Liebert 610 - Manual (Page 48)

Operation
42
3.2.7 Load Transfer Procedures Screen
Go to the Master Menu and move the highlighted cursor to LOAD TRANSFER PROCEDURES. Press
the Select pad and the Load Transfer Procedures screen is displayed.
Figure 30 Load transfer procedure screen
The Load Transfer Procedures screen contains instructions to transfer the critical load between the
UPS system and the bypass line. Comparisons of the UPS and bypass voltage, frequency and phase
synchronization are displayed along with transfer status messages. The metered parameter values on
the Load Transfer Procedures screen are updated at half-second intervals.
Refer to 3.3 - Modes of Operation and 3.4.2 - Load Transfer Procedures for more details.
Item 1 - Voltage Comparisons: This chart shows the UPS and bypass voltage and frequency com-
parisons between each of the three phases. If the UPS and bypass voltages are not within specified
tolerances, a manual transfer is not permitted and TRANSFER PROHIBIT is highlighted.
The Voltage Adjust knob (push-to-turn), located on the Operator Control Panel (Figure 4), is used
to match the UPS output voltage to the bypass voltage. When the UPS and bypass voltages match
within the specific tolerance, a manual transfer is possible and OK TO TRANSFER is highlighted.
Item 2 - Synchronization: This display shows the phase synchronization between the UPS output
and bypass power. If the phase displacement is outside of the tolerance, a manual transfer is not per-
mitted and TRANSFER PROHIBIT is highlighted.
During normal operation, the synchronization display should read UPS LEAD from zero to 4 degrees.
Item 3 - Status Messages: Three messages are constantly displayed here. Only the active message
is highlighted. If TRANSFER PROHIBIT is highlighted, manual transfers/retransfers cannot be per-
formed and automatic retransfers will not be initiated.
Item 4 - Manual Transfer Instructions: These instructions assist the operator in transferring the
critical load between the UPS system and the bypass line.
If the load is on the bypass line, step 2 on the screen will instruct you to press the UPS and Control
Enable buttons to retransfer the load from the bypass line to the UPS system.
!
CAUTION
The UPS output voltage responds very slowly to inputs from the Voltage Adjust knob. Make
small adjustments and wait several seconds each time for voltage to stabilize before
continuing.
TRANSFER PROHIBIT
UPS LEAD = 2 Deg
UPS -
BYPASS -
480 480
480 481
B-C A-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
1
2
4
3