The four stator conductors (A, A', B and B') of a rotating machine are carrying DC currents of the same value, the directions of which are shown in the figure (i). The rotor coils a-a' and b-b' are formed by connecting the back ends of conductors ‘a’ and ‘a'’ and ‘b’ and ‘b'’, respectively, as shown in figure (ii). The e.m.f. induced in coil a-a' and coil b-b' are denoted by Ea-a' and Eb-b', respectively. If the rotor is rotated at uniform angular speed ω rad/s in the clockwise direction then which of the following correctly describes the Ea-a' and Eb-b' ?
figure (i): cross-sectional view figure (ii): rotor winding connection diagram
1
Ea-a' and Eb-b' have finite magnitudes and are in the same phase
2
Ea-a' and Eb-b' have finite magnitudes with Eb-b' leading Ea-a'
3
Ea-a' and Eb-b' have finite magnitudes with Ea-a' leading Eb-b'
4
Ea-a' = Eb-b' = 0
5
None of these