Research on a Calculation Method of Permanent Magnet for Balanced Force Relay based on Attractive-Counter Force Coordination Curve

The performance of the balanced force hermetically sealed electromagnetic relay (HSER) mainly reflects on the relationship between its attractive force and the counter force. Permanent magnet (PM) has key role in the design process of the electromagnetic attractive force. In this paper, an operating point-return line model of PM is built. A finite element model (FEM) is established to calculate static attractive force. A test system is built to validate the accuracy of the model. The attractive force and counter force curve under different voltage are solved. Under a counter force curve fixed condition, attractive force curve has been matched in design process by adjusting dimensions and materials of the PM. Based on this curve, an electromagnetic system has been designed. The accuracy of this method is verified by its prototype. Finally, the matching optimization rules and computational efficiency of this method are discussed.