A comparative study on the impact of various starting methods for three-phase squirrel cage induction motors

Abstract

Induction motors are among the most commonly used electric motors due to their reliability, durability, and cost-effectiveness. They are widely employed in both household and industrial applications, owing to their high torque-to-volume ratio, robustness, and low maintenance requirements. However, during the starting phase, induction motors draw a high inrush current, which affects the electromagnetic torque, speed, and current. Traditional starting methods, such as Direct On-Line (DOL), Star-Delta (SD), and Auto-Transformer (AT) starters, are employed to control these parameters within certain limits. This study compares the starting methods of three-phase squirrel cage induction motors, using DOL which has a starting time of 0.5-3 seconds, SD with a starting period of 2-10 seconds, and AT starters with a starting period of 3-10 seconds. The squirrel cage induction motor is known for its unique challenge of high initial inrush current. The research utilized an experimental approach, where laboratory tests were conducted to assess the performance of the aforementioned starting methods. The study employed MATLAB Simulink to observe the output behavior. The results, presented in tables and bar charts, compare various machine parameters such as voltage, current, speed, and torque. The findings indicate that induction motors experience significant starting current, and the implementation of a starting controller in phase with the stator winding during startup can help to control the initial inrush current.