MM0704, Lesson 4
Lt = L1 + L2 + 2M
Lt = 16 + 4 + (2 X 6)
Lt = 32 h
If you reverse the connections of one of the coils as shown in figure 4-11, the fields will have a canceling effect. The
formula for total inductance in that case is:
Lt = L1 + L2 - 2M.
To the illustrative example, this would change our total inductance between A and B from 32 h to:
Lt = 16 + 4 - (2 X 6)
Lt = 8 h.
Figure 4-11. Canceling the Effect of Mutual Inductance.
Another factor affecting coupling is the angle at which the flux of one coil cuts that of another coil. If you pivot L2
(figure 4-12) at the center, you will find that the M reduces to zero at 90 and actually subtract from the total
Figure 4-12. Angle Affect on Coupling.