Emerson 250-400kVA Manuel D’Utilisation

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.

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.

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.

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.

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)

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400 - 1200 Amps 

300 (34)

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#22 - #14 

3.5 to 5.3 (0.4 to 0.6)

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