N 1, N 2, and N 3 are the number of turns in the three primary windings. N 4, N 5, and N 6 are the number of turns in the three secondary windings. Φ 1, Φ 2, and Φ 3 are the fluxes in the three vertical elements. Magnetic flux in each permeance element in webers is numerically equal to the charge in the associate capacitance in coulombs. The energy in each permeance element is the same as the energy in the associated capacitor.