Introduction
ONLY qualified service personnel should perform maintenance on the UPS system. When performing maintenance with any part of the equipment under power, service personnel and test equipment should be standing on rubber mats. The service personnel should wear insulating shoes for isolation from direct contact with the floor (earth ground).
Unless all power is removed from the equipment, one person should never work alone. A second per- son should be standing by to assist and summon help in case an accident should occur. This is partic- ularly true when work is performed on the battery.
Three types of messages are used throughout the manual to stress important text. Carefully read the text below each Warning, Caution, and Note and use professional skills and prudent care when per- forming the actions described by that text.
A Warning signals the presence of a possible serious,
! WARNING
Lethal voltages may be present within this unit even when it is apparently not operating. Observe all cautions and warnings in this manual. Failure to do so could result in serious injury or death. Do not work on or operate this equipment unless you are fully qualified to do so! Never work alone.
A Caution indicates a condition that could seriously damage equipment and possibly injure personnel. For example:
! CAUTION
Make sure you understand the proper sequence before operating any circuit breaker. Operating a Maintenance Bypass circuit breaker out of sequence could cut off power to the critical load.
A Note emphasizes important text. If the note is not followed, equipment could be damaged or may not operate properly. For example:
NOTE
If the UPS system has a blown fuse, the cause should be determined before you replace the fuse. Contact Liebert Global Services.
1.3Modes Of Operation
Refer to 2.0 - Theory of Operation and 3.0 - Operation for more details.
1.3.1Normal (Load On UPS)
The utility AC source provides power to the rectifier/charger in the UPS module. The rectifier/charger converts the utility AC power to DC and supplies DC power to the UPS module inverter while simul- taneously float charging the battery plant. The UPS inverter converts DC to AC and furnishes AC power to the critical bus.
1.3.2Input Power Failure
If the utility source power fails or is outside the acceptable range, the battery plant becomes the pri- mary supplier of DC power to the inverter.
1.3.3Recharge
After the utility source power is restored, or an alternate power source becomes available, the recti- fier/charger slowly
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