Design of Universal Fixture for MCCB and Capacity Enhancement of assembly line of Air Circuit Breaker

Abstract

The Moulded Case Circuit Breaker (MCCB) is an electrical protection device used in power distribution systems. Its purpose is to protect electrical equipment and circuits from overcurrent and short circuits. An electrical device called air circuit breaker (ACB) is used to safeguard the electric circuits with currents ranging from 800 amps to 10,000 amps from overcurrent and short circuit. Since each operation Contact pressure (CP), Trip-force (TF), Over-travel (OT), and Trip-travel (TT), requires a different setup for MCCB and the time required in each operation is significant high. Also, in the Air circuit breaker (ACB) production line, the time of production for ACB is also high. So, the objective of this research is to minimize the overall production time of ACB and to design a universal fixture for MCCB to perform all testing operations in one setup. Hence, to investigate the problem, cause and effect analysis was carried out. From the cause and effect analysis and a detailed time study, it is found that in ACB production line, the majority of time is being spent on mounting and front housing assembly station. To resolve the issue for MCCB, a design of universal fixture is proposed. And for reducing the production cycle time of ACB assembly line, an automated mounting station is designed in which bolt fastening can be done with the help of a Nut-runner. By implementing this concept in the mounting station, 30% of the mounting time can be reduced. Additionally, for front housing assembly station an automated conveyor is suggested to provide front housings automatically at regular time intervals. By implementing these changes, the overall production time can be reduced in both MCCB and ACB.