2 torque requirements, 5 detection of trouble, Torque requirements – Liebert 1000kVA User Manual

Page 112: Detection of trouble, Table 15, Torque specifications (unless otherwise labeled)

Maintenance

106

4.4.2 Torque Requirements

All electrical connections must be tight. Table 15 provides the torque values for the connections in

the UPS. Use these values unless the equipment is labeled otherwise.

4.5

Detection of 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:

• Output voltage of all phases should be within 2% of normal voltage. Output currents on each

phase should not normally differ by more than 20%. If a greater difference is noted, the load is

unbalanced and corrective action should be taken to redistribute the load, if possible.

• 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 31 Amperes.

• 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 Operator

Control Panel will help to provide an early detection of problems. Refer to Table 9 and Table 10

to interpret alarm messages.

• Tracing a problem to a particular section is facilitated by alarm messages and the metered

parameter indications. These are stored in the Status Reports and can be displayed at the Opera-

tor Control Panel or at an optional terminal. A Liebert Global Services engineer will be familiar

with test points inside the unit.

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 15

Torque specifications (unless otherwise labeled)

Nut And Bolt Combinations

Bolt Shaft Size

Grade 2

Standard

Electrical Connections

with Belleville Washers

Lb-in

N-m

Lb-in

N-m

1/4

6.0

5.2

5/16

107

6.8

3/8

192

1/2

428

256

Circuit Breakers with Compression Lugs (For Power Wiring)

Current Rating

Lb-in

N-m

400 - 1200 Amps

300

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

NOTE
If the UPS system has a blown fuse, determine the cause should be determined before replacing

the fuse. Contact Liebert Global Services for assistance.