Design and stationary characteristic analysis of magnetic system of small capacity permanent magnet DC contactor
Permanent magnet DC contactor has the advantages of simple structure, low energy consumption and low noise. A magnetic system structure applicable to DC contactor is presented in this paper. Based on the traditional structure of single coil and single stable position contactor, an auxiliary gas gap is added. By changing the size of the gas gap to change the attraction of permanent magnet, the whole magnetic system improves the reliability of breaking-closing operating. A mathematical model of the magnetic system is established, and the magnetic field and the stationary characteristic are calculated by using finite element method. According to the calculations, cooperation between attraction characteristics and counterforce characteristics is analyzed and the result indicates that the magnetic system, which has a advantages of strong electromagnetic actuation, reliable breaking, manual resetting without disassembly, can be used in industrial production.