Abstract: To evaluate the reliability of electromagnetic relays,the degradation and failure of a contact spring system for electromagnetic relay under cyclic loading was analyzed.The performance degradation of the contact spring system was then modelled and analysed using stochastic uncertainty theory.Finally,based on the contact gap degradation model,a reliable life evaluation of the electromagnetic relay by considering the degradation of the key assembly parameters of the contact spring system was conducted.The research results lay a foundation for the design of reliable electromagnetic relays.

Key words: electromagnetic relay, gap degradation, degradation modeling, reliability assessment