WARNING
Hazardous Voltage . When troubleshooting energized
equipment, protective gear must be worn to avoid
personal contact with energized parts . Failure to comply
can cause serious injury or death .
2. Conduct this test with the regulator located in the
maintenance shop or other suitable location.
WARNING
Hazardous Voltage . The regulator tank must be solidly
earth grounded . Failure to comply can cause severe
personal injury and equipment damage .
3. Ground the regulator tank.
4. Connect a cable sized for the regulator rated current
between the S (Source) and the L (Load) bushings.
5. Install a clamp-on ammeter on the cable between the S
and L bushings to verify the current during the test.
6. Open the
V1
(and
V2
,
V6
, and
V8
if present) and
C
switches on the control assembly back panel.
CAUTION
Equipment Damage . When connecting external power to
the voltage regulator control, make sure the polarity of
the power source is correct . Reverse polarity will result
in control damage .
VR-T235 .0
CAUTION
Equipment Damage . Only an AC power supply is to be
used to energize the control externally . Do not use a
DC-to-AC voltage inverter . Failure to comply can cause
excessive harmonics to be generated and result in
damage to the front panel .
VR-T204 .1
7. Apply 120 Vac to the control
EXTERNAL SOURCE
terminals. For instruction on connecting the control
to an external source, see Service Information
MN225003EN,
CL-7 Voltage Regulator Control
Installation, Operation, and Maintenance Instructions
.
8. Using the manual
RAISE/LOWER
switch, place the
regulator on the 3 Raise position.
9. Check control settings and correct if necessary. Ensure
that FC56 is set for bidirectional. This will allow the
control to function in both the forward and reverse
power flow arrangements.
10. Connect a variable source between the L and SL
(Source-Load) bushings and increase the applied
voltage until 50% of the current rating is reached: this
should be around 55 V.
11. Depending on the polarity of the voltage applied to the
L and SL bushings, the control will operate in either
the forward or reverse power flow direction. If the
control
REVERSE POWER
LED does not illuminate, the
control is in the forward mode. Reversing the voltage
source leads on the L and SL bushings should cause
the control panel
REVERSE POWER
LED to illuminate,
indicating the control is in the reverse power flow
mode.
Voltage regulator ratio test
Purpose
The purpose of this test is to:
●
●
Confirm correct series winding tap-changer connections.
●
●
Identify an open or short-circuit in the series or shunt
windings.
Required equipment
●
●
Voltmeter
●
●
2 - 120 V variable power supplies
Procedure
WARNING
Hazardous Voltage . This procedure must only be
performed on a regulator that has been removed from
service . Failure to comply can cause serious injury or
death .
1. Remove the unit from service as described in
2. Connect a voltmeter between the L (Load) and SL
(Source-Load) bushings.
3. Use a variac to apply 120 Vac between the S (Source)
and SL bushings.
CAUTION
Electrical Shock Hazard . Connecting an energized
variac to the bushings will expose the tester to 120 Vac .
Contact with the bushings will result in an electrical
shock .
WARNING
Electrical Shock Hazard . The V1, V2, V6, and V8
(whichever are present) knife-blade switches must be
open when connecting external power to the control .
With some controls, if 120 Vac is incorrectly applied to
the voltmeter terminals and the switches remain closed,
rated voltage could be created on the bushings . Contact
with the bushings in such a case could result in death
or serious injury .
CAUTION
Incorrect connection of an external power source to
the control or supply of an over-voltage will result in
damage to the control panel .
30
VR-32 and EVER-Tap™ Voltage Regulator
InstallatIon, operatIon, and MaIntenance InstructIons
MN225008EN June 2020
