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12.0 M
AINTENANCE
12.1
Safety Precautions
Observe the safety precautions in Important Safety Instructions on page 1.
Only properly trained and qualified personnel should perform maintenance on the UPS system.
Observe all of the warnings and cautions below before performing any maintenance on the UPS
system and associated equipment. Also observe the manufacturer's safety precautions pertaining to
the battery, along with the battery safety precautions in this section.
WARNING
!
Risk of electrical shock and arc flash. Can cause property damage, injury and death.
Only Emerson or Emerson-trained service personnel should work on this equipment. Both AC
and DC high voltages are present in lethal amounts within this equipment. Extreme care
should be taken when working around UPS equipment.
Always identify the source of connecting wiring prior to disconnecting. Mark any disconnected
wires, so they can be properly reconnected.
Do not substitute parts except as authorized by Emerson.
Maintain the UPS cabinets free of foreign materials such as solder, wire cuttings, etc.
Call Liebert Services if you are not sure of the procedures to follow or if you are not familiar
with the design or operation of the equipment.
WARNING
!
Risk of electrical shock and arc flash. Can cause property damage, injury and death.
Extreme caution is required when performing maintenance.
Be constantly aware that the UPS system contains high DC as well as AC voltages. With
input power off and the battery disconnected, high voltage at filter capacitors and power
circuits should be discharged within 30 seconds. However, if a power circuit failure has
occurred, you should assume that high voltage may still exist after shutdown. Check with a
voltmeter before making contact.
AC voltage will remain on the bypass and output contactors and the static bypass switch,
unless associated external circuit breakers are opened.
Check for voltage with both AC and DC voltmeters prior to making contact.
When the UPS system is under power, both the operator and any test equipment must be
isolated from direct contact with earth ground and the UPS chassis frame by using rubber
mats.
Some components within the cabinets are not connected to chassis ground.
Any contact between floating circuits and the chassis is a lethal shock hazard. use differential
oscilloscopes when measuring a floating circuit. The differential input should have at least
800 vrms common mode input rating and a common mode rejection ratio of at least 8odb.
Exercise caution that the test instrument exterior does not make contact either physically or
electrically with earth ground.
In case of fire involving electrical equipment, use only carbon dioxide fire extinguishers, or
others approved for use in electrical fire fighting.
123
Maintenance
®
™
Liebert
APM
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