One of the reasons why Star-Delta starters are used is because of the lower starting current flow in the Star connection stage, which provides less starting torque and puts less mechanical and electrical stress on the system, thereby increasing its lifespan.

In star wiring, the three winding phases of the motor are combined to form the so-called star point. With a power supply voltage of 400 V, the phase voltage (voltage between the line conductors) of 230 V each. In delta wiring, the ends of the three winding phases are combined and connected to the individual phases.

3-phase motors use coils of wire to create magnetic fields and produce rotation. Standard Three-phase motors use six individual coils, 2 for each phase. The internal construction and connection of these coils inside of the motor are predetermined when the motor was manufactured.

Usually, Star Connection is used in both transmission and distribution networks (with either single-phase supply or 3-phase. Delta Connection was generally used in distribution networks. Since the insulation required is less, Star Connection can be used for long distances.

Star Connections are mainly required for the Power supply Transmission Network for longer distances, whereas Delta connections are mainly in Distribution networks and are used for shorter distances. In Star Connection, each winding receives 230 V, and in Delta Connection, each winding receives 415 V.