Low-voltage circuit breaker capable of improving breaking capacity

Abstract

The invention discloses a low-voltage circuit breaker capable of improving breaking capacity. The low-voltage circuit breaker comprises a contact component comprising a moving contact and a fixed contact, wherein the moving contact and the fixed contact are respectively provided with contact parts; the contact parts of the moving contact and the fixed contact are respectively of double-layer structures of Ag-based alloy and Cu-based alloy, and the Ag-based alloy of the moving contact is in contact with the Ag-based alloy of the fixed contact when the moving contact and the fixed contact are adsorbed; metal oxide with a resistance value capable of positively changing along with the temperature is also arranged between the Ag-based alloy and the Cu-based alloy in the moving contact or the fixed contact; and the metal oxide is completely separated between the Ag-based alloy and the Cu-based alloy. By arranging a current limiting structure in the circuit breaker, the circuit breaker has a current limiting function, thereby being greatly convenient to use in different occasions.

Description

technical field [0001] The invention relates to a circuit breaker, in particular to a low-voltage circuit breaker which improves breaking capacity by means of current limiting. Background technique [0002] Low-voltage circuit breaker, also known as automatic switch, is an electrical appliance that not only has the function of manual switch, but also can automatically protect against voltage loss, undervoltage, overload, and short circuit. Its function is equivalent to the sum of some or all of the functions of the knife switch, over-current relay, voltage loss relay, thermal relay and leakage protector. It is an important protective device in the low-voltage distribution network. Low-voltage circuit breakers are usually used to switch on and off load circuits, and can also be used to control motors that start infrequently. Because low-voltage circuit breakers have multiple protection functions (overload, short circuit, undervoltage protection, etc.), adjustable operating v...

AI Technical Summary

Problems solved by technology

The breaking capacity of low-voltage circuit breakers is usually reflected in the current value that can be broken. At the moment of circuit short circuit, the short-circuit current passing through the contact parts is very large. When the short-circuit current exceeds the breaking current value of the low-voltage circuit breaker, fusion welding will occur. phenomenon, so that the moving contact cannot be disengaged from the static contact. Therefore, it is necessary to improve the breaking capacity of the low-voltage circuit breaker as much as possible. The existing way to improve the breaking capacity of the low-voltage circuit breaker is at the incoming line end Or a current limiter is connected to the outlet end, and the current limiter is used to limit the current when the circuit is short-circuited, so that the short-circuit current passing through the contact parts will not exceed the set passing current value, and the breaking current of the low-voltage circuit breaker will be virtually reduced. The value is increased, that is, the breaking capacity of the low-voltage circuit breaker is improved. However, because this method is to connect the current limiter at the inlet and outlet ends of the circuit breaker, it is inconvenient to use the circuit breaker.

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