Circuit breaker is an essential automatically operated electrical switch for many modern industries. However, the problem of this essential equipment lies in that it often gets damaged for overload or short circuits. Given this situation, a circuit protection device of reliable operations is highly demanded among those companies. In light that its performance mainly depends on the operating mechanism, we should give enough attention to its operating mechanism. That is to say we need a reliable circuit breaker which is equipped with an advanced and reliable operating mechanism.