Emerson Liebert NX 50 and 60 Hz - Manual (Page 102)

Operating Procedures
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7.11 Reset After Shutdown for Emergency Stop (EPO Action) or Other Conditions
Once all appropriate measures have been taken to correct the problem indicated by the alarm mes-
sage appearing on the operator control panel display, carry out this procedure to restore the UPS to
regular operation following an EPO action or for the following reasons: Inverter Overtemperature,
Cut-off Overload, Battery Overvoltage, excessive switching (BYP: XFER COUNT BLOCK), etc.
When the user confirms that the fault is cleared & the remote EPO signal is not active:
1. Press the FAULT CLEAR button to let the system exit the Emergency Off state.
2. Press the INVERTER ON button on the right side of the operator control panel for longer than
2 seconds.
After the EPO button is pressed, if the input utility is removed, the UPS will shut down completely.
When input utility returns, if the Bypass input power switch (Q2) and UPS output power switch (Q5)
are closed, the UPS will startup on Bypass. There will be power at the output terminals of the UPS.
7.12 Auto Restart
When the main and bypass sources fail, the UPS draws power from the battery system to supply the
load until the batteries are depleted. When the UPS reaches its end of discharge (EOD) threshold, it
will shut down.
The UPS will automatically restart and enable output power:
• After utility power is restored
• If “Auto Recovery after EOD Enabling” is enabled
• After the “Auto Recovery after EOD Delay Time” expires (the default delay is 10 minutes) .
If the “Auto Recovery after EOD Enabling” feature is disabled, the user may restart the system man-
ually by pressing “Fault Clear” button.
NOTE:
UPS manufactured before March 2006 may first require a full power down, i.e., manual
opening of the input isolators, for the "Fault Clear" to take effect
NOTE
The rectifier will start again, and the bypass will begin to power the load (for units with
internal battery contactor installed, the battery contactor will close). The Rectifier indicator
flashes while the rectifier is starting up. When the rectifier enters the normal operation state
(about 30 seconds), the rectifier indicator turns green.
NOTE
The rectifier will be turned On automatically when the overtemperature fault disappears at 5
minutes after the disappearance of overtemperature signals.
!
WARNING
If the internal Manual Bypass Power Switch (Q3) is closed and input utility is present, there
will be power at the output terminals of the UPS.