Operation; Voltage Regulator; Power Circuit Connection; Field Flashing - WEG AVR-A-OPT-07 Manual De Instalación, Operación Y Mantenimiento

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14.

OPERATION

14.1.

VOLTAGE REGULATOR

It compares the actual output voltage from the alternator with the theoretical adjusted value through the trimpot
of voltage adjustment Vad, 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 alternator.
14.2.

POWER CIRCUIT CONNECTION

The alternator voltage or the auxiliary winding voltage is connected to the terminals 2 and 3. This rectified
voltage is applied, in a controlled fashion, to the alternator exciter field.
14.3.

FIELD FLASHING

Generation begins through the residual voltage of the alternator. Once the voltage has reached about 10% of
the nominal voltage, the regulator controls the alternator voltage causing it to rise through the initial ramp in
approximately 3 seconds. When the alternator reaches its nominal value, the PID control loop will maintain the
alternator output voltage constant within the adjusted value.
14.4.

U/F OPERATION

This operation is determined by trimpot U/F, jumper J1 and associated components. The J1 jumper determines
the operating frequency (50 or 60 Hz), following the logic below:
•
J1 pins 1 and 2: 60 Hz
•
J1 pins 2 and 3: 50 Hz
Trimpot U/F 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 (see Figure 14.4.), the value of which can
be changed based on each application requirements.
U/f
16 l Automatic Voltage Regulator – AVR-A-OPT-07 / AVR-A-OPT-07E / AVR-A-OPT-07/T
U
Frequency (Hz)
45 50
Figure 14.4.1: U/F operation
U
U/f
Frequency (Hz)
54 60