Liebert STS2 - Manual (Page 84)

Operating Instructions
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4. Close CB1.
5. Verify that Source 1 voltages are nominal and that CB1 breaker status is correctly indicated on
the Monitor/Mimic screen.
6. Close CB2.
7. Verify that Source 2 voltages are nominal and that CB2 breaker status is correctly indicated on
the Mimic screen.
8. Verify that boxes for the preferred source and corresponding Static Transfer Switch 2 Power
Distribution Unit are highlighted on the Mimic screen, indicating which side of the Static
Transfer Switch 2 Power Distribution Unit is on.
9. Close Output Breaker CB3 (for redundant output configurations, also close CB3A).
10. Verify that CB3, the Output box and the Load box are highlighted, indicating that CB3 is closed
and the STS output is energized. On units with I-line panelboard, the panelboard is also
energized.
11. Press the RESET button on the touch screen to reset any previous alarms.
12. Check the Event Display and the Mimic to verify there are no active alarms. If any active alarms
are displayed, refer to 11.0 - Alarms and Faults for a description of the alarms and possible
causes. Correct all active alarm conditions before proceeding.
13. If unit is equipped with output breaker CB8, close CB8. The output and load are energized.
14. If unit is equipped with output inline panelboards, close panelboard main breakers CB8 and CB9
and, if supplied, CB10 and CB11. Turn on panelboard breakers. If optional subfeed breakers are
supplied, close subfeed breakers CB12 and CB13.
15. Turn on the load equipment as directed in the load equipment manufacturer’s recommendations.
10.2 Manual Transfer / Preferred Source Selection
The Source Transfer option (Source Xfers) in the touch screen menu allows you to select a preferred
source. Transfers are only permitted when the voltage and current are within their proper operating
range and the sources are synchronized. The Source Transfer screen indicates the synchronization
between the two sources, while the voltage and frequency are displayed on the Mimic. See Figure 60.
Transfer is inhibited if the deviation exceeds the parameter set in Source Setpoints. See User
Settings on page 101.
NOTE
For redundant output configurations, CB3 descriptions apply to CB3 and CB3A.
NOTE
If one source will be de-energized for an extended period (hours or days), set the STS2/PDU to
bypass mode for the remaining source. Without using bypass, if a failure occurs in the switch
components for the remaining source, the STS2/PDU does not have a second source to switch
to and the load would not receive power. See 14.2.12 - Maintenance Bypass for bypass
instructions.