Improvement in Electro-Mechanical Endurance Test Life of Moulded Case Circuit Breaker using Stored Energy Electrically Operating Mechanism

Abstract

The present work addresses improvement in Electro-Mechanical Endurance Test (EET) life using stored energy operated mechanism. In MCCB, the operation like on, off, trip and reset are working on the basis of Mechanism. The Four-linkage mechanism plays very important role in the performance of MCCB. Motorized mechanism is an external accessory used to operate MCCB. It is directly mounted on MCCB. Comparing the standalone working of MCCB with the Combination (i.e. Motorized mechanism with MCCB), Total no. of operation in combination compared to stand alone MCCB is very less. To improve the testing life, several calculations, simulation, testing and validation has been performed. This includes calculation of force of sun and planetary gear applied on the knob of MCCB. The process is followed by strengthening of the knob by changing the material. High speed photography was performed for the purpose of time calculation of opening of upper contact, which is most important factor, which affects the EET life. Computation fluid dynamic was performed to check the pressure and temperature generated inside the MCCB. The process is followed by increasing the repulsion force of the contact system by changing the design. The final testing has been done on the test bench, which gives satisfying results.