Electrical Machines
If Pi and Pc represent core and full load copper loss respectively, the maximum KVA delivered to load corresponding to maximum efficiency is equal to rated KVA is

 Pi/Pc
 √(Pi/Pc)
 (Pi/Pc)2
 Pc/Pi

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Electrical Machines
Flashing the field of DC generator means

  creating residual magnetism by a DC source.
  neutralising residual magnetism.
 increasing flux density by adding extra turns of winding.
  making the magnetic losses forces parallel.

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