Research and application of polarized magnetic system criteria

With the advantages of small size, light weight, low power dissipation and fast action, polarized magnetic system has been widely applied to military and civil electromagnetic relay. In the process of real design, different demands result in various structures of polarized magnetic system designed. At present, there is not any criterion for distinguishing polarized magnetic system. From the point of view of the structure and moving characteristic of permanent magnet in relay, polarized magnetic system is classified into four typical structures. By investigating typical structures, equivalent magnetic circuits and mathematical models, the criteria for distinguishing polarized magnetic system were achieved from the aspects of magnetic potential and magnetic flux. Then a magnetic system with permanent magnet was judged if it was polarized magnetic system or not by the criteria. The conclusion can be used to direct the design of electromagnetic relay with permanent magnet.