced, and the gas used to extinguish the arc is wasted.

[0005] In view of the above shortcomings, the second method commonly used at present is to directly increase the remaining volume of the compression chamber. Although this method can limit the pressure of the gas in the compression chamber when breaking a large current and a long arc, it is not suitable for breaking a small current and a short arc. , there will be problems of slow gas pressure rise and insufficient air pressure in the compression chamber

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