Electrical Machines
Induction motors normally use cast aluminium rotor because aluminium is

  cheaper in cost.
  of low resistivity.
  easy to cast owing to its low melting point and is easily available.
  lighter in weight.

ANSWER DOWNLOAD EXAMIANS APP

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

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
In a synchronous generator with constant steam input supplies power to an infinite bus at a lagging power factor. If the excitation is increased

 both power angle and power factor increase
 power angle decrease and power factor increase
 power angle increase and power factor decrease
 both power angle and power factor decrease

ANSWER DOWNLOAD EXAMIANS APP