Why dc voltage used to excite alternator field in stead of ac?

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Why dc voltage used to excite alternator field in stead of ac?..

Answer / sankaranarayanan

field flux produced by dc supply is constant where as in ac
supply will not give a constant field flux

So, alternator output will not constant.

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Why dc voltage used to excite alternator field in stead of ac?..

Answer / kj

When a wire is moved through a magnetic field it produces a
voltage across the wire. To produce an ac output the wire
must move past a north pole and then a south pole in
continuing sequence.
A dc voltage on the field will maintain the poles with the
same polarity. An ac voltage will cause the polarity to
reverse 100 times a second (50Hz) and this will not be
usable for generating the ac output voltage.
Usually an ac voltage is used but it is rectified either as
half wave or full wave before being put into the field.

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Why dc voltage used to excite alternator field in stead of ac?..

Answer / mohamed abd el-raouf

so the magnetic field of the rotor can connect with the magnetic field of the stator

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Why dc voltage used to excite alternator field in stead of ac?..

Answer / haytham hashim

coz dc can be controlled in awide range but cann't be

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