A twocoil system is shown in figure The reluctances of the t

A two-coil system is shown in figure. The reluctances of the two air-gaps are R_1 = 20K A/w band R_2 = 30K A/wb, and the core permeability mu_r rightarrow infinity. Suppose that N_1 = 180 and N2 = 120. Determine the self-inductances L_1 and L_2, and mutual-inductance M; If i_1 = 2sin20t A., and coil #2 is open, find the induced voltage If now i_1 = 1 A., and coil #2 is open, determine the energy W_1 stored in air-gap # 1 and W_2 stored in air-gap #2.

Solution

The changing magnetic field created by one circuit (the primary) can induce a changing voltage and/or current in a second circuit (the secondary). The mutual inductance, M, of two circuits describes the size of the voltage in the secondary induced by changes in the current of the primary: change in I (primary) V(secondary) = - M * ---------------------- change in time The units of mutual inductance are henry, abbreviated \"H\". A circuit can create changing magnetic flux through itself, which can induce an opposing voltage in itself. The size of that opposing voltage is change in I V(opposing) = - L * ------------- change in time where L is the self-inductance of the circuit, again measured in henries.