Determine the equivalent inductance:
Two coils of inductances 4H and 6H are connected in parallel. If their mutual inductance is 3 H, determine the equivalent inductance of the combination if (i) mutual inductance assists the self-inductance, and (ii) mutual inductance opposes the self-inductance.
Solution
L1 = 4 H L2 = 6 H M = 3 H
L (di/dt ) = (L1 L2 - M2 )/ (L1 + L2 + 2M) di/dt = 4 × 6 - 32 /4 + 6 - 2 × 3= 3.75 H
L = (L1 L2 - M2)/ (L1 + L2 +2M) = 4 × 6 - 32 /4 + 6 + 2 × 3 = 0.9375 H