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UPS for 400 Vac Grid, User Guide, doc. rev. 4
5.
Emergency Power off – EPO (manual)
An external Emergency Power off (EPO) switch may be installed on the UPS by the customer. The
EPO switch is used to cut power to the load in emergency situations. The switch or push button
must be a normally open type.
For detailed information, refer to the Installation Guide of the system.
5.1.
Power-off button (POB)
Power-off button (POB) can be used to shut down the UPS. Once pressed, this simple N.O. switch
turns off the UPS output. If a battery output breaker is wired to the LVD of the UPS, the battery
DC will also be reduced. The POB connects to the terminal P11 of the static switch, similar to an
EPO. Available as an add-on kit, the POB may be mounted anywhere on the front door of the UPS
by simply cutting out an H frame in the honeycomb vented front door.
WARNING!
POB IS NOT EPO AND CANNOT BE USED IN EMERGENCIES.
5.2.
EPO indication
Any of the output dry contacts can be assigned to indicate when the EPO switch has been
activated. The output dry contact can be used to trigger an external circuit if desired, such as a
lamp or an audible alarm. The LCD displays a shut down by EPO and provides a visual and audible
indication.
5.3.
Battery trip coil dry contact
The UPS’s trip coil terminals are intended to be connected in series to the trip coil of the battery
circuit breaker. When this is done and the EPO switch is activated, the UPS closes a relay that can
be combined with a voltage source to activate the battery trip coil, causing the battery circuit
breaker to turn OFF. If the battery circuit breaker trip coil is rated for 48 VDC, the power supply
can be provided directly by the UPS.
Use of the battery trip coil means that not only will use of the EPO switch cut all AC output from
the UPS, it will also switch off the battery circuit breaker.
