Electrical Machines
Consider the following statements : For a level compounded dc generator to run at constant voltage, the series field mmf must effectively compensate 1. armature reaction mmf 2.armature resistance drop 3. brush contact voltage drop Which of these statements is/are correct ?

 1 and 3
 2 alone
 1 and 2
 1, 2 and 3

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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 magnitude will both increase.
 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 of current will decrease but the power factor will increase.

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