Surface inspection problems in thermoelectric testing

Abstract

This paper demonstrates the outcome of experimental studies on thermoelectric characteristics of thermocouples. Measurements were carried out using different types of thermocouples; each studied alone then investigated when they are connected in parallel, in order to simulate the imperfect nature of the various multi-contact surface of the tested object. The investigated types were Chromel-Alumel and Nichrome-Constantan. The thermoelectric characteristics were measured at the temperature range 160° − 400° Celsius, in order to identify the best operating temperature for the hot electrode. Furthermore, the load resistance is another important factor that has been investigated and therefore varied from 1Ω to 10kΩ, in order to determine its effect on the electrical characteristics of thermocouples. Accordingly, these characteristics will help defining the requirements for an optimum thermoelectric testing.