3.2 Maintenance
Both long and short term maintenance o f all electrical
equipment is essential for reliability and safety. Mainte
nance programs must be tuned to the specific application,
well planned and carried out consistent with both industry
experience and manufacturer's recommendations. Local
environment must always be considered in such pro
g rams, including such variables as ambient temperatures,
extreme moisture, number of o perations, corrosive atmo
sphere or major i nsect problems and any other unusual or
abusive condition of the application.
One oft he critical service activities, sometimes neglected,
involves the calibration of various control devices. These
monitor conditions in the primary and secondary c ircuits,
sometimes initiating emergency corrective action such as
opening or closing circuit breakers. In v iew of the vital role
of these devices, it is important that a periodic test
program be followed. As was outlined above, it is recog
nized that the i nterval between periodic checks will vary
depending upon environment, the type of device and the
user's experience. It is the General Electric recommenda
tion that, until the user has accumulated enough experience
to select a test interval better suited to h is individual
requirements, all significant calibrations be checked at an
interval of one to two years.
To accom plish this, some items, such as "EC" direct
operating trip systems for low voltage breakers, must be
tested with primary current injection. Others can be
adequately tested using test sets. Specific calibration
instructions on particular devices typically are provided
by supplied instruction books.
I nstruction books supplied by manufacturers address
components that would normally req uire service or main
tenance during the useful life of the equipment. However,
they can not i nclude every possible part that could require
attention, particularly over a very long service period or
under adverse environments. Maintenance personnel
must be alert to d eterioration of any part of the supplied
switchgear, taking actions, as necessary to restore it to
serviceable status.
I ndustry publications of recommended maintenance prac
tices such as ANSI/NFPA 708, Electrical Equipment
Maintenance, should be careful ly studied and applied in
each user's formation of plan ned maintenance.
Some users may require additional assistance from Gen
eral E l ectric in the p l a n n i n g a n d performance of
maintenance. The General Electric Company can be
contracted to either undertake maintenance or to provide
technical assistance such as the latest publications.
The performance and safety of this equipment may be
compromised by the modification of supplied parts or their
replacement by non identical substitutes. All such design
changes must be qualified to ANSI/IEEE Standard C37.59.
The user should methodically keep written maintenance
records as an aid in future service planning and equipment
reliability improvement. Unusual experiences should be
promptly communicated to the General Electric Company.
1 0A
www
. ElectricalPartManuals
. com
