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)

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

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Electrical Machines
Due to magnetic saturation, the flux per pole in a DC machine without brush shift

  decreases in both generators and the motors with load.
 increases in both the generators and the motors with load.
 decreases in generators and increases in motor with load.
 increases in generators but decreases in motor with load.

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