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CAUTION
Dielectric failure, equipment damage. Never use volatile
solutions, detergents, or water-soluble cleaners when
cleaning the interior of this equipment. These cleaners
will contaminate the insulating oil, reducing its dielectric
strength. Operation with contaminated insulating
oil can result in internal flashovers that will cause
equipment damage and possible personal injury.
6.
Clean the internal components:
A.
Remove all traces of carbon by wiping with a clean
lint free cloth. Flush the mechanism with clean, dry
transformer oil.
B.
If additional cleaning action is necessary, a
dielectric cleaner (Biogenic
Rochester Midland, Positron Dielectric Cleaner, or
similar) may be used to clean internal parts. Check
with your local regulating authorities to determine
which dielectric cleaners are permitted in your area.
After the cleaner has evaporated, the mechanism
must be thoroughly flushed or dipped in clean, dry
transformer oil to remove all cleaner residue. Even
dielectric cleaners with high dielectric strength
leave a residue that will affect oil insulating
properties if not removed.
7 .
Check the moving and stationary contacts.
A.
Dress slight pitting and discoloration with crocus cloth.
B.
Replace both the moving and stationary contacts
if they are severely eroded. Follow procedures in
"Shop Repair Procedures—Contacts" section.
N
ote:
The contacts should be replaced before the erosion
of the load current transfer surfaces impairs their
effectiveness.
8.
Manually close and trip the switch several times to
check that all components perform properly.
9.
Inspect tank lines. Note that two liners are employed.
The inner liner is fibrous and readily absorbs any
moisture present. Soft or spongy areas indicate water
has been absorbed. Replace the liner if such areas are
present. The outer liner need not be replaced unless it
is cracked or punctured.
10. Check the dielectric strength of the insulating oil.
A.
A sample taken near the bottom of the tank should
have a dielectric strength of not less than 22 kV.
B.
Low dielectric strength indicates the presence of
water or carbon deposits; replace the oil. (See "Oil
Condition" section.)
11. If oil must be replaced, drain the tank and discard the
tank wall liners.
12. Thoroughly clean out all sludge and carbon deposits
and rinse the tank with clean oil.
4
TYPE NR OIL SWITCH MAINTENANCE INSTRUCTIONS MN230001EN February 2016
T201.2
®
Electrosafe from
13. Install new tank wall liners and fill the tank with clean,
new insulating oil to within one inch of the top of the
tank flange. Oil capacity is approximately 1.5 gallons.
N
ote:
Use only new, or like-new reconditioned transformer
oil which conforms to the specifications in Reference
Data R280-90-1, Oil Specifications and Test.
14. Replace all external seals and gaskets.
15. Clean the head gasket seat and retank the switch.
A.
Replace the head bolts and torque to 15 ft-lbs.
Apply clamping force gradually and equally, in rota-
tion, to each bolt to achieve an evenly distributed
gasket sealing pressure.
16. Electrically operate the switch to check for proper oper-
ation. See "Operating Instructions—Electrical Operation"
section.
17 . Repeat the high voltage dielectric withstand test (Step
3) to make sure the dielectric clearances within the
tank have not been compromised.
Operating instructions
Electrical operation
The switch may be opened and closed electrically by
applying rated control voltage to the proper terminals of the
actuator terminal block. Figure 3 illustrates a connection
diagram for a standard three-wire control.
Closing: Approx. 1.5 sec
Opening: Approx. 4 sec
MOTOR
0 1 G 2 3 4
Figure 3. Typical connection diagram for three-wire
control.
AC-White, DC-Black
AC-Black, DC-Red
SEL
SW.
NO
NC
C
Black
Red
NOTE: G=Ground
2=Close
3=Open
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