Electrical Machines
A transformer has resistance and reactance in per unit as 0.01 and 0.04 respectively. Its voltage regulation for 0.8 power factor lagging and leading will be

 3.2% and -1.6%
None of these
 6% and -4%
 4.8% and -3.2%

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Electrical Machines
The residual magnetism of a self-excited dc generator is lost. To build up its emf again

 the armature connection must be reversed
 the field winding must be replaced
 field winding must be excited by low voltage dc supply
 the field winding connection must be reversed

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Electrical Machines
The damper windings also called the squirrel cage windings or damper grids

  consists of short-circuited copper bars embedded in the field pole faces.
  are provided on the stator for improving power factor.
  are provided in a synchronous motor to make it self starting.
  both (A) and (B).

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