Answer / geeparthi

AVR's are normally used in the Diesel Generators.They are
used to control the output voltage depending upon load
connected , such that, the load will not cause any voltage
fluctuation and damage to the DG.
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.
AVR increase or decrease excitation voltage for linear
voltage.Frequency depends on primover speed.
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)).

AS the name itself indicates it is a device which maintains

Answer / kumar

As per my field experience AVR is automatic voltage
regulator which is provide for controlling or developing the
output voltage produced by ac generator .the input voltage
for AVR is drawn by field voltage is produced by RR
(rotating rectifier)

Answer / s.arunkumar

AVR means Automatic Voltage Regulator.
There are different types of excitation in generators, AVR
is used to regulate the voltage applied to the
generator.Because generator draw enoromous power from the
source in order to regulate this AVR is used.

Answer / rakesh

The function of the AVR is to automatically regulate the voltage of generators. As a load on a generator increases it's terminal voltage tends to droop.The AVR senses the drop in terminal voltage by measuring the generator voltage and boosts up the excitation to the field of the generator to maintain the terminal voltage at the set level.Similarly as the load on the generator falls, the terminal voltage is maintained by the AVR by reducing the excitation to the field.

Answer / raul

AVR- AUTOMATIC VOLTAGE REGULATOR
AVR is a device used to measure any difference in the
generator terminal voltage and highly stabilized reference
value, and if it detects any difference, it controls the
firing pulses of the thyristors connected in the
system.....to change the output voltage of the pilot
exciter which in turn changes the output of the main
exciter n ultimately the generator voltage........
IN SHORT, IT IS USED TO MAINTAIN THE GNEREATOR TERMINAL
VOLTAGE B/W THE TRANSIENT STABILITY LIMITS so that d
generator remains in synchronism

Answer / irfan

AvR is automatic voltage regulator.It controls the voltage being fed to rotor to get required voltage(rated). it uses feedback system to get the set voltage.

Answer / joginder singh

AVR is automatic voltage ragurator,there is diffrent type
of exitation on depend the load.and set the trminal volts,

Answer / david david

i need a help we use the genset but we connected the AVR but now the problems is the voiteg of the genset its going up and down im try to adjust the AVR but does,t help what can i do now?

Answer / k.prakashchandra

AVR maintains the set voltage at the same
value,irrespective of the speed

Answer / nageeb khalafalla mohammed

The AVR is (automatic voltage regulator)is an electronic circuit used to keep the generator voltage constant to the pre stetted value whatever the changes of the loads as the voltages tends to decrease with the increasing of the load so the AVR increases the exciting current and the opposite is done for increasing in the voltage . This is done by virtue of the thyristor in the AVR , the reference voltage circuit, the comparator circuit in the AVR .with the feedback circuit. the AVR senses the output voltage and increase or decrease the excitation accordingly to keep the voltage constant.

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