Analysis on electromagnetic repulsion force in Molded Case Circuit Breaker

In this paper, research on the electromagnetic repulsion force in Molded Case Circuit Breaker (hereafter MCCB) is presented. Between two contact-tips, there is a point of contact that is a very small area. Therefore, a current between a fixed-tip and operative-tip flows through a very small area, which is the point of contact. Then, due to current concentration, magnetic flux density between two contact-tips produces the electromagnetic repulsion force. Because repulsion force can improve interrupting ability of MCCB, it is important to analyze the electromagnetic repulsion force, which occurs between two contacts. To analyze electromagnetic repulsion force, the Finite Element Method (hereafter FEM) is adapted. Further, through the interrupting test, correlation between repulsion force and interrupting ability was confirmed. We calculated the electromagnetic repulsion force via five models and tested interrupting ability via one model.