It is shown that the method can be used to obtain the equilibrium configuration which is induced by non-symmetrical current, and to solve the non-convergence problem of a free boundary equilibrium.

With symmetry of branch impedance matrix in reciprocity network the loop current equation that the loop impedance matrix is symmetrical is presented.

Equivalent current method different from symmetrical component method and revolving field method, is used for performance calculation on capacitor single phase motors on this paper.