Liebert NX UPS System user manual Emergency Shutdown With EPO, Auto Restart

Models: NX UPS System

1 88
Download 88 pages 58.88 Kb
Page 58
Image 58

Operating Procedures

6.6Emergency Shutdown With EPO

This circuit has been designed to switch off the UPS in emergency conditions (i.e., fire, flood, etc.). The system will turn off the rectifier, inverter and stop powering the load immediately (including the inverter and bypass), and the battery stops charging or discharging.

If the input utility is present, the UPS’s controls will remain active; however, the output will be turned off. To remove all power from the UPS, the external feeder breaker should be opened.

6.7Auto 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.

6.8Reset 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:

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.

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.

After the EPO button is pressed, if the input utility is removed, the UPS will shut down completely. When input utility is returned, if the rotary switch (SW1) is in either Bypass or in Normal position, the UPS will start up on Bypass. There will be power at the output terminals of the UPS.

! WARNING

If the rotary switch is in the Maint. position and input utility is present, there will be power at the output terminals of the UPS.

50

Page 58
Image 58
Liebert NX UPS System user manual Emergency Shutdown With EPO, Auto Restart