Answer / sachin

Failure of AVR means failure of Excitation, hence DG will
continue running but no EMF (Voltage) will be generated.

Answer / saleem.d

I think
AVR = Automatic Voltage Regulator
Regulator Means it will controls the unit.So If AVR fails
in DG set we con't get constent continiues o/p voltage. Any
comments ?

Answer / rajesh patel

Failure of AVR means AVR will not deliver the excitation
voltaage to the exciter winding.Hance Excitor winding will
not be able to generate any excitor voltage.So there will
be no any field votage to rotor field winding and due to
this even if DG continious running but there will be no out
put voltage

Answer / dharamvir punia

If AVR fails in DG sets,it means no d.C. supply recevied
by DG sets Coils, no magnetic field made & coil does`t
excited, result no output given by sets.

Answer / sandeep jhajhra

IF AVR fails in dg set then the exitation voltage is zero
and we do not get any output voltage.

Answer / sunil datta

then no emf will induce, because rotor is not energized.and
rotor will not become magnet at all.

Answer / trilok kumar

AVR-AUTOMATIC VOLTAGE REGULATOR. AS THE NAME IMPLIES IT IS
USED FOR THE REGULATION OF VOLTAGE & VOLTAGE BUILD UP
PURPOSES.IT CONSISTS OF (VOLTAGE SENSING UNIT,VOLTAGE BUILD
UP CKT,PULSE WIDTH MODULATION CKT,etc...,).OBVIOUSLY IF AVR
FAILS THERE WILL BE NO VOLTAGE.SO DG RUNS WITHOUT VOLTAGE
AND THERE WILL BE NO LOAD.

Answer / ajay

1. If the avr is not giving any output voltage ie DC to the
excitor then no voltage build up will be there.
2. If the avr is not changing the dc voltage as per load
demand then voltage variation will be observed.Which means
the automatic rerulation function of avr wrt load is not
working.Hence avr needs replacement.

Answer / chauhanalpesh

it depends upon which type of avr is that .. if its an
static one than it will get tripped and no dc output and dg
set will not generate any voltage. but if avr having no
interlock with excitor than if avr fails than it will only
affect the regulation of voltage as excitation voltage is
already generating and being given to alternator so output
will be there but non-regulated

Answer / jai prakash narain singh

if avr fails,field excitation will be zero and hence no
rated voltage,but residual voltage will be always there.
dg breaker will trip due to under voltage protection .

Why dc Supply used in Control circuit.

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