ESTIMATING THE EFFECTS OF HARMONIC VOLTAGE FLUCTUATIONS ON THE TEMPERATURE RISE OF SQUIRREL-CAGE MOTORS

This article presents a preliminary analysis of the effect of randomly varying harmonic voltages on the temperature rise of squirrel-cage motors. The stochastic process of random variations of harmonic voltages is defined by means of simple statistics (mean, standard deviation, type of distribution). Computational models based on a first order approximation of the motor losses and on the Monte Carlo method yield results which prove that equipment with large thermal time-constant is capable of withstanding for a short period of time larger distortions than THD = 5%.