Short-Circuit Forces in Symmetrical Windings of Transformers

The position of the windings with regard to the neighbouring iron cannot be neglected in calculations of the acting short-circuit forces. In three-phase as in single-phase core-type transformers with concentric windings one should, in calculating the forces active within the window, not omit to take also into account all currents present within that window, as is shown by the results of a short-circuit test as well as by calculation. The forces per centimeter inside and outside the window are different.

It is stated that in three-phase core-type transformers with concentric windings, if one winding is in Y connection and the neutral is brought out, the impedance test can give an impression of the asymmetry of the windings, by determining either the neutral voltage, or the load losses in…