Emerson 250-400kVA - Manual (Page 42)

Maintenance
36
Because individual battery characteristics are not identical and may change over time, the UPS mod-
ule is equipped with circuitry to equalize battery cell voltages. This circuit increases charging voltage
to maintain flooded type battery cells at full capacity.
Matching Battery Cabinets—Optional
Although the individual battery cells are sealed (valve-regulated) and require only minimal mainte-
nance, the Battery Cabinets should be given a periodic inspection and electrical check. Checks should
be performed at least annually to ensure years of trouble-free service.
Voltage Records: With the Battery Cabinet DC circuit breaker closed and the connected UPS oper-
ating, measure and record battery float voltage. With the DC circuit breaker open, measure and
record the nominal (open circuit) voltage. Both these measurements should be made across the final
positive and negative terminal lugs. Compare these values with those shown below. The recorded
nominal voltage should be no less than the value shown; while the recorded float voltage should be
within the range shown. If a discrepancy is found, contact Liebert Services.
Power Connections: Check for corrosion and connection integrity. Visually inspect wiring for dis-
colored or cracked insulation. Clean and/or retighten as required. Refer to torque specifications in
Table 4.
Battery Cell Terminals: Check for discoloration, corrosion and connection integrity. Clean and
tighten if necessary. Note that when installing a new battery, the initial torque value is 5 lb.-in. more
than the retorque value. Table 8 shows battery retorque values.
If you have a different model battery, contact Liebert Services for the required torque value.
To access battery cell terminals, disconnect the inter-tier cable and two shelf retaining screws. Once
disconnected, insulate (with protective boot or electrical tape) the cables to prevent accidental shorts.
The battery shelf can now be pulled out. Tighten each terminal connection to the retorque value.
When replacing a battery, the terminal connections must be cleaned and tightened. Disconnect and
insulate the cables connected to the battery. Secure each battery shelf with retaining screws when
maintenance is complete.
!
WARNING
Risk of electric shock, explosive reaction, hazardous chemicals and fire. Can cause equipment
damage, personal injury and death.
Do not use equalize charging with valve-regulated, lead-acid batteries. Refer to the battery
manufacturer’s manual, available on the manufacturer’s Web site, for specific information
about equalize charging.
Table 2 Battery voltage, nominal and float
Number of Cells
Battery Voltage, VDC
Nominal Float
240 480 527 - 552
Table 3 Battery retorque values
Battery
Manufacturer
Battery Model
Number
Retorque
Value
C&D batteries
UPS12-300MR 110 in-lb
UPS12-350MR 110 in-lb
UPS12-400MR 110 in-lb
UPS12-490MR 110 in-lb
UPS12-540MR 110 in-lb
Enersys
HX205-FR 65 in-lb
HX300-FR 65 in-lb
HX330-FR 65 in-lb
HX400-FR 65 in-lb
HX500-FR 65 in-lb