This starting process can only be used in an electric motor in which the two ends of each of the three stator windings are connected to the terminal board. On the other hand, the winding Gates A25 must be done in such a way that the triangle connection corresponds to the mains voltage, as for example for a three-phase 380 V network, a motor winding at 380 V triangle and 660 V star is required.
The principle of this departure is to start the motor by connecting the star windings to the mains voltage, which is the same as dividing the star motor voltage by Ö3 (in the example given above, the mains voltage 380 V = 660 V / Ö3). The starting current peak will be divided by 3: Ia = 1.5 to 2.6 I direct start.
Indeed, a star-rated 380 V / 660 V motor at rated voltage of 660 V absorbs a current Ö3 times lower than in a triangle connection at 380 V. As the star connection is made at 380 V, the current is likewise divided by 3, then in total, by 3.