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Operation 97
3.3.2 Load Transfer Procedures
Use the Monitor/Mimic Display at the SCC to determine the operating condition of the UPS system. Press the
Alarm Reset pad to clear the Alarm Messages. Refer to Table 1 for an explanation of any remaining alarm mes-
sages (except Load On Bypass). Call Liebert Global Services if you cannot clear the remaining alarm messages.
If the only alarm message displayed is Load On Bypass (or no alarms), you can perform a manual transfer of the
load between the UPS system and the UPS bypass line. Changing the load from the UPS system to the UPS
bypass is called a transfer. Changing the load from UPS bypass to the UPS system is called a retransfer. Note
that the UPS system control logic can initiate automatic load transfers and retransfers. Refer to 3.4 - Automatic
Operations.
Press the Select pad to display the Master Menu on the LCD display of the SCC. Move the highlighted cursor to
Load Transfer Procedures (using the Up and Down pads). Press the Select pad to display the Load Transfer Pro-
cedures screen.
Step 1. Verify that the OK TO TRANSFER message is highlighted. If not (if the TRANSFER PROHIBIT
message is highlighted instead), slowly rotate the Voltage Adjust knob (Figure 10, item 6) to match the UPS
system voltage to the bypass voltage.
Figure 61 Load Transfer Procedures Screen
Step 2. Perform Step 2 on the Load Transfer Procedures Screen.
a. IftheloadisontheUPSsystem,simultaneously press the Bypass and Control Enable pads
(Figure 10). This will close the motorized System Bypass circuit breaker (SBB) and open the
motorized UPS Output circuit breaker in a make-before-break sequence.
b. If the load is on the UPS bypass, simultaneously press the UPS and Control Enable pads (Figure 10).
This will close the motorized UPS Output circuit breaker and open the motorized System Bypass circuit
breaker (SBB) in a make-before-break sequence.
Return to the Monitor/Mimic Display screen to monitor the operation of the UPS system. Press the Alarm Reset
pad to clear any latched alarm messages removed by the new load status. Refer to Table 1 if an alarm message
other than Load On Bypass is still displayed. Contact Liebert Global Services if you require assistance.
NOTE
1. UPS output voltage changes VERY slowly in response to movements of the
Voltage Adjust knob. To avoid overshooting, allow at least a minute for UPS
output voltage to stabilize before proceeding to the next step.
2. If the TRANSFER PROHIBIT message remains, refer to Table 1 for corrective
action for any alarm messages. Call Liebert Global Services if you cannot solve
the problem.
TRANSFERPROHIBIT
UPS LEAD = 2 Deg
UPS -
BYPASS -
380380
380381
B-CA-B
VOLTAGE COMPARISON
SELECT : MASTER MENU
OK TO TRANSFER
+30
ONUPS
50.0 Hz
379
C-A
FREQUENCY
MANUAL
TRANSFER INSTRUCTIONS
1. Adjustthe UPS voltage until it equalsthe
bypass voltagewith the VOLTAGE ADJUST pot.
2. If the OKTO TRANSFERmessageis highlighted,
simultaneouslypress theBYPASS andCONTROLENABLE
buttons.
3. Verify that the transfer was successful by checking the
breaker status on the "MONITOR/MIMIC" screen.
4. Press the ALARM RESET button to clear alarms which
are no longeractive
SYNCHRONIZATION
50.0 Hz
0-30
380