A steady-state thermal network analysis modeling method for hermetically sealed electromagnetic relay and its experimental verification

Hermetically Sealed Electromagnetic Relay(HSER) which used in fields of aviation and aerospace has highly requirement for its thermal characteristics. For the complex working conditions of HSER, efficient and intuitive thermal analysis are needed in the process of optimization design and analysis. In this paper, a basic theoretical model of thermal resistance and heat source is constructed based on the similarity theory of heat-circuit, and the contact heat source model based on the minimum energy principle is constructed. With the dual relationship between temperature rise T of the thermal field in the contact area and the electric field potential φ as the core, the thermal network of a typical HSER is established according to the basic connection relationship of every major part, and the topological analysis is carried out for the thermal network under coil energized and coil de-energized condition respectively, The basic heat transfer path of HSER is derived by comparing the states of connected branches and nodes in the topology. The actual thermal imaging of the measured prototype in coil energized and coil de-energized condition under different working conditions such as rated load and overload is abstracted as the local temperature gradient distribution using a digital image processing method, and compared with the topology analysis data, the correctness of the thermal network model is verified.