Specifications

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In the event that the critical load must be transferred to the bypass source due to
an overload, the UPS system logic shall monitor the overload condition and, upon
the overload being cleared, perform an automatic re-transfer back to the inverter
output. The UPS system logic shall only allow a re-transfer to occur three times
within a one minute period. Re-transfers shall be inhibited on the fourth transfer
due to the likely hood of a recurring problem at the UPS load distribution. The re-
transfer of load to the inverter shall also be inhibited due to the limitations set in
section 3.3. All retransfers will be inhibited if the inverter and static bypass line
are not synchronized.
4.3.3 Manual Transfers
The UPS shall be capable of transferring the critical load to/from the bypass
source via the front control panel. current to the inverter. Manual transfers will be
inhibited if the inverter and static bypass line are not synchronized.
4.3.4 Static Switch
The static switch shall be a high speed transfer device comprised of naturally
commutated SCR's.
5.0 OPERATOR CONTROL PANEL
5.1 Operator Controls
The operator control panel shall employ the use of a touch screen interface which allows
lock-out of all UPS control functions for security (the Emergency Power Off function
shall not be locked-out). The operator interface shall provide the following:
a. UPS start-up procedure
b. UPS shutdown procedure
c. Emergency Power Off (EPO)
d. Audible alarm silence
e. System status levels
5.2 Remote Operation
Certain UPS controls shall, as standard equipment, be capable of being operated from a
remote location. The remote functions are provided for user convenience and shall be
activated via, user supplied, external dry contact switches connected at the user interface
wiring terminal. The following remote control functions shall be provided as a
minimum: