Comparison of three phase induction motor start using DOL, Star Delta and VSD Altivar61

Abstract

In general, induction motors can be operated by connecting the motor directly to the supply circuit or by using a voltage that has been reduced to the motor during the start period. The obstacle of using a 3 phase induction motor is when starting, where the motor requires more current, which is about 5 to 7 times the nominal current, causing the voltage on the system to drop which can interfere with other equipment. In this study the researchers analysed the starting of a 3 phase induction motor using the direct on line system (DOL), star delta, and variable speed drive (VSD) both when the motor is free of charge and when the motor is loaded. Through this research can be seen the difference in the magnitude of current, voltage, power and THD. From the results of observations on the three types of 3 phase induction motor starting methods, it was shown that using a variable speed drive (VSD) altivar61 gave the largest decrease in current when compared to other systems.