What is excitation current in alternator?
An excitation voltage or current is the amount of electric energy ( D.C ) feed into the field winding of an alternator rotor to produce magnetic flux / field. The output voltage of an alternator depends upon the magnetic field and so the excitation voltage.
Why excitation is required for alternator?
Why does the excitation system matter? Without the excitation system the AC alternator would have no way of building its voltage as it starts to rotate, nor would not be able to regulate its voltage to the pre-set nominal level while running at its rated speed.
Why do synchronous generators need excitation?
Excitation in an electrical machine means production of magnetic flux by passing current in the field winding. In order to excite the field winding on the rotor of the synchronous machine the direct current is required.
How do I calculate alternator excitation voltage?
Re: Alternator Excitation Voltage KVA at 5 MW = 1.732 * 11* 328 = 6249 KVA. excitation required at 5 MW = 6249*150/9373 = 100 V.
What is an excitation current?
Excitation current is the current flowing into the high voltage winding with the low voltage side open. This current should be proportional to the No-load acceptance test but with the difference resultant from the use of test voltages different from nominal values.
Which generator is used for excitation in alternator?
The pilot exciter is the shaft driven permanent magnet generator having rotating permanent magnets attached to the shaft and a three phase stationary armature, which feeds the main exciter field through silicon rectifiers, in the field of the main alternator.
What are the different methods of excitation of generator?
There are three methods of excitation, and thus three main types of DC generators:
- Permanent Magnet DC Generators – Field coils excited by permanent magnets.
- Separately Excited DC Generators – Field coils excited by some external source.
- Self Excited DC Generators – Field coils excited by the generator itself.
What is excitation current?
What is excitation voltage in synchronous generator?
current that circulates in the rotor or field winding. A. synchronous generator excitation voltage is the voltage. measured at the generator terminals when the load current is. equal to zero.
How do you measure excitation current?
the exciting current measurement is performed by applying an aC (60hz) Voltage (typically at 10kV) across a primary winding of the transformer while simultaneously measuring the current flowing through the same primary winding (while the secondary and ter- tiary winding(s) of the transformer are open-circuited).
What is the basic principle of generator excitation?
Principle of Static Excitation System. In Static Excitation System, power for providing field excitation is derived from the Generator output terminals. A transformer know as Excitation Transformer, is connected to the output terminals of Generator to step down the voltage to required voltage level usually 415 V AC.
What are the types of generator excitation?
TYPES OF EXCITATION SYSTEM . Today, a large number of different types of exciter systems are used. Three main types can be distinguished: DC excitation system, where the exciter is a DC generator, often on the same axis as the rotor of the synchronous machine. AC excitation system, where the exciter is an AC machine with rectifier.
How should excitation work in a generator?
Amplifier principle. Except for permanent magnet generators,a generator produces output voltage proportional to the magnetic field,which is proportional to the excitation current; if there is no excitation current
How do you excite a generator?
– Remove the fan belt from the vehicle or machine the generator starts. – Attach the jumper wire to the armature terminal on the generator. – Touch the other end of the jumper wire to the positive terminal on the battery.