Abstract:

As a critical accessory for molded case circuit breaker (MCCB), the undervoltage release plays a vital protective role by reliably tripping the circuit breaker upon abnormal voltage drops, safeguarding circuits and equipment. Aiming at the problem of insufficient action reliability of the traditional self-holding type and auxiliary-holding type undervoltage releases in high-temperature environments, the structural design key points of the self-holding type undervoltage release are elaborated in detail, and the dynamic characteristics are deeply simulated and analyzed based on Ansys software. The design scheme is effectively verified by the method of combining simulation and testing. The results demonstrate that the optimized undervoltage release significantly enhances its actuation reliability under high-temperature and other harsh operating conditions, thereby effectively improving the undervoltage protection performance of MCCB.

Key words: molded case circuit breaker (MCCB), undervoltage release, design, simulation, high temperature