Removal from service
Refer to the appropriate regulator manual as indicated on
the regulator nameplate for further information.
Determining neutral position
DANGER
Explosion Hazard. During bypass switching, the
regulator must be in the neutral position. Prior to
bypass switching: 1) The regulator must be placed in
the neutral position; 2) Tap-changer operation must be
disabled during the bypass switching. If the regulator
is in any other position, part of the series winding will
be shorted when the bypass switch is closed, resulting
in high circulating current. Failure to comply will result
in death or severe personal injury and equipment
damage. VR-T205.0
WARNING
Explosion Hazard. Bypass a regulator with the line
energized only if the position indicator, the neutral
light, and the control tap position indicate neutral and
the voltage measured between the source and load
bushings using an approved voltmeter is zero. If both
neutral indicators do not indicate neutral or there is a
voltage between the source and load bushings, the line
should be de-energized to avoid shorting part of the
series winding and resultant high circulating current.
Failure to comply can result in death or personal injury
and equipment damage. VR-T206.0
Return the regulator to neutral. Only a regulator in the
neutral position can be safely removed from service without
interrupting load continuity. It is recommended to use four
(4) methods to determine the neutral condition.
WARNING
Explosion Hazard. Always use the CONTROL FUNCTION
switch (labeled AUTO/REMOTE, OFF, LOCAL MANUAL,
and RAISE and LOWER) to operate the regulator, not
the power switch. Failure to comply can result in the
tap-changer stepping off of neutral immediately upon
being energized, causing personal injury and equipment
damage. VR-T207.0
WARNING
Explosion Hazard. To stop the regulator on the neutral
position, the CONTROL FUNCTION switch should be
returned to Off during the switching operation from
positions 1R or 1L to position neutral. Switching to
Off prior to reaching the neutral position prevents
overshoot. Failure to comply can result in death or
severe personal injury and equipment damage. VR-T208.0
Return the regulator to neutral
1. Use the Raise/Lower switch to bring the regulator to
the neutral position.
2. When in neutral, the Neutral light will be continuously
and brightly lit on the control front panel and the
position indicator will point to zero.
3. Verify the neutral position of the regulator using four
methods.
a. Verify that the neutral indicator light on the control is
indicating the neutral position. Neutral is indicated only
when the light is continuously and brightly illuminated.
b. Verify the tap position on the control indicates neutral
by using the Metering-PLUS key or FC 12. When in
neutral, the display will show "0" (zero).
c. Verify that the position indicator on the regulator is in
the neutral position. The indicator should point straight
up to either zero or N for Neutral.
d. Using an approved voltmeter, verify that there is
no voltage difference between the source and load
bushings.
WARNING
Explosion Hazard. After placing the regulator in the
neutral position for bypass switching, always disable
the motor to prevent a tap change during bypassing
which can result in the tap-changer stepping off of
neutral. Failure to comply can cause death or severe
personal injury and equipment damage. VR-T209.0
4. When the regulator has been placed in the neutral
position, but prior to bypassing, additional safety
actions must be taken to disable the tap-changer
motor and ensure that the tap-changer will not
inadvertently switch to an off-neutral position. This can
be accomplished by doing the following:
a. Place the CONTROL FUNCTION switch in the OFF
position.
b. Remove the motor fuse.
c. Place the control POWER switch in the OFF position.
d. Open V1, knife switch (and V6 if present) located on
the control back panel.
17
INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS MN225003EN April 2018
CL-7 Voltage Regulator Control
To Next Page
Loading...
