Analiza zagrevanja bakarnih provodnika sa strujom

Abstract

The method for the temperature measurement on the surface of three copper conductors, with cross-sections of 4 mm2 , 6 mm2 i 10 mm2 , are presented in this paper. After the determination of temperature probe, the series of temperature measurements are performed on chosen wire conductors. The first two series are performed applying DC generator, in two different cases: when, during the measurement the voltage on the conductor’s end was held constant and the current inside the conductor was held constant. After that, the temperature measurements on the conductor’s surface were performed supplying conductors with AC, time harmonic currents, again in two particular cases: constant RMS voltage value on the conductor’s ends and constant RMS value of current inside the conductor. The measuring results were expected for all four cases and for all thee conductors. Due to presence of skin effect, the Joule’s losses were higher in the AC cases, meaning that the temperature increase was faster and that the final reached temperature, for the same values of voltage or currents, was higher. It was also demonstrated that the higher Joule’s losses appeared when the current was kept constant during the measurements, in both DC and AC supplying. The measurements were performed with the instrument which enabled the results recording on USB stick; hence the measurements duration was 30 minutes, recording result every two seconds. The measuring results were presented graphically, together with graphical presentation of the comparison between methods and the results for all investigated conductors.