S280-30-7
9
TEST RESULTS: These high potential withstand tests provide
information on the dielectric condition of the recloser and the vac-
uum integrity of the interrupters.
A. If the recloser passes the closed-contacts tests (Tests 1 and 2)
but fails the open-contacts test (Test 3) a deteriorated vacuum
in one or more of the interrupters is most likely the cause.
Retest each vacuum interrupter individually to determine the
failed phase or phases, and replace the interrupter(s). Retest
to confirm the repair.
B. If the recloser faiIs the closed-contacts tests (Test 1 and 2) the
cause is likely to be a diminished electrical clearance or a
failed insulation. After correcting the problem, retest to con-
firm the repair.
Oil Condition
Oil provides the internal insulation barrier between phases and
from phase to ground, and must be replaced before it deteriorates
below a safe dielectric level. Replace the oil if its dielectric
strength falls below 22 kv.
New oil should always be filtered before use, even though it is
obtained from an approved source. Passing the oil through a blot-
ter press will remove free water and solid contaminants such as
rust, dirt, and lint. Keep aeration to a minimum during filtering to
prevent moisture in the air from condensing in the oil and lower-
ing its dielectric strength.
Used oil must be treated before reusing. Filtering may remove
absorbed and free water and other contaminants to raise the
dielectric strength to acceptable levels. However, filtering does
not always remove water-absorbing contaminants and the dielec-
tric strength may fall rapidly after being returned to service.
Therefore the recloser should be filled with new oil, or oil that has
been restored to like-new condition. Oil used in these reclosers
conforms to ASTM Standard D3487, Type 1; its property limits
are shown in Reference Data R280-90-1, “Oil Specifications and
Tests.”
SHOP MAINTENANCE PROCEDURES
The operations described in this section should be performed
under the cleanest conditions possible. The repair work, except
for bushing replacement, will be simplified if the work bench is
arranged so the mechanism/head assembly can be inverted
(bushings down). No special tools are required for any of the
repair procedures.
Control Lever Overtravel Adjustment
Check for proper adjustment of the control lever by first removing
the sleet hood cover to expose the control lever. From the OPEN
position, slowly push the control lever toward the CLOSED posi-
tion. As the lever is pushed up, latching of the recloser will be felt.
At this point the dimension between the top of the control lever
and the underside of the sleet hood should be 1/4 inch (Figure
12).
If the control lever is not adjusted properly, remove the C-ring
and slide the control lever from the shaft. Rotate the control lever
Figure 12.
Overtravel adjustment of control lever.
clockwise to reduce the dimension or counterclockwise to
increase the dimension. Slide the control lever back onto the
shaft and recheck the dimension. When the proper dimension
has been obtained replace the C-ring.
Bushings
Bushing maintenance generally consists of a thorough cleaning
and a careful examination for chips, cracks, or other mechanical
damage during the periodic maintenance inspection. Bushings
must be replaced whenever damage is discovered.
TYPE VW BUSHINGS
A damaged bushing can be replaced with the
recloser either tanked or untanked, depending
upon the circumstance of the damage.
• If the bushing porcelain is accidentally chipped during installa-
tion of the recloser, and it is obvious that no other damage has
occurred, the bushing porcelain only can be replaced without
untanking the recloser.
• If the bushing has been damaged while in service or storage,
the recloser must be untanked. Water or other contaminants
may have entered the tank (test the oil) the bushing lead may
be damaged (either mechanically or electrical flashover), or
pieces of porcelain may have fallen into the tank.
Replacing the Bushing Porcelain with the Recloser Tanked
Refer to Figure 13 and proceed as follows:
Figure 13.
Replacing bushing w/tanked Type VW recloser.
1. Unscrew bushing terminal and discard terminal gasket.
2. Remove three hex head capscrews and clamps that secure
the bushing to head and lift out porcelain.
3. Remove and discard lower bushing gasket.
4. Twist off split aluminum clamping ring from old porcelain. If it is
in good condition install it on new porcelain; replace if dam-
aged.
NOTE: The clamping ring cushions and distributes the pressure
between the porcelain and the clamps. DO NOT OMIT.
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