Stand experimental pentru studiul impactului ac?ion?rilor electrice moderne asupra motoarelor asincroneExperimental Stand for Studying the Impact of Modern Electrical Drives on Asynchronous MotorsFull text in Romanian

摘要

Asynchronous motors are present in more than 70 % of the industry applications, being used in almost all water recirculation loops and in air ventilation systems. Many of them were specially designed for these processes and currently have more than 30 years of continuous operation, thanks to their proven reliability and their recirculation system’s dependence to drive at specific operating parameters. The evolution of technology has allowed the industry to use them in a wider frame by varying the nominal speed according to the supply voltage frequency, although they were designed to be driven at constant speed. The worldwide energy efficiency programme based on energy reduction has been promoted this concept in the past years and as a consequence almost all processes where variable flow is needed have the above-mentioned ensemble as a default electrical drive. Starting from this context, a couple of important questions have arisen: what is the impact of this transformation on the quality of the voltage and current at the motor terminals? Furthermore, is it harmful for the motor normal functionality? Could this technology shorten its lifetime operation or/ and affect any other surrounding equipment. To be able to answer these questions and observe these conditions an experimental setup must be build and put into action. Thus, in this paper an experimental stand for studying the impact of modern electrical drives on three phase asynchronous motors is presented. For analysing the parameters state-of-the-art measurement equipment is used. The results obtained by a series of measurements prove that using a static frequency converter to supply a motor at nominal frequency of 50Hz, and also below and above this set point, generates a level of harmonics, more accentuated in the current sinusoidal waveform. These perturbations can generate motor to overheat and impair his lifespan during time.