Operation
74
3.4.2 Load Transfer Procedures
Use the Monitor/Mimic Display to determine the operating condition of the UPS module. Press the
Alarm Reset pad to clear the Alarm Messages. Refer to Table 4 for an explanation of any remaining
alarm messages (except Load On Bypass). Call Liebert Global Services if you cannot clear the remain-
ing 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 module 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 3.5 - Automatic Operations.
STEP 1 (Load Transfer Procedures)
a. Press the Select pad to display the Master Menu on the LCD. Move the highlighted cursor to
Load Transfer Procedures (using the Up and Down pads). Press the Select pad to display
the Load Transfer Procedures screen.
b. 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 (see
Figure 4) to match the UPS system voltage to the bypass voltage.

Figure 54 Load transfer procedures screen

STEP 2 (Load Transfer Procedures)
Perform Step 2 on the Load Transfer Procedures Screen.
a. If the load is on internal bypass, simultaneously press the UPS and Control Enable
pads (Figure 4). This will close the motorized UPS module output circuit breaker and open
the motorized UPS bypass circuit breaker in a make-before-break sequence.
b. If the load is on the UPS module, simultaneously press the Bypass and Control Enable
pads (Figure 4). This will close the motorized bypass circuit breaker and open the motorized
UPS module output circuit breaker in a make-before-break sequence.
Return to the Monitor/Mimic Display screen to monitor the operation of the UPS module. Press the
Alarm Reset pad to clear any latched alarm messages removed by the new load status. Refer to
Table 4 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 Table4 for corrective action for
any alarm messages. Call Liebert Global Services if you cannot solve the problem.
TRANSFER PROHIBIT
UPS LEAD = 2 Deg
UPS -
BYPASS -
480480
480481
B-CA-B
VOLTAGE COMPARISON
SELECT : MASTER MENU
OK TO TRANSFER
+30
ON UPS
60.0 Hz
479
C-A FREQUENCY
MANUAL
TRANSFER INSTRUCTIONS
1. Adjust the UPS voltage until it equals the
bypass voltage with the VOLTAGE ADJUST pot.
2. If the OK TO TRANSFER message is highlighted,
simultaneously press the BYPASS and CONTROL ENABLE
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 longer active
SYNCHRONIZATION
60.0 Hz
0-30
480
ON BYPASS
Adjust the UPS voltage until it equals the
bypass voltage with the VOLTAGE ADJUST pot.
If the OK TO TRANSFER message is highlighted,
simultaneously press the UPS and CONTROL ENABLE
buttons.
Verify that the transfer was successful by checking the
breaker status on the "MONITOR/MIMIC” screen.
Press the ALARM RESET button to clear alarms which
are no longer active.