Electrical Machines
A 500 V, 55 kVA single phase alternator has an effective resistance of 0.5 Ω. An excitation current of 10 A produces 200 A armature current on short circuit and an emf of 450 V on per circuit. The synchronous reactance will be

 2.781 Ω.
  2.241 Ω.
 25.564 Ω.
 2.74 Ω.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
A DC shunt generator builds up to a voltage of 220 V at no load while running at its rated speed. If the speed of the generator is raised by 25% kepping the circuit conditions unaltered, then the Voltage to which the machine would build up will

 increase to value lying between 220 V and 1.25 times 220 V
 not change and remain at 220 V
 increase to 1.25 times 220 V
 increase to a value greater than 1.25 times 220 V

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
Which of the following represents the commutator pitch?

 Number of conductors spanned by one coil at the back end of the armature.
 Number of commutator segments between two successive coils.
 The distance between the staring of first coil and its next successive coil
 Number of conductors spanned by one coil at the front end of the armature.

ANSWER DOWNLOAD EXAMIANS APP