Answer / magoola faruku

AVR MEANS AUTOMATIC VOLTAGE REGULATOR-BUT works hand in
hand with the thyristor bridge responsible for
transforming the ac to dc which is used in generating the
ac voltage and at the same time uses the feed back lines
from the output of main ac in line with what is set to
varify wether the ac as per set is ok or not. if not ok avr
requests the bridge to send a more dc or if less then
request to reduce on the dc and as such carrying out the
function of regulation

Answer / vivek g. acholkar

In D.G. set Excitation field is used for generate Voltage.
AVR is used to control Excitation field.If AVR fails the
Voltage will be not generated by D.G.set,but due to residual
magnetism it will running.(If there not available any auto
system to shut down Engine.example--POWERCOM )

Answer / sheikh

DG set AVR Failed means no excitation voltage to generator
then generator ouput e.m.f also will be 00 volts.in this
case generator should goes to shut down in safety of under
voltage.

Answer / malik

AVR is auto voltage regulator that simply means it regulate
the voltage.so if it fails we have to face over voltage
problem.if we want to cheack AVR is faulty or not we have
to bypass AVR by using battry.

Answer / big bull

It depends on whether the DG is connected to grid (infinite
bus) or stand alone. If it is stand alone, there is no
harm, there won't be any terminal voltage. But if the DG is
connected to grid then on loss of field generator draws
reactive power from grid to maintain terminal volatge. As
DG losses the field, it tends to over speed and behaves as
an induction generator.This may cause stability issues with
grid if the grid is small. also

Answer / rahul shukla

if AVR OF DG SET FAIL THEN EMF=0 AND DG WILL BE INDUCTIVE
LOAD IT WILL DRAW REACVE POWER FROM GRID .

Answer / lokesh

if AVR fails in DG sets emf production will be zero signal
will be sent to Governer engien will shut down

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