To connect a 3-phase motor in a star (or wye) connection, you connect each of the motor’s three windings to a common neutral point. This means that one end of each winding is joined together, creating a central point. The other ends of the windings are connected to the three-phase power supply. In a delta connection, each winding is connected end-to-end to form a closed loop. Specifically, the end of the first winding connects to the start of the second winding, the end of the second winding connects to the start of the third winding, and the end of the third winding connects to the start of the first winding. Each junction point is then connected to one of the three-phase power supply lines.
Not all motors can be connected in both star and delta configurations. The suitability for star or delta connection depends on the motor’s design and its intended operating voltage. Motors designed for dual voltage can usually be connected in star or delta. Typically, motors rated for lower voltage are connected in delta, while motors rated for higher voltage are connected in star. The motor’s nameplate or technical documentation usually indicates the permissible connection methods and the corresponding voltage ratings.
A 3-phase motor can be configured in either delta or star, depending on the application and the supply voltage. When configured in delta, the motor windings are connected in a triangular fashion, which is often used for lower voltage supply. In star configuration, the windings are connected to a common neutral point and typically used for higher voltage supply. Some motors are specifically designed to start in star configuration and then switch to delta during operation to balance starting current and operational efficiency. The choice of configuration can affect the motor’s performance characteristics, such as starting torque and current.