Stationary contacts
●
●
Inspect the arcing tips for excessive erosion.
●
●
Inspect the contact surface for pitting and scoring.
●
●
Replace excessively worn contacts.
Moveable contacts
●
●
Inspect the contacts for adequate contact surface area.
●
●
Run the tap-changer through all positions checking for
proper alignment with stationary contacts.
●
●
Replace excessively worn contacts.
Reversing switch contacts and mechanism
●
●
Inspect contacts for wear.
●
●
Inspect mechanisms for damage.
●
●
Replace excessively worn contacts.
Stationary contact board and moveable contact arm
●
●
Inspect for build-up of carbon on surfaces; wipe off any
build-up with a rag.
●
●
Inspect for signs of arcing or heat damage.
●
●
Inspect the phenolic contact boards found on legacy
tap-changers for scratches.
●
●
Upgrade the phenolic moveable contact arm to the
polymer version for the legacy QD8 tap-changer.
Holding switch
●
●
Inspect for proper operation of the switch.
●
●
Inspect contact surfaces of holding switches on spring-
drive and direct-drive tap-changers for pitting and proper
spacing as defined in the tap-changer manual.
Position indicator drive mechanism
●
●
Check the position-indicator gears on the tap-changer for
signs of damage or loose parts.
●
●
Check the drive cable for damage and signs of corrosion.
General
●
●
Inspect for any signs of arcing between contact, contact
boards, brackets, tap-changer mechanisms, and any other
components inside the tank.
●
●
Check hardware for tightness.
●
●
Check the reactor tie-rods for tightness.
●
●
Inspect the core and coil for insulation damage and heat
damage.
●
●
Remove any loose debris.
●
●
Evaluate an insulating fluid sample and compare the
results to the requirements found in
Related manuals
Review the following tap-changer manuals for additional
information on contact erosion and tap-changer
maintenance requirements:
●
●
MN225072EN,
QD3 Quik-Drive Voltage Regulator
Tap-Changer Manua
l
●
●
MN225012EN,
QD5 Quik-Drive Voltage Regulator
Tap-Changer Manual
●
●
MN225011EN,
QD8 Quik-Drive Voltage Regulator
Tap-Changer Installation and Maintenance Instructions
●
●
S225-10-2,
Spring-Drive and Direct-Drive Tap-Changer
Switches in VR-32 Operating, Maintenance,
Troubleshooting and Parts Replacement Instructions
Duty Cycle Monitor (DCM)
Another useful indicator of the need for inspection
and maintenance for voltage regulators equipped with
Quik-Drive tap changers is the DCM control feature.
Refer to Service Information MN225003EN,
CL-7 Voltage
Regulator Control Installation, Operation, and Maintenance
Instructions
, for more information on the DCM feature.
DCM will operate correctly only when a Quik-Drive
tap-changer is paired with a CL-6 or later control and the
control has been programmed with the correct design
specification number.
EVER-Tap voltage regulator
Consult the document MN225077EN (expected release
date Q4, 2020),
EVER-Tap Voltage Regulator Maintenance
Instructions
and the inspection recommendations below for
details on maintenance procedures.
500,000 operation inspection
Vacuum interrupter
●
●
Check the contact erosion indicator.
Bypass contacts
●
●
Inspect the contact surface for erosion.
Stationary contacts
●
●
Inspect the contact surface for pitting and scoring.
●
●
Replace excessively worn contacts.
●
●
Signs of arcing indicate a malfunctioning vacuum
interrupter or tap changer mechanism.
24
VR-32 and EVER-Tap™ Voltage Regulator
InstallatIon, operatIon, and MaIntenance InstructIons
MN225008EN June 2020
