Thermal field simulation analysis of miniature DC electromagnetic relays

The thermal-electric analysis model of a miniature DC electromagnetic relay is worked out with the software ANSYS. The heat generation by coil and contact circuit is considered, in which the contact area of the contacts is treated as an equivalent small cylinder with the same resistance as the contact resistance. Meanwhile, thermal effects of connected wires are equivalently reduced to the heat generator according to its heat flux. Heat conductivity, convention and radiation are all taken into account in the thermal analysis, in which the coefficients of heat conductivity and convention are considered as variables of temperature. With the above model, steady thermal analysis is performed for the DC electromagnetic relays with and without shell under different coil voltage. The temperature fields of every part of the relays are obtained. And the average temperature rises of the coil are calculated according the FEA results and in good agreement with the experiment results by comparison.