Indirect Thermographic Measurement of the Contact Temperature of an Electromechanical Relay

Abstract

The temperature of an electromechanical relay is related to the value of the contact resistance. The value of the contact resistance depends, among other things, on the degree of wear and oxidation of the contacts. A too high temperature of the relay contacts leads to their further degradation and an increase in contact resistance. For this reason, monitoring this value is important. In this paper, monitoring of the contact temperature of an electromechanical relay using indirect thermographic temperature measurement is proposed. This approach consists of two parts: the first part is based on thermographic measurement of the relay case, and the second part estimates the contact temperature based on the relationship between the case temperature (measured by a thermal camera) and the contact temperature. The finite element method (FEM) was used in the second part. The results obtained using this method were validated through comparison with experimental measurements acquired by an alternative method.