31
Any major observed problems should be docu-
mented. Forward the completed user report
forms to GE Resolution at West Burlington,
Iowa.
The intent is for each maintenance organization
to keep specific problem files with this informa-
tion documented. If the problem is serious or
repetitive, a summary should be sent to the ap-
propriate manufacturer for action. The level of
detail included on the form is considered very
desirable so that the manufacturer’s investiga-
tor may more thoroughly understand and solve
the reported problem.
10-2 Service Conditions
The frequency of required maintenance depends
on the severity of the service conditions of the
switchgear application. If the service conditions
are mild, the interval between maintenance op-
erations may be extended to 10 years or 10,000
no load operations or 5000 normal load switch-
ing operations.
Mild service conditions are defined as an envi-
ronment in which the switchgear is protected
from the deleterious effects of conditions such
as:
Salt spray.
Changes in temperature that produce dust
conductive/or abrasive and condensation.
Damaging chemicals and fumes.
Vibration or mechanical shock.
High relative humidity (90%).
Temperature extremes (below -30º C or above
+40º C).
WARNING:
BEFORE ANY MAINTENANCE
WORK IS PERFORMED, MAKE CERTAIN
THAT ALL CONTROL CIRCUITS ARE DE-EN-
ERGIZED AND THAT THE BREAKER IS RE-
MOVED FROM THE METALCLAD UNIT. DO
NOT WORK ON THE BREAKER OR MECHA-
NISM WHILE IT IS IN THE CLOSED POSI-
TION WITHOUT TAKING PRECAUTIONS TO
PREVENT ACCIDENTAL TRIPPING. DO NOT
WORK ON THE BREAKER WHILE THE CLOS-
ING SPRING IS CHARGED UNLESS IT IS SE-
CURED IN THAT POSITION BY THE CLOS-
ING-SPRING GAG.
PowerVac
®
5kV Vertical Lift
Chapter 10. Maintenance
10-3 Fault Interruptions
The erosion rate of the primary contacts in the
vacuum interrupters is very low for no-load and
normal load switching operations. However,
fault current interruptions at or near the breaker
rating may result in appreciable contact erosion.
With frequent fault interruptions, it is neces-
sary to perform maintenance based on the num-
ber of interruptions. After each 20 full fault inter-
ruptions the following should be performed:
1.
Contact erosion check.
2.
Wipe and gap check.
3.
Vacuum interrupter integrity test.
10-4 Contact Erosion
Refer to Chapter 8-1 for contact erosion and con-
tact gap measurements. When erosion reaches
1/8 inch, the interrupter should be replaced.
10-5 Transfer Finger Wear
With the breaker open, examine the moving
contact rod projecting below the transfer fingers
(Figure 23, Item 8). Wipe off the lubricant in
order to see the metal surface condition. The
finger locations should present a burnished sil-
ver contact surface without copper appearance.
If copper is visible at more than one location
per pole or the silver plating is torn, the inter-
rupter assembly should be replaced. After in-
spection, re-lubricate with grease, part #
0282A2048P009 (Mobil 28 red grease).
10-6 Mechanism
Check all items covered in INSTALLATION Chap-
ter 4 and readjust or tighten hardware as re-
quired. Lubricate as recommended under LU-
BRICATION.
10-7 Primary Insulation Parts
Using dry, non-linting cloth or industrial-type
wipers, clean accessible insulation surfaces on
the interrupter supports and operating rod insu-
lators. In service locations, where contamina-
tion is heavy or external flashovers have oc-
curred, or occurance is noted during interrupter
high-potential testing, remove the interrupter
assemblies and clean the inside surfaces of the
interrupter supports and the outer insulation
surfaces of the PowerVac interrupters. Follow
the procedure in REPAIR AND REPLACEMENT,
Chapter 12.
