3 phase motor star delta
A 3 phase motor star delta starter is a sophisticated starting mechanism designed to reduce the initial starting current and torque in three-phase induction motors. This system operates by initially connecting the motor windings in a star configuration during startup, which effectively reduces the voltage across each winding to 58% of the line voltage. After the motor reaches approximately 80% of its rated speed, the connection automatically switches to delta configuration, allowing the motor to operate at full voltage and deliver maximum torque. This method is particularly beneficial for high-power motors where direct-on-line starting would cause excessive current draw and potential damage to both the motor and power supply system. The star delta starter consists of three main contactors, an overload relay, and a timer that controls the transition from star to delta connection. This configuration is widely used in industrial applications such as conveyor systems, pumps, compressors, and heavy machinery where controlled starting is essential for equipment longevity and power system stability.