Electrical Machines
A transformer core is made up of a silicon steel laminations which has maximum flux density 1 Tesla. If it was cold rolled grain oriented its flux density increases to 1.6 Tesla. What is the saving in core size or area due to cold rolled grain oriented process?

 60%
 68%
 38%
 40%

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Electrical Machines
If the applied voltage of a certain transformer is increased by 50% and the frequency is reduced by 50%, the maximum flux density will (assuming that the magnetic circuit remains unsaturated)

 changes to 0.5 times the original value
 remain the same as the original
 changes to 1.5 times the original value
 changes to three times the original value

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Electrical Machines
Two DC generators having equal open-circuit emfs but slight different load characteristics are operating in parallel, then

  the machine will share load equally.
 the machine with more drooping characteristic will supply more load.
None of these
  the machine with more drooping characteristic will supply less load.

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