Maintenance 115
4.4 Detection of Trouble
Thereis no practical way to anticipate an impending malfunction. It is importantthat the operator check the
instrumentreadings if abnormal equipment performance is suspected.
Itemsto check include:
1. Outputvoltage of all phases should be within 2% of normal voltage. Output currents on each phaseshould
notnormally differ by more than 20%. If a greater differenceis noted, the load is unbalanced and corrective
actionshould be taken to redistribute the load, if possible.
2. Ifthe UPS has not operated on battery power during the last 10 hours, the batteries shouldrequire little
chargingcurrent. Battery mimic should indicate normalDC voltage with the battery charge current no more
than31 Amperes.
3. Inputcurrent on each phase should be within 10% of the average input current.
4. Alarmmessages indicate malfunction or impending malfunction.A daily check of the Operator Control
Panelwill help to provide an early detection of problems. Refer to Tabl e 1 andTa ble 2 in 3.0 - Operation
to interpret alarm me ssages.
5. Tracing a problem to a part icular section is facilit ated by alarm messages and t he metered parameter
indications.These are stored in the Status Reportsa ndcan be displayed at the Operator Control Panel or at
anoptional terminal. The Liebert Customer Service Engineer will alsobe familiar with test points inside the
unit.
Table4 TorqueSpeci fications (Unless Otherwise Labeled)
Nut and Bolt Combinations
Bolt
Shaft
Size
Grade 2
Standard
Electrical Connections
withB ellevilleWashers
Lb-in N-m Lb-in N-m
1/4 53 6.0 46 5.2
5/16 107 12 60 6.8
3/8 192 22 95 11
1/2 428 48 256 29
Circuit Breakers With Compression Lugs
(For Power Wiring)
Terminal Block Compression Lugs
(For Control Wiring)
Current
Rating Lb-in N-m
AWGWire
Sizeor
Range Lb-in N-m
400- 1200
Amps
300 34 #22- #14 3.5to 5.3 0.4to 0.6
NOTE
Ifthe UPS system has a blown fuse, the cause should be determinedbefore you
replacethe fuse. Contact Liebert Global Services.
DISCONTINUED
PROD U C T