Improvement in Electrical Life of a Moulded Case Circuit Breaker for Feeder Protection

Abstract

The electric contacts are widely used in many applications such as circuit breakers, electrical switches and contactors. The project includes detailed study of the factors such as resistance of the contact material, millivolt drop across the contact and the hardness of the material, that directly affects the arc erosion of the contact button hence, affecting the electrical life of the moulded case circuit breaker (MCCB). The materials used in electrical contacts must have a good combination of conductivity, resistance to welding and erosion and wearing qualities. The present design of contact composition is analysed by carrying out a detailed study of various available silver button composition to scrutinize silver button composition based on findings from the literature review. The limitations in the present design will be found out using finite element analysis (FEA) soft tool JMAG. Then, based on findings of detailed study and analysis done on FEA soft tools, new concepts for electric contacts of MCCB will be generated. The proposed concept for electric contact will be finalized by analysis on soft tools like JMAG and mathematical modelling. The prototype of new electric contact buttons will be practically validated on MCCB. After successful completion of concept validation, the proposed electric contact buttons will be considered for improvement of electrical life of the circuit breaker.