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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.


What is meant by excitation of synchronous machines?

Excitation of synchronous machines refers to the process of supplying direct current (DC) to the rotor winding to create a magnetic field, which is essential for the operation of the machine. This magnetic field interacts with the rotating magnetic field produced by the stator, enabling the machine to generate or synchronize with the grid frequency. Proper excitation is crucial for maintaining voltage levels and ensuring stable operation under varying load conditions. Inadequate or excessive excitation can lead to issues such as voltage instability or oscillations.


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


What is over excitation of field windings?

Over-excitation of field windings refers to a condition in synchronous machines, such as generators, where the field current exceeds the rated value, leading to an excessive magnetic field. This can result in increased voltage output and potential overheating of the machine. Prolonged over-excitation can damage the windings and other components due to overheating and insulation breakdown. It is critical to monitor and control the excitation levels to maintain safe and efficient operation.


How can the field coils of a dc machine be connected with self excitation?

No

Related Questions

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.


What is meant by excitation of synchronous machines?

Excitation of synchronous machines refers to the process of supplying direct current (DC) to the rotor winding to create a magnetic field, which is essential for the operation of the machine. This magnetic field interacts with the rotating magnetic field produced by the stator, enabling the machine to generate or synchronize with the grid frequency. Proper excitation is crucial for maintaining voltage levels and ensuring stable operation under varying load conditions. Inadequate or excessive excitation can lead to issues such as voltage instability or oscillations.


What is meant by P0845 and flashing D?

What is meant by P0845 and Flashing "D" with regards to my 2003 Honda CRV


Generator excitation voltage?

the voltage which is given for creating magnetic field in a generator is known as excitation voltage.


What is meant by static excitation?

Static excitation refers to a method of supplying direct current (DC) to the rotor windings of a synchronous machine, such as a generator, to establish a magnetic field. This excitation is "static" because it typically involves the use of a stationary power source, like a rectifier, to convert AC voltage from the generator into DC. The static excitation system allows for precise control of the machine's output voltage and reactive power, enhancing stability and performance. It contrasts with dynamic excitation systems, which use rotating equipment to provide excitation.


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.


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


What is over excitation of field windings?

Over-excitation of field windings refers to a condition in synchronous machines, such as generators, where the field current exceeds the rated value, leading to an excessive magnetic field. This can result in increased voltage output and potential overheating of the machine. Prolonged over-excitation can damage the windings and other components due to overheating and insulation breakdown. It is critical to monitor and control the excitation levels to maintain safe and efficient operation.


How can the field coils of a dc machine be connected with self excitation?

No


In synchronous motor theory is excitation current the same as field current?

Yes, in synchronous motor theory, excitation current is the same as field current. This current is used to produce the magnetic field in the rotor that interacts with the stator current to generate torque and make the motor operate synchronously.


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.