Why is the star-connected voltage of the motor 660 volts?

The star connection results in a voltage drop compared to the delta connection; based on the principles of star and delta connections, this voltage drop is 1.732 times greater. Therefore, 380V * 1.732 = 658V (660V). A voltage of 660V ensures that each coil also has a voltage of 380V in the star connection.

So if my motor is connected in star configuration, is the voltage between any two taps 660V when it is operating normally? Is it this? Do you understand? So what exactly is Star Angle startup? I’m a bit confused; I just graduated and would appreciate some advice from those who are more experienced!

Reply to 3# dcl2030: Motor coils are generally divided into 3 groups, with a total of 6 taps. In a triangular connection, the ends are connected to each other, and the power supply is connected to these three terminals; the voltage between any two of these terminals is equal to the supply voltage, which is usually 380V in China. In the star connection, one terminal from each group is connected together, while the power supply is connected to the other three separate terminals. The voltage between these three terminals to which the power supply is connected is, of course, the supply voltage itself; however, the voltage between any one of these three terminals and the terminals that are connected together is 1/1.732 times the supply voltage. Regarding the 660/380 V motors mentioned by the poster, if the power supply is 380 V, it is recommended to connect them in a delta configuration; otherwise, the rated power will not be achieved. If the power supply is 660 V, a delta connection should also be used, otherwise the motor may get damaged