GE Industrial Solutions AKD-20 Low Voltage Switchgear - Manuel (Page 58)

AKD-20 Low Voltage Switchgear
Chapter 9. Maintaining the Switchgear
58 ©2012 General Electric All Rights Reserved
9-1 Maintenance Requirements
General
A periodic maintenance schedule must be established to obtain
the best service from the switchgear. An annual check of the
switchgear devices and all connections should be made as a
minimum requirement. Equipment subject to highly repetitive
operation may require more frequent maintenance.
A permanent record of all maintenance work should be kept.
The record should include a list of periodic checks and tests
made, the date they were made, the condition of the equipment,
and any repairs or adjustments that were performed.
Maintenance employees must follow all recognized safety
practices, such as those contained in NFPA 70B: Electrical
Equipment Maintenance, and NFPA 70E: Standard for
Electrical Safety in the Workplace and in company or other
safety regulations.
WARNING: Solid insulation surrounding an energized
conductor and power apparatus must never be relied upon to
provide protection to personnel.
ADVERTISSEMENT: Il ne faut pas se fier à une isolation solide
entourant un conducteur mis sous tension et à la puissance
de l’appareillage pour fournir une protection aux membres du
personnel.
For specific information regarding the maintenance of devices,
such as circuit breakers, relays, meters, etc., refer to the
separate instruction book furnished for each device.
9-2 Breaker and Instrument
Compartments
Periodic inspection of the circuit breaker is recommended at
least once a year. More frequent inspections are recommended
where severe load conditions, dust, moisture or other
unfavorable conditions exist, or if the vital nature of the load
warrants it. Always inspect the breaker after a short-circuit
current has been interrupted.
Breakers
Test for Proper Operation
Test and inspect all circuit breakers for proper operation as
follows:
1. Operate each breaker while in the TEST position and check
all functions. This is particularly important for breakers
that normally remain in either the opened or closed
positions for long periods of time.
WARNING: Primary equipment must be completely de-
energized while tests on control circuits, etc. are being
conducted. Be sure that all areas of feedback from
secondary circuits, as well as outside sources, are
disconnected.
ADVERTISSEMENT: Il faut que l’équipement primaire soit
complètement désamorcé lorsque des tests sont effectués
sur des circuits de contrôle, etc. Assurez-vous que toutes les
aires de rétroaction des circuits secondaires de même que les
sources extérieures soient débranchées.
2. Remove the breakers from their compartments to a clean
maintenance area. Close compartment door and cover
the breaker cutout to prevent access to live parts.
WARNING: De-energize equipment completely before doing
maintenance work on any devices, connections, bus work,
breaker or feeder cable compartments. This includes de-
energizing any connections to outside primary or secondary
sources, such as transformers, tie lines, etc.
ADVERTISSEMENT: Désamorcer complètement l’équipement
avant d’effectuer du travail de maintenance dans les
compartiments. Cela inclut le désamorçage de toute
connexion aux sources primaires et secondaires, telles que
les transformateurs et les interconnexions.
Checks After Breaker Is De-energized
At the time of inspection, the following checks should be made
after the breaker has been de-energized.
1. Manually operate the breaker several times, checking for
obstructions or excessive friction. Manual closing of an
electrically operated breaker may be performed by the
following two steps:
a. To charge the mechanism springs, pull the operating
handle down until it stops (about 90°) ten times for the
Entelliguard G breaker. The charge indicator will show
CHARGED on a yellow background.
b. Depress the CLOSE button on the front of the breaker.
The springs should discharge and, if the latch is
properly reset, the breaker will close.
2. Electrically operate the breaker several times to check
performance of the electrical accessories.
3. Visually check the breaker for loose hardware on the
breaker; also, check the bottom of the compartment for
any hardware that has fallen from the breaker.
4. Remove and inspect the arc quenchers and contacts for
breakage or excessive burning.
5. The performance of the solid-state current trip devices
may be checked with a suitable test set. Check electro-
mechanical devices for positive trip in accordance with the
instructions in the proper Maintenance Manual.
6. Check insulating parts for evidence of overheating and for
cracks that indicate excessive thermal aging.
Refer to circuit breaker instruction manuals for detailed
maintenance instructions and information for replacement of
parts. See DEH-41304.