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

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

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Electrical Machines
Torque angle of a synchorous machine operating from a constant voltage bus is usually defined as the space angle between

  Rotor mmf wave and stator mmf wave.
 Stator mmf wave and resultant flux density.
 Stator mmf wave and resultant mmf wave.
 Rotor mmf wave and resultant flux density wave.

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

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