3-13 In the machine shown in Fig. P3-13, the air-gap flux density B, is constant and equal to Bmax in front of the pole faces, and is zero elsewhere. The direction of the B-field is from left ia ell' + @m 60° 60° O PROBLEMS 91 Stator magnetic axis Fig. P3-13 Problem 3-13. (north pole) to the right (south pole). The rotor is rotating at an angular speed of @m, and the length of the rotor is l. Plot the induced emf e₁1 as a function of 0. What should be the wave- form of a that produces an optimum electromagnetic tor- que Tem?

Fig: 1