Installation Guide

2022.02 / l
7
Electric Power Generation
Installation and maintenance
R120
AVR
5243 en -
The AVR builds up the generator voltage
from its residual voltage to rated voltage.
When the generator is loaded, the sensed
voltage decreases and generates an error
signal, which is required in order for the
closed loop system to work.
Depending upon the value of the amplied
voltage, the ramp intersects the amplied
voltage at a point which is early or late in the
half-cycle.
At this intersection point, a starting pulse is
produced to trigger the power device.
Only qualied personnel should replace/
work on the AVR.
Do not increase the voltage beyond the
rated voltage.
5 - AVR SETTINGS
5.1 - V-TRIM (V)
This function is provided for setting the
voltage up to ± 10% of rated voltage by
means of a potentiometer. Turn the
potentiometer clockwise to increase the
voltage and vice versa, once the rated
speed has been reached.
The default setting is 415 V ± 2% for
3-phase, 240 V ± 2% for 1-phase.
5.2 - UNDER FREQUENCY KNEE
POINT SETTING (UF)
This function is provided to protect the AC
generator from sustained low speed
operation through a potentiometer. The AVR
will reduce the voltage in proportion with the
speed below the dened value.
The procedure for setting the UF
potentiometer is as follows:
First run the generator at full speed (50 Hz)
and turn UF by a few turns clockwise,
making sure that the voltage does not
increase. Now turn the UF potentiometer
slowly anticlockwise. At a particular point
the red LED glows and the voltage will start
to decrease. Stop turning the potentiometer
at this point and turn the potentiometer
clockwise by two turns after rated voltage is
restored.
The factory default setting is 46 Hz.
5.3 - STAB (S)
This function is provided to stop voltage
hunting by means of a potentiometer. Turn
clockwise to increase stability (to stop
oscillation). Turning too far clockwise will
result in a sluggish response and possibly
also oscillations.
The factory default setting is slightly
higher than critical damping (around
halfway).
6 - AVR CONTROLS
No. Control Function Direction
1 VOLTS Sets the generator output voltage Turn clockwise to increase output voltage
2 STAB Stops voltage hunting Turn clockwise to increase stability
3 UFRO
Sets the Under frequency
knee point
Turn clockwise to to reduce the knee
point