Here is a portion extracted from a book Design of Rotating Electrical Machine.


I have a doubt about the current linkage, Θf, in figure 2.2b of a salient pole motor. In this textbook, the current linkage is expressed by ∫H⋅dl = Θf = ∑i. However, in the figure 2.2b between q(left) and q(right), how can the Θf be constant? Since, the author doesn't show how he chose the Amperian loop, how can I know how many currents are enclosed (∑i)?