20
The cantilever strength should not be exceeded under any
combination of forces.
Lightning Arrester Installation Procedure
1 .
If an insulating base is used, bolt it to the mounting
bracket. If the insulating base is installed, but not used for
recording or measuring equipment, ground bottom unit
above insulating base.
2.
The bottom arrester unit (see master nameplate) is
bolted to the insulating base, or the foundation if no base
is used. Include the ground terminal assembly under one
of the mounting bolts-above the mounting foot.
3.
After the bottom unit and associated parts are firmly
anchored, install remaining units as indicated on the mas
ter nameplate.
4.
Terminals
Terminal connectors, suitable for use with copper . or
aluminum, are supplied with each pole. Bolt to the ground
terminal bracket, and to the line terminal of metal top ar
resters to form the line terminal assembly. These terminals
accept cable
.2 50
to .750 inch diameter. Line terminals
on porcelain top units accept
.255
to
.68 1
inch diameter
cable.
5 .
For metal top arresters, bolt the line terminal assembly
to the top unit.
The
IVL
or
CPL
arrester requires no regular mainte
nance other than occasional inspection. In locations where
the porcelain becomes contaminated by dirt, soot, salt,
etc . , it is recommended that the arresters be cleaned pe
riodically.
5 . 15
Current Transformers
Current Transformers are optional accessories. They are
mounted inside the transformer tank around the trans
former line leads. When the bushing is on the cover, the
current transformer is mounted to the bottom of the
cover around the bushing. When the bushing is on the
tank wall, the current transformer may be mounted on
top of the core and coil assembly. Current transforme r
secondary leads are always wired to a junction box on the
tank cover. Refer to the transformer wiring diagram to
identify the wire codes. The current transformer second
ary leads are always shorted and grounded to the tank
when the transformer is shipped.
CURRENT TRANSFORMER SECONDARY LEADS
MUST BE CONNECTED TO A LOAD OR SHORT CIR
CUITED WHEN THE TRANSFORMER IS ENERGIZED.
IF THE S E C ON DARY LEADS ARE OPEN, EX
TREMELY HIGH PEAKS OR PULSES OF VOLTAGE
ARE PRESENT AT THE SECONDARY TERMINALS.
THESE HIGH PEAKS OF VOLT AGE MAY NOT REG
ISTER ON CONVENTIONAL VOLTMETERS, BUT
THEY CAN BREAK DOWN INSULATION AND ARE
DANGEROUS TO PERSONNEL.
5 . 1 6
In
e
rt
ai
re
®
Inertaire® is the system for maintaining a cushion of in
ert dry gas above the liquid of transformers. When In
ertaire® is supplied, obtain Instruction Leaflet
48-063-36.
A copy of that Instruction Leaflet is usually shipped in
side the Inertaire® control cabinet.
5 . 1 7
Radiators
When radiators are shipped detached, all openings will be
closed with blind flanges and plugs. These should be ex
amined for signs of damage .
Store radiators in such a manner that water cannot
stan d around the sealed openings.
Make a visual inspection of vent and drain plugs to see
if the plugs are tight. If they have been loosened, plugs
must be removed, re-cemented and re-tightened (Teflon
sealing tape may be used for sealing the threads). Store
indoors or in a weatherproof shed. Radiators should be
blocked off the floor if stored three months or more.
Lift individual radiators only by the liftL1g eye on the
top end.
Radiators must be thoroughly inspected prior to as
sembly to be certain that no water or foreign material is
in the oil space. Avoid opening the radiator when it is at
a lower temperature than the ambient in order to prevent
condensation.
If there is any evidence of moisture , the radiator must
be thoroughly dried either by blowing hot air through or
by flushing with hot oil. In any case , it is desirable to
flush out the cooling equipment thoroughly with hot oil
if at all possible . The radiators should be installed on the
transformer the same day they are opened and not permit
ted to stand exposed after opening for inspection or flush
ing. All cooling equipment must be installed prior to final
oil filling. Radiator valves should be closed until imme
diately prior to final vacuum oil-filling. Lock open
all
radiator valves before final vacuum oil filling.
