In the triangular connection, a set of coils of the motor bears a voltage of 380V V. In the star connection, the motor bears 380V with two sets of coils, so the voltage is still 380 V, but the number of coils of the motor is increased. Generally, connections below 3KW are star connections, and connections above 3KW are triangle connections. The motor with high power adopts star delta starting to reduce the impact on power grid and equipment. All the above were written by Shangyu Dongxing himself. . . . The following is network replication, you can learn more about it.

The star angle step-down starting of the motor means that when the motor is running normally, the windings of the coil are connected in a triangle shape. When the motor is running, the voltage borne by each phase winding is line voltage, that is, 380V voltage. In order to reduce the starting current of the motor, when the motor starts, the windings are connected in a star shape through contactors. At this time, the voltage borne by each phase winding is phase voltage, that is, 220V voltage, which is small, so the current is also reduced. It reduces the root sign of the original current by one third to achieve the purpose of reducing the starting current. Its advantage is that it reduces the impact of the motor on the system due to large starting current, and is suitable for systems with relatively small power supply capacity. In addition, it can reduce mechanical impact. However, due to the reduction of voltage, the starting torque of the motor is reduced by three times, which is its shortcoming, but it can meet the mechanical requirements in mechanical equipment with low starting torque requirements. When the motor reaches or approaches the rated speed, it is connected by a star through a contactor, converted into a triangle, and starts to move at the rated voltage. Of course, if the power grid allows or the starting torque is large, it can also be started directly.