For a large level of generation rotating field alternators are used. There is an advantage of rotating field alternator over rotating armature alternator. The advantage of having stationary armature winding is that
the voltage can be directly connected to load and also we can insulate the conductor
.
Why is rotating field system used in preference to Fieldary field?
Because you would have to draw all the power via slip rings and brush-gear and one could not generate at say 11 kV. That is why a rotating DC field is preferred and why the stator is able to generate at very high voltage levels as
the insulation issues are much easier to handle
.
What are the advantages of placing field winding on rotor and armature winding on stator in syn machine?
- More Economical: It is more economical to provide Armature winding on Stator and Field winding on rotor. …
- Better Insulation: …
- Better Cooling: …
- More Power Output: …
- More Armature Tooth Strength:
Why rotating field system is used in synchronous machines?
The following are the principal advantages of the rotating field system type construction of Synchronous machines: ·
The relatively small amount of power, about 2%, required for field system via slip-rings and brushes
. … It is easy to provide cooling arrangement for a stationary system of conductors.
What is the advantage of rotating magnetic field?
Advantages of Rotating Field with Stationary Armature
Rotating field is
comparatively light and can run with high speed
. High voltage can be generate due to high speed and there is very little difficulty in providing high voltage on a stationary part than a moving part.
How does a rotating magnetic field work?
The rotor has a constant magnetic field. The north pole of the rotor will move toward the south pole of the magnetic field of the stator, and vice versa. This magnetomechanical attraction creates a force that will drive the rotor to follow the
rotating
magnetic field in a synchronous manner.
How is rotating magnetic field created?
The rotating magnetic field is produced by
the three-phase current of the stator in the actual three-phase induction motor
. … The three-phase windings of the inner stator are spaced 120° electrical degrees apart. In addition, the conductor of each winding is distributed such as a sinusoidal wave.
Why armature is stationary and field is rotating?
In most generators, the
field magnet is rotating
, and is part of the rotor, while the armature is stationary, and is part of the stator. Both motors and generators can be built either with a stationary armature and a rotating field or a rotating armature and a stationary field.
What are the advantages of rotating field over rotating armature?
A
cooling arrangement can be easy for
the high voltage side if it is kept stationary. Inertia is low because a low dc voltage is given to the rotor side. The armature is kept as stationary so that the larger current can collect easily. Cost of the system is low as compared to the rotating armature type.
Why field winding of 3 phase alternator is rotating and armature winding is stationary?
The field poles are placed on the stationary part of the machine. Since no commutator is required in an alternator, it is usually
more convenient and advantageous to
place the field winding on the rotating part (i.e., rotor) and armature winding on the stationary part (i.e., stator).
What will happen when any winding is placed in rotating field?
As the rotor windings cut through the rotating field,
current is induced in them
. This induced current creates a field that, in turn, cuts through the stator windings to create power output to the load. The induction generator thus draws its excitation from the power system to which it’s connected.
What is damper winding?
:
a short-circuited squirrel-cage winding placed in the pole faces and around the pole shoes of synchronous machines
, the currents induced in the winding by the periodic variations in synchronous speed having the effect of a damper. — called also amortisseur.
Why short pitch coil is used in alternator?
Short pitch winding
improves the waveform of generated emf
i.e. generated emf can be made to approximate to a sine wave more easily and the distorting harmonics can be reduced or totally eliminated.
Why EMF method is called pessimistic method?
In EMF method, the voltage drop due to armature resistance (R
a
) and the drop due to synchronous reactance(X
S
) is considered, both the drops are emf quantities. … This method is also called pessimistic method, because
the voltage regulation obtained by this method is more than the actual value
.
What are V and inverted V curves of synchronous motor?
What is V Curve and inverted v curve? The graphical representation of armature current Ia vs field current If is called V-curve since the final view looks like English letter V. At the same
time the power factor vs field current
is called inverted V-curve of a synchronous motor.
What do you mean by synchronous condenser?
In electrical engineering, a synchronous condenser (sometimes called a synchronous capacitor or synchronous compensator) is
a DC-excited synchronous motor, whose shaft is not connected to anything but spins freely
. … Synchronous condensers are an alternative to capacitor banks for power-factor correction in power grids.
