30
PowerVac
®
5kV Vertical Lift
Chapter 10. Maintenance
10-1 General
PowerVac
®
5kV VL circuit breakers have been
designed to be as maintenance-free as practi-
cable. They include features such as sealed
vacuum interrupters and long-life synthetic
greases which contribute to many years of
trouble-free performance with a minimum
amount of maintenance.
If maintenance on the PowerVac
®
VL breaker is
being performed to an extended schedule such
as a 5-year or 10-year program,
the vacuum
interrupter integrity test should be performed if
the breaker is removed for reasons other than
scheduled breaker maintenance, and it has been
more than one year since the last vacuum in-
tegrity test.
Both long and short term maintenance of all elec-
trical equipment is essential for reliability and
safety. Maintenance programs MUST be custom-
ized to the specific application, well planned,
and carried out consistent with both industry
experience and manufacturer’s recommenda-
tions. The local environment must always be
considered in such programs, including such
variables as ambient temperatures, extreme
moisture, number of operations, corrosive at-
mosphere or major insect problems and any
other unusual or abusive condition of the ap-
plication.
One of the critical service activities, sometimes
neglected, involves the servicing and calibra-
tion of various relay, protection, and control de-
vices. These devices monitor conditions in the
primary and secondary circuits, sometimes ini-
tiating emergency corrective action such as
opening or closing circuit breakers. In view of
the vital role of these devices, it is important
that a periodic test program be followed. As was
outlined above, it is recognized that the interval
between periodic checks will vary depending
upon environment, the type of device and the
user’s experience. It is the General Electric
recommendation that, until the user has accu-
mulated enough experience to select a test in-
terval better suited to his individual require-
ments, all significant relay calibrations should
be checked at an interval of one to two years.
To accomplish this, protective relays can be ad-
equately tested using field test sets. Specific
calibration instructions on particular devices
typically are provided by supplied instruction
books.
Instruction books supplied by manufacturers
address components that would normally re-
quire service or maintenance during the useful
life of the equipment. However, they can not in-
clude every possible part that could require at-
tention, particularly over a very long service
period or under adverse environments. Mainte-
nance personnel must be alert to deterioration
of any part of the supplied switchgear, taking
actions, as necessary, to restore it to service-
able status.
Industry publications of recommended mainte-
nance practices such as ANSI/NFPA 70B, Elec-
trical Equipment Maintenance, should be care-
fully studied and applied in each user’s forma-
tion of a planned maintenance program.
Some users may require additional assistance
from GE in the planning and performance of
maintenance. The local GE office can be con-
tacted to either undertake maintenance or to pro-
vide technical assistance, including the latest
equipment publications.
The performance and safety of this equipment
may be compromised by the modification of
supplied parts or their replacement by non-iden-
tical substitutes. All such design changes
should be qualified by GE factory engineering.
The user should methodically keep written main-
tenance records as an aid in future service plan-
ning and equipment reliability improvement. Un-
usual experiences should be promptly com-
municated to GE.
PowerVac
®
Interrupter
The PowerVac
®
Interrupter used in this breaker
is a reliable, clean interrupting element. Since
the contacts are contained in a vacuum cham-
ber, they remain clean and require no mainte-
nance at any time. The metallic vapors eroded
from the contact surfaces during high current
interruption remain in the chamber and are de-
posited on metal shields thus insuring a high
dielectric value of the vacuum and the walls of
the interrupter.
Trouble Reporting
Although all reputable manufacturers design
their products to perform satisfactorily with a
minimum of problems, the IEEE Switchgear
Committee, an organization of both users and
manufacturers, recognized the need for a com-
mon trouble reporting format. A reproducible
copy of this form is included on pages 66 and
67 of this book and is recommended for use
with any manufacturer’s circuit breakers.
