GATE EE 2014 Question Paper (02-Mar-2014) (Shift 1)

A 250 V dc shunt machine has armature circuit resistance of 0.6 Ω and field circuit resistance of 125 Ω. The machine is connected to 250 V supply mains. The motor is operated as a generator and then as a motor separately. The line current of the machine in both the cases is 50 A. The ratio of the speed as a generator to the speed as a motor is _______

A three-phase slip-ring induction motor, provided with a commutator winding, is shown in the figure. The motor rotates in clockwise direction when the rotor windings are closed.



If the rotor winding is open circuited and the system is made to run at rotational speed fᵣ with the help of prime-mover in anti-clockwise direction, then the frequency of voltage across slip ring is f₁ and frequency of voltage across commutator brushes is f₂. The values of f₁ and f₂ respectively are

A 20-pole alternator is having 180 identical stator slots with 6 conductors in each slot. All the coils of a phase are in series. If the coils are connected to realize single-phase winding, the generator voltage is V₁. If the coils are reconnected to realize three-phase star-connected winding, the generated phase voltage is V₂. Assuming full pitch, single-layer winding, the ratio V₁/V₂ is

For a single phase, two winding transformer, the supply frequency and voltage are both increased by 10%. The percentage changes in the hysteresis loss and eddy current loss, respectively, are

A synchronous generator is connected to an infinite bus with excitation voltage E${}_f$ = 1.3 pu. The generator has a synchronous reactance of 1.1 pu and is delivering real power (P) of 0.6 pu to the bus. Assume the infinite bus voltage to be 1.0 pu. Neglect stator resistance. The reactive power (Q) in pu supplied by the generator to the bus under this condition is___________.