Electrical Machines
The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be

 88.8%.
 48.0%.
 57.1%.
 59.2%.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
The result of slip test on a 3-phase, 20 KVA, 400 V, 50 Hz connected salient pole alternator is given below- Phase value: Vmax = 100 V, Vmin = 96 V, Imax = 10 A and I min = 7 A. The direct and quadranature axis reactances are respectively

 8.248 and 5.54 Ω.
 14.28 and 9.60 Ω.
  14.28 and 5.54 Ω.
 8.248 and 9.60 Ω.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
The compensating winding in a DC machine

  is located on pole shoes to avoid the sparking at the brushes.
 is located in armature slots for compensation of the armature reaction.
 is located on commutating poles for improving commutation.
  is located on pole shoes for avoiding the flashover at the commutator.

ANSWER DOWNLOAD EXAMIANS APP
MORE MCQ ON Electrical Machines