Electrical Machines
A 2 pole synchronous machine is operating at 3000 rpm. Find the relation between electrical angular momentum (ωe) and mechanical angular momentum (ωm) ?

 ωe = 2*ωm
 ωe = 1/2*ωm
 ωe = ωm
 ωe = 4*ωm

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Electrical Machines
In DC machines, the interpoles are provided

 to counteract the reactance voltage and the cross-magnetizi
 to counteract demagnetizing effect of armature mmf in commutating zone.
  both (B) and (C).
  to make commutation spark less.

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Electrical Machines
Short circuit test is performed on a transformer with a certain impressed voltage at rated frequency. If the short circuit test is now performed with the same magnitude of impressed voltage, but at frequency higher than the rated frequency then

 The magnitude of current will decrease but the power factor will increase.
 The magnitude of circuit as well as the power factor will decrease.
 The magnitude will both increase.
 The magnetude of current will increase, but power factor will decrease.

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