A star-delta starter is a reduced voltage starter for induction motors. It lowers the starting current by first connecting the motor in a star (Y) configuration, then switching to a delta (Δ) configuration for normal operation after a predetermined time. This control requires three contactors: Main Contactor (KM1) – Powers the motor circuit. Star Contactor (KM2) – Configures motor windings in star for starting. Delta Contactor (KM3) – Configures motor windings in delta post-transition. These contactors operate in sequence with a timer to ensure safe and efficient switching between star and delta configurations.