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for torque improvement in armature and create n-pole or s-pole in armature a dc source is used in alternator armature.
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∙ 12y ago
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Why The Excitation current is non-sinusoidal when applied voltage is sinusoidal?
excitation voltage is sinusoidal because it is taken from the terminal of alternator but excitation current is non-sinusoidal because it always dc.
For a 3 phase alternator why there is an AC voltage generated in the absence DC excitation?
due to residual magnetism
What is brushless excitation system?
3 phase synchronous generator or motor require DC current in the rotor. Conventional way of supplying DC requires use of commutators, which requires timely maintenance. To overcome this Brush less Excitation systems is used. Brushless Escitation system consists of one pilot excitor - DC generator with rotating PM as the field and the armature as the stator. The armature of the pilot excitor is connected to the stator of main excitor which is a 3-phase synchronous generator (please do not get confused, this is not our alternator but the exciter for the alternator). The rotor of the main exciter is connected to a diode bridge to get DC. This is connected to the rotor of our alternator.
Who is the main target for AC DC?
The main target of AC AND DC IS TO GIVE SUUPLY TO CONUMERS WERE AS AC CURRENT IS CHEAPER COMPARING WITH DC
What is excitation of a DC motor?
DC 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.
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 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.
Is reluctance motor is a synchronous motor with dc excitation?
yes
How can the field coils of a dc machine be connected with self excitation?
No
How do you cut off the excitation of a dc motor?
short leads
What happen to the apparent power if the DC excitation is reduced?
'Apparent power' is a term used in a.c. circuits, NOT d.c. circuits.
