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A generator needs to have residual magnetism in its field coils to start the generation of electricity. A generator that has not been run in a long time will loose this magnetism. Because the field voltage is a DC supply, a battery across the field wiring will energize the coils instantaneously. Doing this several times will cause sparking when the contact to the battery is broken, hence the flash. This intermittent energizing and de-energizing will bring the residual magnetism back into the field coils. When the generator is started, the voltage output should rise to its normal level. If it does the magnetizing of the field coils to bring back the residual magnetism will have worked.
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What is meant by pole slipping?
A pole slip occurs when a motor or generator cannot maintain synchronicity. This occurs because the field excitation is too low.
How the DC generator are classified according to field excitation?
on the basis of field excitation, dc generators are classified into the following types:-1- separetly excited dc generators2-self excited dc generatorsthe behaviour of a dc generator on load depends upon the method of field excitation adopted
How can the field coils of a dc machine be connected with self excitation?
No
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.
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.
In synchronous motor theory is excitation current the same as field current?
yes. excitation current is same as field current to my knowledge
What is meant by pole slipping?
A pole slip occurs when a motor or generator cannot maintain synchronicity. This occurs because the field excitation is too low.
Generator excitation voltage?
the voltage which is given for creating magnetic field in a generator is known as excitation voltage.
What is transformer turns ratio excitation current?
This is the current level needed to energize a transformer to its rated voltageThe clue is in the name! 'Excitation' means to create a magnetic field. So the excitation current is the current drawn from the supply which sets up the magnetic field around the core.
What is meant by P0845 and flashing D?
What is meant by P0845 and Flashing "D" with regards to my 2003 Honda CRV
How the DC generator are classified according to field excitation?
on the basis of field excitation, dc generators are classified into the following types:-1- separetly excited dc generators2-self excited dc generatorsthe behaviour of a dc generator on load depends upon the method of field excitation adopted
How can the field coils of a dc machine be connected with self excitation?
No
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.
Difference between static excitation system?
It is called static excitation when you make use of solid state components like diode and thyristors to convert to pure dc and to use this dc for field excitation of synchronous generators. The field winding of synchronous generators can be excited by dc source only. It is called brushless excitation because use of carbon brushes are not made here.It is called dynamic excitation is when you make use of rotating brushes. Excitation is necessary to produce reactive power and also to regulate the voltage of synchronous generators.
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.
Which relay is used to detect the loss of excitation in generator?
A loss of field relay.
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.
