precautions are necessary to ovoid the possi
bility of energizing the transformer in reverse
through the potential transformer and to ovoid
short circuiting the external supply through the
ground connection.
To make the settings proceed as follows:
1. Set resistance and reactance com
pensator dials both on zero. Set 90R lower
and 90L higher than their final settings.
NOTE: Always adjust
90R
and
90L
contacts by
moving the handles attached to the stationary
contact assemblies. See Figure
7.
2. If the relay is not in service apply
approximately 120 volts for one hour before
making settings. This allows the relay to
reach normal operating temperatures. If
the relay is in service proceed immediately
with step nl\mber 3.
3. Apply to the test terminals the exact
voltage at which the tap changer is
to
operate
in the raise direction. For example, con
sider 119 volts. Since the CVR-1 is very
highly damped the voltage should be held at
this level for about one minute. The disk
contact will now be at its 119 volt position.
Set the control selector switch on "AUTO"
and move the left hand scale pointer until
the 90R contact just touches the moving
contact, picking up the auxiliary control re
lay and operating the tap changer in the
raise direction.
Place control selector
switch in "MAN" position.
4. Apply to the test terminals the exact
voltage at which the tap changer is to oper
ate in the lower direction. For example,
consider 121 volts. Hold the test voltage at
121 volts for about one minute to allow the
disk contact to reach its 121 volt position.
With the control selector switch on "AUTO"
move the right hand scale pointer until the
90L contact just touches the moving contact,
operating the tap changer in the lower
direction.
5. The CVR-1 relay is now set to hold
regulated output between the limits of 119
and 121 volts or at a nominal 120 volt level
Page 7
(balance voltage) with a 2 volt (±1 volt)
bandwidth.
6. The CVR-1 relay will operate satis
factorily with any combination of contact
settings between 105 and 135 volts and the
tap changer will provide excellent quality
regulation with set bandwidths of 2 volts or
greater, that is, balance voltage ±1 volt.
7.
For any other settings, determine
the limit settings for 90R and 90L of the
voltage regulating relay and proceed as out
lined in 2 through 6.
8. Refer to Time Voltage Curve Figure
10 and set damping magnet for desired time
delay characteristic.
9. Set resistance and reactance com
pensation dials as required (see page 14).
10. When tests are completed return the
test Rheostat Knob to the "OFF" position.
Setting the CVR-1 Relay with load
Tap Changer Energized
A test voltage adjustment rheostat (RH) is
located on a control panel inside the CVR-1
case for your convenience. It makes pos
sible setting the relay by using the control
voltage with the tap changer energized.
Turning the Test Rheostat knob clockwise
will adjust the voltage applied to the relay
by means of the rheostat which is in series
with the control voltage and is located ahead
of the test terminals. (See Diagram Figure
5). Proceed as follows:
1. Set resistance and reactance com
pensator dials both on zero. Set 90R lower
and 90L higher than their final desired set
tings.
NOTE: Always adjust
90R
and
90L
contacts by
moving the handles attached to the stationary
contact ossembl ies. See Figure
7.
2. If the relay has not been in service
for at least an hour, allow up to an hour be
fore making settings in order for the relay
to reach normal operating temperature.
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