Electrical Machines
In dc machines, the armature windings are placed on the rotor because of the necessity for

 electromechanical energy conversion
 generation of voltage
 commutation
 development of torque

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

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Electrical Machines
Short circuit test is performed on a transformer with a certain impressed voltage at rated frequency. If the short circuit test is now performed with the same magnitude of impressed voltage, but at frequency higher than the rated frequency then

 The magnetude of current will increase, but power factor will decrease.
 The magnitude of circuit as well as the power factor will decrease.
 The magnitude will both increase.
 The magnitude of current will decrease but the power factor will increase.

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