the voltage which is given for creating magnetic field in a generator is known as excitation voltage.
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.
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.
excitation voltage is sinusoidal because it is taken from the terminal of alternator but excitation current is non-sinusoidal because it always dc.
E=Vt + Ia jXS Where E excitation voltage Vt Terminal voltage Stator Current Ia Xs synchronous Reactance
by increasing the terminal voltage
By Decreasing the excitation voltage the terminal voltage will decrease and similarly by increasing the excitation voltages the terminal voltage will also increases.
The generator terminal voltage will increase.
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.
The rated voltage of a generator decreases due to many causes such as armature reaction, overloading of the generator and AVR failure/ weak excitation voltage.
First you have to understand how a generator works. Basically the excitation voltage is what varies according to generator output. Usually on a power source that has a inconsistant rpm, the excitation voltage will vary similar to a govenor in order to hold the generator output constant.
Voltage regulation of a separately excited generator is generally better than that of a shunt excited generator because it allows for independent control of the excitation level. In a separately excited generator, the excitation current can be adjusted without being influenced by the load current, leading to more stable output voltage under varying load conditions. In contrast, a shunt excited generator's field winding is connected in parallel with the load, making voltage regulation more susceptible to changes in load, which can lead to voltage fluctuations. Thus, the separate excitation enhances performance in terms of maintaining a constant voltage.
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.
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.
The excitation current is provided by a small self-excited pilot generator, attached to the same shaft as the alternator's rotor.
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.
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.
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.