5. Time Delay : Corrective action takes place only after the Time
Delay as set by this control has elapsed and the
PT Voltage continues to remain outside the set
Lower or Raise limits (but does not fall below the
UV / OV limit).
6. Test/Normal Switch for AVR : It selects the Test or Normal mode of operation. In
the Test mode, PT Voltage is simulated internally
& can be varied through the Test Control on the
front panel. An LED indication is provided to
indicate that the instrument is in Test mode. In the
Test mode, the control relays are “cut off” so that
undesired operation of OLTC is prevented during
testing. The voltage is monitored on the display in
PT I/P position. In the Normal mode external PT
voltage gets connected to the instrument.
This switch must be kept in ‘’Normal” mode when
the instrument is in use.
7. Test Voltage Control : Simulates PT I/P in Test mode and can be varied
from 0V to 150V AC.
8. Test / Normal Switch for TPI : In the Test mode, display indicates "88" for
checking the display. In Normal mode it displays
the actual tap no. of OLTC. This switch must be
kept in "Normal" mode.
9. Selector Switch : Selects the voltage setting to be monitored on the
display. It also enables the PT voltage to be read
on the display.
NOTE : Before connecting Aux. Supply & PT Supply to the AVR Relay, Check-up
following points.
A) Mechanical Damage : Remove the front acrylic cover by removing the
thumbscrews & check for any mechanical damage to the unit.
B) Aux fuse & PT fuse (on Rear Panel) : Note that Aux. fuse is 300mA (20mm)
& PT fuse is 100mA (20mm). Do not interchange these fuses. Check them &
replace with good ones if required.
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