Liebert 1000kVA Operation & Maintenance Manual page 91

Step 1. Before you apply power to the UPS modules, determine the position of the following circuit
breakers and switches:
a. Bypass Input Breaker (BIB) - If this circuit breaker is closed, you may already have power
to the critical load through the bypass line. If this breaker is closed, leave it closed. If it is
open, leave it open until you are ready to energize the bypass line.
b. System Bypass Circuit Breaker (SBB) - This motorized circuit breaker (Figure 9) should
be closed unless you are recovering from a Remote Emergency Power Off. You may already be
supplying power to the critical load through this breaker. If this breaker is open, you will be
instructed to reset it later in this procedure.
c. UPS Output Circuit Breaker - This motorized circuit breaker (see Figure 9) should be
open.
d. Static Switch Disconnect - This manually operated disconnect (see Figure 9) will be in the
ON (closed) position unless you are recovering from a shutdown. If the disconnect is OFF
(open), you will be instructed to reset it and turn it on later in this procedure.
NOTE
Depending on SCC model, the static switch disconnects can be one or two circuit breakers or
two contactors. The location could be at the front, right or rear of the cabinet. Refer to the
drawing of the SCC cabinet selected for your UPS system.
NOTE
If the system was shut down in response to an "Emergency Off, there may be alarm messages on
the LCD screen that describe system conditions before (or at the time of) the shutdown. Some or
all of the alarm conditions may have already been resolved. To clear these alarm messages,
turn off the control power (see Figure 8 and Figure 9). Wait at least 10 minutes for the control
power circuitry to completely de-energize. After 10 minutes, turn control power back on and
wait two minutes before continuing.
e. Control Power - The fuses for the SCC control power (labeled F7 through F10, located below
the SCC control boards in Figure 9) should be ON (pushed in) unless you are recovering from
a maintenance shutdown. If control power is OFF (fuseholders pulled open), leave it OFF
until you are ready to apply power to the UPS controls.
CAUTION
!
If you are recovering from a UPS system shutdown for maintenance procedures, verify that all
of the SCC doors are closed and latched. All test equipment must be removed from the system.
All electrical connections must be secure.
Power must be provided to the UPS controls so the operator can use the LCD and so the system logic
can perform its control functions. Note that you can use the LCD to monitor UPS system status, even
when the UPS modules are not operating.
During a start-up procedure, power is supplied to the critical load through the UPS (internal) bypass
line while the UPS modules are being energized. Depending on the reason for your UPS system shut-
down, you may already have power through the bypass line. You can determine this by observing the
Monitor/Mimic Display screen at the System Control Cabinet (SCC).
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Operation