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Where does the voltage that is necessary for field excitation on the rotor originates from?
The excitation current is provided by a small self-excited pilot generator, attached to the same shaft as the alternator's rotor.
What is excitation and why is it needed for start up in an AC generator?
An alternator is just another name for a synchronous generator. Excitation is needed to create a magnetic field in the rotor. When to rotor is spun with excitation the magnetic field will cut through the stator field and produce an AC voltage in the stator field. In terms of an alternator with built in rectifier the stators AC voltage in the rectified to DC. The strength of excitation will determine the alternators output voltage. The AVR Automatic Voltage Regulator built into almost every alternator controls field current to maintain a constant output voltage.
What is exciter in electrical?
An exciter in electrical engineering refers to a device that provides the necessary excitation current to the field winding of a synchronous machine, such as a generator. This excitation current is essential for establishing the magnetic field required for the generator to produce electrical power. Exciters can be either rotating (mounted on the same shaft as the generator) or static (using solid-state technology), and they play a critical role in regulating the output voltage and stability of the generator.
How residual magnetism present inside the self excited generator?
Residual magnetism in a self-excited generator refers to the small amount of magnetism that remains in the magnetic core after the generator has been de-energized. This residual magnetism is crucial for the initial excitation of the generator because it provides the necessary magnetic field to induce voltage when the generator is started. As the rotor turns, the residual magnetism induces a small voltage in the stator windings, which, when connected to the field windings, enhances the magnetic field and leads to self-excitation, allowing the generator to generate power. Without sufficient residual magnetism, the generator may fail to start or produce voltage.
What is meant by the term excertation current when refering to generator?
Excitation current in a generator refers to the current supplied to the rotor windings to create a magnetic field necessary for generating electricity. This current is crucial for controlling the voltage output and overall performance of the generator. By adjusting the excitation current, operators can regulate the generator's voltage and ensure stable operation under varying load conditions.
Generator excitation voltage?
the voltage which is given for creating magnetic field in a generator is known as excitation voltage.
Which relay is used to detect the loss of excitation in generator?
A loss of field relay.
What is the difference between generator over excitation versus under excitation when attached to the grid?
Over Excitation is a condition when the Excitation System is providing too much field current and as a result, the rotor of the generator will over heat. The Excitation System is equipped with an Over Excitation Limiter. This limiter acts to reduce the Excitation Current if this condition exists Underexcitation is a condition when the generator is not getting enough Excitation Current. If the generator does not get enough Excitation Current, it can be un-synchronized with the grid. We call this slipping a pole. If this occurs, the generator can be severely damaged. Kelly Thompson Engineering Lead Siemens Energy Alpharetta GA
Answering Which one is a separately excited generator - ac generator or dc generator?
Excitation is the phenomenon by which you control the excitation of field winding of a generator. In DC generator field winding is placed on stator and this field winding can be self excited or seperately excited depending upon the type on generator used. AC generators can also be self excited or seperately excited type but field winding is placed on rotor nad armature winding on stator.
What voltage is generally used for field excitation?
For a small generator like the 125 Watt Alternator/Generator in your car, 12 Volts at a couple Amps. For a large 1,200,000,000 Power Plant Generator typical excitation is 600V at 8000A.
What is the difference between a seperately excited DC generator and DC shunt generator?
The difference between a separately excited DC generator and a Shunt DC generator is that for a separately excited Dc generator , the excitation field winding is supplied by an external source different from that supplying the armature while for shunt generator, the excitation field windind is connected in series with the armature and supplied by a single source.
What is the excitation of the generator?
The rotor must have a magnetic field in order to generator voltage in stator winding. The exciter circuit generates this DC filed in the rotor.
Where does the voltage that is necessary for field excitation on the rotor originates from?
The excitation current is provided by a small self-excited pilot generator, attached to the same shaft as the alternator's rotor.
What is the excitation system in a generator used for?
The excitation system is used to control the excitation of the rotating field in the armature. By increasing the armature current, it in turn increases the magnetic flux in the armature coil. This has the effect of increasing the voltage output of the generator. By lowering the armature current this in turn lowers the generator output voltage. The generator's voltage regulator automatically adjusts the output voltage continuously as the applied load on the generator changes.
Why loss of field-protection is important?
loss of field protection is important because when a synchronous generator looses field excitation its acts as an induction generator and draws reactive power from the system which heats and damages rotor so as soon as the loss of field excitation is sensed the generator breaker should be opened as the rotor and the stator would both heat up and could damage. Best Regards, Ayaz Ahmed
What is excitation and why is it needed for start up in an AC generator?
An alternator is just another name for a synchronous generator. Excitation is needed to create a magnetic field in the rotor. When to rotor is spun with excitation the magnetic field will cut through the stator field and produce an AC voltage in the stator field. In terms of an alternator with built in rectifier the stators AC voltage in the rectified to DC. The strength of excitation will determine the alternators output voltage. The AVR Automatic Voltage Regulator built into almost every alternator controls field current to maintain a constant output voltage.
Why is dc current used in the excitation of generator?
The field current is used for the excitation of generators.AnswerYou use DC current, because you want the resulting magnetic field to be constant. If you used AC, the resulting magnetic field would vary in both strength and direction.
