Answer / harish mishra(asst. prof. )

1.In dc generator the rotor is arrmature winding whereas the stator is field winding but in ac generator it is just the reverse.
2. In dc generator the speed is not synchronous i.e., the speed of rotor doesn't attain speed of stator but in casè of synchronous generator the speed of both are linked with each other.

Answer / 7anoter4

Both transform kinetic energy[mechanical energy]of a primer
[D.G. or turbine] into electrical energy. But d.c.generator
will generate direct current and the synchronous generator
generates alternative current.

Both have d.c. supplied poles-d.c.gen. on stator synchron.
on the rotor.

Actually, by rotating the winding in the static magnetic
field as in d.c. gen. or by rotating the poles[that means
the magnetic field] as in synchron. we get alternative
electro-magnetic force[voltage],but in d.c. generator a
collector-or a semiconductor bridge-rectifies the current
and we get d.c. current

Answer / 7anoter4

In three phase system the 3 phases windings are even
distributed along the stator periphery and since the 3
phase currents are 120 electrical degrees in time
distanced one from each other ,then an apparent rotating
magnetic field is installed[as an armature reaction].

The synchronous generator rotor rotates in the same time
with this field [stator itself does not move]. [differently
from the asynchronous[induction] generator in which rotor
velocity is more elevated than this field velocity and the
difference depends on the load.]

In d.c. generator no such rotating field is generated as
the armature reaction is always in d.c. field and it is
rotates with the rotor together[one could say it is
also "synchronous" rotation].

However this field disturbs the collector operation in the
commutation process.

In order to avoid this, commutation auxiliary poles are
located between excitation poles and are supplied by
armature current.

Answer / nilesh

DC GENERATOR IS SINGLE EXCITED AND SYNCRONOUS GENERATOR OR
AC GENERATOR OR ALTERNATOR IS DOUBLE EXCITED.

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