46 Chapter 5 Operating Instructions
6.4 Procedure For Switching The UPS Into A Maintenance Bypass From
Normal Mode
This procedure can transfer the load from the UPS inverter output to the maintenance bypass supply, but the
precondition is that the UPS is in normal mode before the transfer.
Caution
Before making this operation, read messages on display to be sure that bypass supply is regular and the inverter is synchronous
with it, so as not to risk a short interruption in powering the load.
1. Press the INVERTER OFF switch on the right side of the operator control panel for longer than two seconds (if
system is a interrupt transfer, there is a prompt to alarm and you must confirm the interrupt transfer). The UPS Mimic
indicator Inverter ON will extinguish and also the Status Indicator (6) will turn amber and will be accompanied by an
audible alarm. The load transfers to static bypass, and the inverter shuts down.
Note
Pressing the Alarm Silence ON/OFF button cancels the audible alarm but leaves the warning message displayed until the alarm
condition is rectified.
2. Open the UPS door, close the maintenance bypass switch on the right bottom of the unit from OFF to ON position.
The load power supply is provided by the manual maintenance bypass.
Warning
If you need to maintain the module, wait for 10 minutes to let the DC bus capacitor fully discharge before removing corresponding
module.
When the maintenance bypass switch is on position of ON, some part of the UPS circuit still has hazardous voltage. Therefore,
only qualified person can maintain the UPS.
Caution
When the UPS is in maintenance bypass mode, the load is not protected against abnormal mains supply.
6.5 Procedure For Completely Powering Down A UPS
If you need to power down the UPS completely, follow the procedures in section 6.3 to transfer the UPS from normal
mode to maintenance bypass mode.
If you need to isolate the UPS from the AC power supply, you should open the external input power supply isolation
first (if the rectifier and bypass use different power supply, you need to open these two input isolation respectively).
Warning
Shut down the maintenance power supply to avoid human injury.
6.6 EPO Procedure
The EPO button is designed to switch off the UPS in emergency conditions (e.g., fire, flood, etc.).To achieve this, just
press the EPO button, and 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 control circuit will remain active; however, the output will be turned off. To
completely isolate the UPS, you need to open the external mains input supply to the UPS rack.
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