formals to calculate exciation voltage of alternator
excitation voltage is sinusoidal because it is taken from the terminal of alternator but excitation current is non-sinusoidal because it always dc.
In an alternator, the load current is supplied by the stator and the excitation is applied to the rotor. When the power factor is low (lagging), more excitation is required to maintain rated output voltage at rated current. More excitation is also required to maintain rated output voltage with increased output current. Increased excitation current means increased rotor losses that must be dissipated as heat. (akash)
E=Vt + Ia jXS Where E excitation voltage Vt Terminal voltage Stator Current Ia Xs synchronous Reactance
A transformer's excitation current can be resolved into two components. The first is in phase with the primary voltage, and is responsible for the losses. The second lags the supply voltage by 90 degrees, and is responsible for magnetising the core.
the voltage which is given for creating magnetic field in a generator is known as excitation voltage.
excitation voltage is sinusoidal because it is taken from the terminal of alternator but excitation current is non-sinusoidal because it always dc.
Regulation of an alternator is varying or adjusting the d.c. current flow (excitation current) in the revolving field coil to control the output voltage. When an alternator is subject to varying load conditions, and therefore changing load resistance at the output, the output voltage will vary in response. When output voltage is reduced in response to increased load (reduced output resistance), the "voltage regulator" will respond by increasing the excitation current to increase the voltage output. If load is reduced, the generator will momentarily become over-excited and the ouput voltage will increase. The voltage regulator responds by decreasing excitation current, returning the generator output voltage to its nominal level.
The excitation current is provided by a small self-excited pilot generator, attached to the same shaft as the alternator's rotor.
In an alternator, the load current is supplied by the stator and the excitation is applied to the rotor. When the power factor is low (lagging), more excitation is required to maintain rated output voltage at rated current. More excitation is also required to maintain rated output voltage with increased output current. Increased excitation current means increased rotor losses that must be dissipated as heat. (akash)
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.
E=Vt + Ia jXS Where E excitation voltage Vt Terminal voltage Stator Current Ia Xs synchronous Reactance
due to residual magnetism
A transformer's excitation current can be resolved into two components. The first is in phase with the primary voltage, and is responsible for the losses. The second lags the supply voltage by 90 degrees, and is responsible for magnetising the core.
A typical alternator uses permanent magnets mouted on the rotor. Their movement excites the stator of wound coils in the housing. The resulting AC current is rectified and controlled by diodes and a voltage regulator, also typically mounted inside the housing.
By Decreasing the excitation voltage the terminal voltage will decrease and similarly by increasing the excitation voltages the terminal voltage will also increases.
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.