Structure classification of electromagnetic relays and comparison of typical magnetic system containing permanent magnet

The electromagnetic relays have lots of structures and are applied widely in the automation control system in aerospace. Firstly, the structures of aerospace electromagnetic relays (AEMR) were classified. According to the structure arrangement, there are three layers, two layers and one layer structures; from electromagnetic system, there are clapper type, balance armature type, polarized magnetic system and balance force magnetic system; from armature returning mode, there are spring returning, permanent magnet returning, permanent magnet magnetic circuit returning and polarized magnetic circuit returning modes. All of these structures were compared separately. Then, the equivalent magnetic circuit model of the typical polarized magnetic system and balance force magnetic system are founded. The ultimate difference between these magnetic systems was illuminated based on the polarized magnetic system criterion. The research conclusions can be used to direct the design of AEMR.