This paper conducts a thorough research to the problem of short circuit override trip and inaccurate leakage protection action mainly existing in HV flameproof switchgear comprehensive protection.
The paper introduces the working principle, control, protection and related performance of QJZ—400/1140(660) mine flameproof and intrinsically safe vacuum electromagnetic starter.
The existing defect of overload, open phase protection of minitype flameproof motor used in coal mine was analysed and its improved protection scheme was presented.