Correlation of Forced and Free Oscillations of Coils and Windings

This paper shows that there exists a simple relationship between the forced and free oscillations of coils and windings which are generally treated in the literature as two separate phenomena. As a consequence, a correlation also exists between certain natural frequencies of a coil or winding under different terminal conditions. Experimental measurements on air coils, iron-core coils, and transformer windings prove the correctness of the theory. The frequencies are determined analytically by energy methods.