Electrical Machines
Consider the following statements regarding the magnetization characteristics of a dc generator : 1. It represents the variation of field flux with field current. 2. Variation of open-circuit terminal voltage with field current is independent of speed 3. It is non-linear from zero to rated field current 4. It helps to determine the critical field resistance at a given speed 5. It always starts from the origin Which of these statements are correct ?

 1 and 4
 1, 2 and 5
 3 and 5
 2, 3 and 4

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
A 3-φ alternator has negligible stator resistance. A short circuit test is conducted on this alternator. At a particular speed, a field current of If1 is required to drive the rated armature current. If the speed of the alternator is reduced to half, the field current required to maintain rated armature current

 Woud be equal to 2If1.
 Would be equal to If1/2.
  Cannot be predicted due to insufficient data.
 Would be equal to If1.

ANSWER DOWNLOAD EXAMIANS APP