Molded case circuit breaker
The present disclosure relates to a molded case circuit breaker, and particularly, to a molded case circuit breaker having an enhanced arc protecting function. The molded case circuit breaker includes: a power side terminal portion provided at a front side of an enclosure and having a fixed contact arm; a finger assembly coupled to the fixed contact arm, and disposed on a front surface of the power side terminal portion; and a base bus supporter coupled to an upper surface and a lower surface of the power side terminal portion, and having a finger hole through which the finger assembly is exposed. The base bus supporter is provided with a protection unit configured to enclose the finger assembly around the finger hole.
1. A molded case circuit breaker, comprising:
a power side terminal portion provided at a front side of an enclosure, and having a fixed contact arm;
a finger assembly coupled to the fixed contact arm, and disposed on a front surface of the power side terminal portion; and
a base bus supporter coupled to an upper surface and a lower surface of the power side terminal portion, and having a finger hole through which the finger assembly is exposed,
wherein the base bus supporter is provided with a protection unit configured to enclose the finger assembly around the finger hole,
wherein a partition wall for phase-to-phase insulation is provided in the base bus supporter, and
wherein the protection unit is provided between the partition wall and a further partition wall, or between the partition wall and a side wall.
2. The molded case circuit breaker of claim 1 , wherein the finger assembly includes:
a finger formed to have a shape of pincers;
a finger spring configured to provide a contact pressure to the finger; and
a finger holder configured to fix the finger and the finger spring.
3. The molded case circuit breaker of claim 1 , wherein the protection unit protrudes backward from a front surface of the base bus supporter.
4. The molded case circuit breaker of claim 3 , wherein the protection unit is formed to have a length long enough to overlap an exhaustion cover plate coupled to the power side terminal portion.
5. The molded case circuit breaker of claim 1 , wherein an arc exhaustion space is provided between the protection unit and the partition wall.
6. The molded case circuit breaker of claim 1 , wherein the protection unit is formed such that upper and lower surfaces of the protection unit have different lengths from each other.
7. The molded case circuit breaker of claim 1 , wherein an interference preventing groove configured to prevent interference with a connector for connecting the finger assembly to the fixed contact arm is formed on an upper surface or a lower surface of the protection unit.
8. The molded case circuit breaker of claim 1 , wherein a plurality of ribs are formed between the protection unit and the partition wall.