Answer / boopathiraja

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 / srij21

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.

Answer / pankaj

AVR generally used in generators The function of AVR is :
due to residual flux, initialy residual voltage build up in
the alternator, this voltage given to avr which compare the
output voltage of the alternator with the setr efrance
voltage and controls the output voltage.

Answer / ash

The AC synchronous generator usually uses the AVR to
regulate the magnetic field/s strength of the exciter
stator. The AVR samples the main generator/s Real-time
output voltage ,which compared with the value preset, then
there will be a result ,which can regulate the PWM(pulse
width modulation).
If the output voltage value is higher, then the narrow
pulse width will be output, and vice versa, then using
these pulse to control the high-power transistor to control
the current time, which pass the exciter stator winding.
Thus the magnetic field strength will be change in the
opposite of the main generator output voltage. Namely, the
higher voltage output, the lower exciter stator magnetic
field, and vice versa, so as to achieve the purpose of the
negative feedback regulation.

Answer / bhanu pratap

to understand the function of AVR first v have to understand
concept of reactive power....

all of u know reactive power..



a generator has active power and reactive power... infact
with out reactive power ther will be no generation..


reactive power is the one which is the power consumed for
the establishment of magnetic flux in the machine without
which no generation takes place....

coming to the AVR..
consider a generator supplying to the grid.. as the grid is
not purely resistive.. it generally is inductive since loads
connected to grid(consider industries)are inductive..
generator tries to draw reactive power from the grid for the
development of its magnetic flux...(under constant frequncy)




when frequncy changes ..it disturbs the magnetic flux ...so
the geneartor tries to draw more n more reactive power from
the grid.. if this happens .. rotor of the generator will
get heated due to this reactive power..


so here comes d AVR... avr produces the xtra amount of
voltage required for the machine to maintain its magnetic
fld so that (V/F) will be constant...


thats wat i feel.. inform if any corrections




when

Answer / atreya

AVR stands for Automatic Voltage Regulator. In case of
synchronous generators, it is used to control the generator
terminal voltage and maintain it at a certain set-point(
say 11 kv) by controlling the excitation voltage of the
exciter of the sync. generator.

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