P A = P 0 { 1 + ?? k n cos n ( N r ?? ) } P B = P 0 { 1 + ?? k n cos n ( N r ?? + 2 ?? / 3 ) } P C = P 0 { 1 + ?? k n cos n ( N r ?? + 4 ??3 ) } P _ A = P 0 { 1 + ?? k n cos n ( N r ?? + ?? ) } P _ B = P 0 { 1 + ?? k n cos n ( N r ?? + 2 ?? / 3 + ?? ) } P _ C = P 0 { 1 + ?? k n cos n ( N r ?? + 4 ?? / 3 + ?? ) } } ( 6 ) Here, Fm is a magnetomotive force of magnet, Pm is a permeance of magnet, and