Desain Pengasutan Motor Induksi 3 Fasa dengan Metode Direct On-Line (DOL), Variable Frequency Drive (VFD), Soft Starting, dan Auto Transformer (Studi Kasus : PT. Indonesia Asahan Aluminium)

Abstract

The 3-phase induction motor is the most widely used drive component in the industrial world. The problem that exists in induction motors is that when starting the motor, the motor starting current can reach five times to seven times the nominal current. The phenomenon of soaring starting currents when starting an induction motor can result in a voltage drop in the voltage supply, the cause of the high starting current in the motor because the electric motor requires a large initial torque in order to fight the inertia of its load in a state of rest. This study aims to compare the slip, starting current, bus voltage, acceleration torque, motor torque, energy savings, and kVAR of Direct On-Line (DOL), Variable Frequency Drive (VFD), soft starting, and auto transformer starting methods. The results of this study were obtained through motor starting simulations in ETAP 19.0.1 software. It was found that the fastest VFD slip reached a steady state at 11+ seconds, the largest starting current was owned by the DOL method which was > 500% FLA in the first 2 seconds, the lowest starting current was owned by the VFD method which was < 20% FLA in the first 2 seconds, the lowest bus voltage drop in the steady state was experienced by the VFD method which was 0.8152%, The fastest acceleration torque reaches steady state in the VFD method at 11+ seconds while the longest reaches steady state in the soft starting method at 59+ seconds, the largest starting torque is owned by the VFD method which is 218.1% and the lowest is owned by the soft starting method which is 20.75%, the largest energy savings are owned by the soft starting method which is 148.02 kW, the largest reactive power (kVAR) is owned by the DOL method which is worth 704.19 kVAR. From several observed variables, the best starting method is the Variable Frequency Drive (VFD) method.