Answer / vasanth

to regulate the excitation voltage in generator AVR is used.
it compares the voltage, current and frequency of the
generator.

Answer / sivakumar

AVR is an abbreviation for Automatic Voltage Regulator.It
is important part in Synchronous Generators, it controls
the output voltage of the generator by controlling its
excitation current. Thus it can control the output Reactive
Power of the Generator

Answer / vijay

the fullform of avr is Autometic voltage regulator,
basically avr is used in transformer and genrators.

in transformer it works with PT and a tap changer motor
which autometically change the tap to control the voltage.

in genrators avr sense the voltage with the help of PTs and
control the exciting current in exciter to canrol the
voltage.

Answer / satish babu

AS the name itself indicates it is a device which maintains
the required output terminal voltage & hence called as
Automatic voltage regulator,
a) In case of alternators the Terminal Voltage(TV) is ref.
& whenever the TV tend to fall due to load the drop is
immediately sensed & excitation is increased thereby the
required voltage is maintained in the output terminals.

b) In case of transformer the PT output is the ref. As the
voltage drops due to load an immediate signal is given to
Tap changer motor (raise/lower)which varies the tap
position in the transformer thereby achieving the required
Terminal voltage.

In Both these equipments AVRs are used,which is an
electronic device which has an inbuilt comparator &
regulator.

Answer / v.k.rajput

AVR increase or decrease excitation voltage for linear
voltage.Frequency depends on primover speed.

Answer / senthil kumar

It is important part in Synchronous Generators, it controls
the output voltage of the generator by controlling its
excitation current and thus , it could control the output
Reactive power of the generator.

Answer / er. jackson s.

AVR stands for Automatic Voltage Regulator.

It is a device used to maintain a constant voltage at the
alternators terminals. It functions by maintaining the
excitation required to maintain the terminal voltage of the
alternator with change in the load.

Increase in excitation voltage increases reactive voltampere
(var) which decreases powerfactor (cos(phi)).

generally, voltage(V) of the alternator is kept constant so
thE rest of the components in VIcos(phi), ie. I and cos(phi)
have to vary according to the load.

Increase in I causes decrease in Pf and Decrease in I causes
increase in Pf.

so it is clear that Excitation V is proportional to var and
load current (I) and inversely proportional to power
factor(cos(phi)).

hope this helps.

Answer / elec.eng.babikir sharief

The AVR is control output voltage come from genrator by
measueing the voltage output, used to make stablity and
protaction genset

Answer / jai prakash narain singh

AUTOMATIC VOLTAGE REGULATOR(AVR) IS PART OF THE EXCITATION
SYSTEM OF A ALTERNATOR,WHERE IT REGULATE THE GENERATOR
OUTPUT VOLTAGE BY INCREASING/DECREASING THE EXCITATION
CURRENT OF EXCITATION FIELD.
THE PURPOSE OF AVR IS TO BUILD UP RESIDUAL VOLTAGE TO
NOMINAL VOLTAGE LEVEL AND MAINTAIN THE NOMINAL VOLTAGE
IRESPECTIVE OF LOAD,in addition to regulating generator
voltage,the avr circuitry includes under speed and sensing
loss protection features.excitation power is directly
derived from the generator terminals.

Answer / vinoth.m

AVR - Automatic Voltage Rwgulator which is normally used in
ups to supply a regulated output to the load.

Differance between power circuit and control circuit

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