The Thermostructural Analysis of Electric Contacts Using a Finite Element Model

The thermostructural behavior of arcing electric contacts used in motor controllers, subjected to overcurrent, were investigated, using the finite element (FE) method. An axisymmetric model, representative of a silver contact brazed to a carrier strip, was constructed to conduct transient heat transfer analyses for determining temperature and thermal stress distributions. The analyses included the temperature dependency of both the thermodynamic and mechanical properties, including latent heat effect due to phase change if localized melting occurred from arc heating. Attention was focused on the stress distribution generated in the brazed joint since some failures are known to originate at that site.