A Star Delta Starter is an electrical control circuit used to start and control the speed of three-phase electric motors. It is also known as a Wye-Delta Starter or a Reduced Voltage Starter.
The Star Delta Starter consists of three contactors, a timer, and an overload relay. The contactors are used to switch the motor windings from a star configuration, which is a lower voltage and higher current configuration, to a delta configuration, which is a higher voltage and lower current configuration. The timer is used to control the switching time between the star and delta configurations, while the overload relay protects the motor from overloading.
When the motor is started, the contactors are in the star configuration, which limits the starting current and reduces the voltage applied to the motor. This reduces the stress on the motor windings and reduces the starting torque. After a preset time, the contactors switch to the delta configuration, which applies full voltage to the motor and provides full torque.
The Star Delta Starter is commonly used in applications where the starting current of the motor is high, such as in industrial machinery and heavy-duty equipment. It allows for a smooth and safe start of the motor while protecting it from damage due to high starting current.