92 Operation
Powermust be provided to the UPS controls so the operatorcan use the LCD display and so the system logic can
performits control functions. Note that you can use the LCD display to monitor UPS systems tatus,even when
theUPS modules are not operating.
Duringa start-up procedure, power is supplied to the criticalload through the UPS (internal) bypass line while
theUPS modules are being energized.De pendingon the reason for your UPS system shutdown,you may already
havepower through the bypass line. You can determinethis by observing the Monitor/Mimic Display screen at
theSystem Control Cabinet (SCC).
Step 2. If the bypass line is not supplying the load, theLCD screen will be blank. Energize the bypass line by
operatingthe following controls:
a. Closethe Bypass Input Breaker (BIB). This breaker may be in your MaintenanceBypass cabinet.
b. Observethe Monitor/Mimic Display screen to determineif your System Bypass circuit breaker (SBB)
isclosed and whether the UPS Bypass line is supplying power to the criticalload.
Ifyour System Bypass circuit breaker is open (as in recovering from an Emergency Power Off or Low
BatteryShutdown), close this circuit breaker as follows:
b1. Openthe SCC control panel door and find the Transfer Relay Board (Figure 11 ).If the red LED
(CR18)labeled TOT S/D (TotalShutdown) is on, press the Bypass Reset swi tch (SW1) on this
board.The red LED should turn off.
b2. Setthe Static Switch Disconnects (Figu re 9)OFF (open).
NOTE
Ifthe system was shut down in response to an “EmergencyOff, there may be alarm
messageson the LCD screen that describesystem conditions before (orat the time of)
theshutdown. Some or all of the alarm conditions may have alreadybeen resolved.
Toclear these alarm messages, turnoff the control power (see Figure 8 and
Figure9). Wait at least ten minutes forthe control power circuitry to completely de-
energize.After ten minutes, turn controlpower back on and wait two minutes before
continuing.
CAUTION
Ifyou are recovering from a U PS system shutdown for maintenance procedures,
verifythat al l of the SCC doors are closed and latched. All test equipment must
be removed from the system. All elect rical connections must be secure .
NOTE
Waittwo minutes after applying bypasspower before you operate any other UPS
controls.
CAUTION
DO NOT assume that the UPS System Bypass Breaker (SBB) is closed.
Instructions for operating the Maintenance Bypass circuit breakers are on the
MaintenanceBypass cabinet.
Make sure you understand the proper sequence before operating a ny circuit
breaker.Operating a Maintenance B ypass circuit breaker out of sequence could
cutoff power to the critical load.
NOTE
Dependingon SCC model, the static switch disconnects can be two circuitbreakers,
contactorsor plug-in connections on a drawout carriage assembly.The location
couldbe at the front, right, or rear ofthe cabinet. Refer to the drawing of the SCC
cabinetselected for your UPS system.
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PROD U C T