Multi-pole circuit breaker

Abstract

A multi-pole circuit breaker includes at least one first pole unit at least one second pole unit, each first pole unit includes a first static contact, a first movable contact and a first arc extinguishing device, each first arc extinguishing device includes a plurality of first grids, the plurality of first grids are stacked in a spaced state, each second pole unit comprises a second static contact, a second movable contact and a second arc extinguishing device, each second arc extinguishing device comprises a plurality of second grids, and the plurality of second grids are stacked in a spaced state. The multi-pole circuit breaker further comprises an equipotential connection member which is connected with one in the first grids and one of the second grids or connected with one of the first grids and the second static contacts, and the first grids between the equipotential connection member and the first static contacts and / or the second grids between the equipotential connection member and the second static contacts are employed to cut and break the arc between the first static contacts and the second static contacts. The burning time of the arc on the movable contact is shortened, the breaker breaking capacity is improved, and the electric life is prolonged.

Description

Technical field [0001] The invention belongs to the technical field of low-voltage electrics, and specifically relates to a multi-pole circuit breaker. Background technique [0002] Multi-pole circuit breaker is used as a protection component of the power grid. Its function is to cut off the circuit in time when there is a short-circuit current or an overload current in the circuit to ensure that the electrical appliances in the circuit are not damaged. When the circuit breaker is opened, an arc will be generated between the moving and static contacts. Due to the large arc energy, the arc cannot stay between the moving and static contacts for a long time, otherwise it will cause severe ablation of the contacts, or even Burned out circuit breaker. [0003] How to quickly guide the arc from the contact area to the arc extinguishing grid area has become the key technology of the circuit breaker. The usual methods include setting up a magnetic arc-igniting piece near the static contac...

AI Technical Summary

Problems solved by technology

[0006] Taking phase A as an example, once a three-phase short circuit occurs, the load terminal of phase A and the load terminal of phase B will be conducted, and at the same time, the dynamic and static contacts of each phase will open to form an arc. At this time, the current path is as shown in the figure, followed by phase A Incoming line terminal, static contact of phase A, grid plate of phase A, moving contact of phase A, short circuit occurrence point, moving contact of phase B, grid plate of phase B, static contact of phase B, incoming line terminal of phase B, the arc will Burn between the moving contact and the arc grid until the arc is extinguished, which will cause a large amount of ablation of the contact

[0007] During the three-phase short circuit breaking process of the circuit breaker, there will always be a current path from the moving contact to the static contact. In other words, the arc will always burn between the moving contact and the arc grid for a period of time until the arc is broken The degree of ablation of the contacts depends on the energy of the arc. The higher the energy of the arc, the more serious the burning of the contacts. Especially, in the DC circuit, since there is no zero-crossing point, the difficulty of extinguishing the arc will increase. improve

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