Moulded case circuit breaker with high breaking capacity

Abstract

Disclosed is a moulded case circuit breaker with high breaking capacity. The circuit breaker comprises a shell, a static contact, a dynamic contact, a tripping mechanism and an arc extinguishing chamber; after improvement, an insulated arc extinguishing device is added, the insulated arc extinguishing device comprises a shielding gate plate, a magnet yoke, a swing arm and a torsion spring, and the magnet yoke is fixed on the static contact; the front end of the shielding gate plate is opposite to the clearance between the dynamic and static contacts, and two side edges of the shielding gate plate are respectively connected with slide rails on two sides of the dynamic and static contacts in a sliding manner; the upper end of the swing arm is articulated with the rear end of the shielding gate plate, the lower end of the swing arm is articulated with a support fixed on the side of the static contact via a fixing pin roll penetrating a center hole of the torsion spring, and an armature corresponding to the magnet yoke is arranged in the middle of the swing arm; and two ends of the torsion spring respectively press the swing arm and the support. The shielding gate plate can be quickly inserted between the dynamic contact and the static contact when the circuit breaker breaks the short-circuit current to extinguish arc, thereby shortening the amplification time of arc energy, realizing short flashover or no flashover of the circuit breaker, and then greatly improving the short-circuit current breaking capacity of the circuit breaker.

Description

technical field [0001] The invention relates to a molded case circuit breaker with strong short-circuit current breaking capacity, which belongs to the technical field of power switches. Background technique [0002] Molded case circuit breaker (MCCB) is an important electrical component in industrial and civil low-voltage power distribution equipment, and is mostly used as a branch circuit switch for low-voltage power distribution system protection. Among them, the short-circuit fault protection is its most important function. Since the short-circuit current of the line is very large when the short-circuit fault occurs, a plasma arc with high energy will be generated between the moving and static contacts of the circuit breaker when breaking the short-circuit current. Only the arc extinguishing parts provided can quickly extinguish the arc, and the circuit breaker can complete the task of breaking the short-circuit current. [0003] At present, MCCBs both at home and abroa...

AI Technical Summary

Problems solved by technology

The arc extinguishing effect of this method is affected by factors such as the material of the arc extinguishing chamber, the breaking speed of the contacts, the distance between the contacts, the material of the contacts, etc. Relatively poor, generally no more than AC 400V, 50kA, and the DC short-circuit current is more difficult to break because there is no zero-crossing process

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