Emerson 250-400kVA - Manual (Page 43)

Maintenance
37
Rack-Mounted Batteries
If the UPS system uses a battery other than a factory-supplied Matching Battery Cabinet, perform
maintenance on the battery as recommended in the battery manufacturer’s maintenance manual,
available on the manufacturer’s Web site.
3.4.2 Torque Requirements
All electrical connections must be tight. Table 4 provides the torque values for the connections in the
UPS. Use these values unless the equipment is labeled otherwise.
3.5 Detecting Trouble
It is important that the operator check the instrument readings if abnormal equipment performance
is suspected. Any metered value that differs appreciably from normal could mean an impending mal-
function and should be investigated.
Items to check include:
• If the UPS has not operated on battery power during the last 10 hours, the batteries should
require little charging current. Battery mimic should indicate normal DC voltage with the battery
charge current no more than 1% of maximum discharge current.
• Input current on each phase should be within 10% of the average input current.
• Alarm messages indicate malfunction or impending malfunction. A daily check of the Display
Screen will help to provide an early detection of problems. Refer to Table 7 for information about
interpreting alarm messages.
• Tracing a problem to a particular section is facilitated by alarm messages and the metered
parameter indications.
NOTICE
If the UPS system has an open fuse, the cause should be determined before replacing the fuse.
Contact Liebert Services for assistance.
NOTE
Refer to the battery manufacturer’s manual, available on the manufacturer’s Web site, for the proper torque
values required for the battery.
Table 4 Torque specifications, unless otherwise labeled
Nut and Bolt Combinations
Bolt Shaft Size
Grade 2 Standard
lb-in (Nm)
Electrical Connections
with Belleville Washers
lb-in (Nm)
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)
Current Rating lb-in (N-m) —
400 - 1200 Amps 300 (34) —
Circuit Breakers with Compression Lugs (For Control Wiring)
AWG Wire Size or Range lb-in (N-m) —
#22 - #14 3.5 to 5.3 (0.4 to 0.6) —