WEG AVR-A-OPT-16, Installation, Operation And Maintenance Manual

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| Automatic Voltage Regulator – AVR-A-OPT-16 14
9 OPERATION
9.1 VOLTAGE REGULATOR
It compares the actual output voltage from the generator with the theoretical adjusted value through the trimpot of voltage
adjustment P1, plus the external voltage adjustment (if any). The error is processed by the sensing loop whose value
determines the thyristor firing angle which may vary from 0 to 180°, thus controlling the output voltage of the generator.
9.2 POWER CIRCUIT CONNECTION
The generator voltage or the auxiliary winding voltage is connected to the terminals AC1, AC2 and AC3. This rectified voltage is
applied, in a controlled fashion, to the generator exciter field
.
9.3 FIELD FLASHING
Generation begins through the residual voltage of the generator. Once the voltage has reached about 10% of the nominal
voltage, the regulator controls the generator voltage causing it to rise through the initial ramp in approximately 3 seconds. When
the generator reaches its nominal value, the PID control loop will maintain the generator output voltage constant within the
adjusted value.
9.4 U/F OPERATION
This operation is determined by trimpot P3, jumper J1 and associated components. The J1 jumper determines the operating
frequency (50 or 60 Hz), following the logic below:
J1 A = 50 Hz
J1 B = 60 Hz
Trimpot P3 determines the set point of the U/F mode, that can be from the nominal frequency (Fn) down to 1/3 of Fn, the value
of which comes out of the factory adjusted to 10% below Fn. For operation at 60Hz it is adjusted to 54Hz and for operation at
50 Hz it is adjusted to 45Hz, the value of which can be changed based on each application requirements.
O
u
tp
u
t
v
o
lt
a
g
e
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V
a
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Frequency (Hz)
O
u
tp
u
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Frequency (Hz)
45
U
U/f
50
54
U
U/f
60