Abstract:

The double-break contact structure of molded case circuit breaker is theoretically symmetrical,but due to the existence of the floating gap in the center of the rotor shaft,when a short-circuit fault occurs,the arcing of the two ports will not be completely consistent.When the imbalance reaches a certain level,it will cause the failure of short circuit protection.In order to study the influence of different rotor springs on the arcing balance of the double-breakpoint circuit breaker.The phase of short-circuit fault is changed through experiments,and arcing balance under different structures is compared by intuitive graphs and data.The results show that the spring structure has a significant impact on the arcing balance,and the compression spring design has more advantages in terms of balance,which provides support for perfecting the circuit breaker rotor design.

Key words: molded case circuit breaker, arcing balance, spring design, fault occurring phase