Electrical Machines
A 3 - Φ induction motor draws an current of 50 A from mains when starts by direct switching. If an auto transformer with 60 % tapping is used for starting the current drawn from the mains will be

 36.
 50.
 80.
  18.

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Electrical Machines
If the frequency of input voltage of a transformer is increased keeping the magnitude of voltage unchanged, then

 Pe will increase but Ph will decrease
 Ph will increase but Pe will decrease
 both hysteresis loss(Ph) and eddy current loss(Pe) will increase
 Ph will decrease but Pe will remain same

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Electrical Machines
A DC shunt generator builds up to a voltage of 220 V at no load while running at its rated speed. If the speed of the generator is raised by 25% kepping the circuit conditions unaltered, then the Voltage to which the machine would build up will

 increase to value lying between 220 V and 1.25 times 220 V
 increase to 1.25 times 220 V
 not change and remain at 220 V
 increase to a value greater than 1.25 times 220 V

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