Setting the Manual (Hard) Limit
Switches
Refer to the
CONSTRUCTION AND OPERATION:
Position Indicator and ADD-AMP Capability
section of
this manual for a complete discussion of these features.
Before setting the manual limit switches, be sure the new
settings will not conflict with the present tap-changer posi-
tion; see Figure 12. Do not set the switches below the
indicated tap-changer position. For example, if the main
hand is at step 12 and the change to be made is from plus
or minus 10% (step 16) to plus or minus 5% (step 8), run
the tap-changer back to step 7 or less, manually. Then set
the limit switches for plus or minus 5% regulation.
Limit switches should be set in anticipation of the maxi-
mum deviation of primary voltage. For example, on a
circuit where 7200 V is to be maintained, plus or minus
10% will permit voltages between 6480 V and 7920 V to
be regulated effectively. For voltages outside this range,
the regulator will not be able to return the voltage to the
preselected level (7200 V). Five percent regulation would
accommodate circuit voltages between 6840 and 7560 V,
maintaining 7200 V for all voltages in this range.
To set the limit switches, follow this procedure:
.
Unlatch the captive bezel and swing the cover open.
2 .
Lift the limit-switch adjustment lever free of the detent
and slide it to the new setting allowing the lever to snap
into the detent stop.
NOTE:
If the ADD-AMP limits have been programmed into the
control (soft ADD-AMP) and the limit switches have not
been set, it is possible to manually step the tap-changer
beyond the soft ADD-AMP limit. If the unit is switched
back to automatic mode, the control will step the regula-
tor back to within the soft ADD-AMP limits as set in the
control.
VR-32 Voltage Regulator Installation, Operation, and Maintenance Instructions
2
Figure 12 .
Position indicator .
