Electrical Machines
Two 3-phase AC generators are such that one has twice the linear dimensions of the other. The field windings of each are excited to give identical sinusoidal air-gap flux density waveform. Both have the same number of stator slots and identical winding patterns. The conductor/slot in a big generator is K times that of the smaller one. The value of K to get equal no load voltage at same frequency is

 1/4.
 8.
 4.
  1/2.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
Commutation in a DC machine may be explained as a process

  by which electric current in a coil is reversed.
  in which magnetic field is set up.
 by virtue of which emf is induced in the armature conductors.
 how alternate flux affects the main field flux.

ANSWER DOWNLOAD EXAMIANS APP