Star Delta Starter for Three Phase Induction Motor

Abstract

We all know that three phase induction motors draw a lot of electricity when they first start up, compared to when they are not running at full load. Various methods for beginning these induction motors with low current values have been developed through time to lessen the impacts of high starting current, and the sophisticated starting methods to lower starting current are typically compromised with other factors. unexpected inrush currents caused by the beginning system itself This project uses relays and an electronic timer to provide a low-current start to the motor while also protecting it from inrush currents. In 50 Hz industrial motors, the most popular low voltage starters are star or delta starts. They're utilized to try to cut down on the amount of current used to start the engine. Three contactors, a timer, and a thermal overload are used in the Star/Delta starter to operate a three-phase motor at 440 volts at 50 Hz from an AC mains supply. A motor must be in the delta linked position during a normal run to utilize the Star Delta Starter, and the major purpose is to be able to use the starter. Because all the rotor bars are joined together to form a closed channel when the motor is at idle, it acts like a short-circuited transformer on the secondary side. The rotor bars will be subjected to a considerable current flow as a result of this. As a result, when the motor is turned on, the stator draws a large current, 8-10 times the rated current. As a result, before starting the motor, the voltage applied to it must be reduced. The current in a Star connection is split into three phases, yet the line voltage is three times the phase voltage. When a motor is started in a star connection, the voltage is dropped, resulting in a reduction in current. When we operate the motor in a delta connection, the voltage is the same as the phase voltage, hence full voltage is applied. Three contactors, a pneumatic timer, and a thermal overload relay or circuit breaker are used to make a Star/Delta Starter for a three-phase motor with a 440-volt AC main supply at 50 Hz.

Keywords: Star delta starter, MCB, contactors, overload relay, timer