GE Industrial Solutions PowerVac PV-VL 13.8-1000-0 and -1 - Manual (Page 66)

Page 66 GEH 6468A - Power/Vac VL Breaker
20.4. BREAKER COMPARTMENT
MAINTENANCE
GENERAL A regular maintenance schedule
should be established to obtain the best service
and reliability from the breaker compartment. Plant
operating and local conditions will dictate the
frequency of inspection required. For specific
information regarding the maintenance of devices,
relays, meters, etc., refer to the separate
instruction book furnished for each device. The
breaker testing device, which may be furnished as
an option, provides a convenient means for
maintaining the circuit breaker. Under normal
conditions the protective relays do not operate,
therefore, it is important to check the operation of
these devices regularly.
A permanent record of all maintenance work
should be kept, the degree of detail depending on
the operating conditions. In any event, it will be a
valuable reference for subsequent maintenance
work and for station operation. It is recommended
that the record include reports of tests made, the
condition of equipment and repairs and
adjustments that were made.
WARNING: BEFORE ANY COVERS ARE
REMOVED OR ANY DOORS ARE OPENED
WHICH PERMIT ACCESS TO THE PRIMARY
CIRCUITS, IT IS ESSENTIAL THAT THE
CIRCUIT OR CIRCUITS BE DE-ENERGIZED
AND BREAKERS BE WITHDRAWN TO A
DISCONNECTED POSITION, AND TAGGED.
IF WORK IS TO BE DONE ON REMOTE
EQUIPMENT CONNECTED TO A UNIT, THE
BREAKER FOR THAT UNIT SHOULD BE
PLACED IN THE DISCONNECTED POSITION
AND TAGGED. ALSO, REMOTE EQUIPMENT
SHOULD BE ISOLATED FROM ANY OTHER
POWER SOURCES CONNECTED TO IT.
The primary circuits of the equipment are insulated
in order to reduce the size of the equipment.
However, this insulation, except in one of two
instances, requires a certain amount of air gap
between phases and to ground to complete the
insulation. Inserting any object in this air space,
when equipment is energized, whether it be a tool
or a part of the body, may under certain
conditions,
in effect, short circuit this air gap and may cause a
breakdown in the primary circuit to ground and
cause serious damage or injury or both.
Care should be exercised in the maintenance and
checking procedures that accidental tripping or
operation is not initiated.
The equipment and connections should be given
the following overall maintenance at least annually.
1. Thoroughly clean the equipment, removing all
dust and other accumulations. Wipe clean the
buses and supports with a clean cloth and de-
natured alcohol. Inspect the buses and connections
carefully for evidence of overheating or weakening
of the insulation.
2. Measure the resistance to ground and between
phases of the insulation of buses and connections.
Since definite limits cannot be given for
satisfactory insulation resistance values, a record
must be kept of the reading. Weakening of the
insulation from one maintenance period to the next
can be recognized from the recorded readings. The
readings should be taken under similar conditions
each time, and the record should include the
temperature and humidity.
Hi-potential tests are not required, but if it seems
advisable, based on the insulation resistance tests
or after repairs, the test voltage should not exceed
27kV AC. These voltages are 75% of the factory
test voltages and are in accordance with ANSI
standards.
Potential transformers and control power
transformers must be disconnected during high
voltage testing.
3. Clean elevating mechanism and lubricate.
4. Check primary disconnecting device contacts
for signs of abnormal wear or overheating. Clean
contacts with de-natured alcohol.
Discoloration of the silvered surfaces is not
ordinarily harmful unless atmospheric conditions
cause deposits, such as sulfides, on the contacts.
If necessary, the deposits can be removed with a
good grade of silver polish.