Comet 40-150kVA

3.5Operating Procedures

3.5.1Normal Operation

The AC input power is present.

The green "Load Protected" LED is on. The GUI display indicates the operating status of the UPS.

The power drawn by the load is supplied by AC input power via the Rectifier and Inverter modules. The Battery Charger float charges or recharges the battery.

The GUI display indicates “Load Protected”.

3.5.2Operation on Battery Power

When AC input power fails or is out of tolerance, the Rectifier shuts down and the battery supplies the power required by the Inverter to supply the load. The battery discharges.

The green "Load Protected" LED is on. The GUI display indicates the operating status of the UPS.

The user is warned of operation on battery power by the buzzer and by the yellow "Battery Status" LED. This information is also available via the standard UPS MANAGER DB15 connector.

3.5.3Battery Duration

During an AC input power failure, the duration of Inverter operation on battery power depends on:

The rated capacity of the battery.

The power drawn by the load.

The battery temperature.

The charge level of the battery.

The age of the battery.

The real backup time, which depends on the actual load, may be greater if the Inverter operates at less than full rated load. It is possible, during operation on battery power, to increase the battery backup time by reducing the power drawn by the load (shedding of non-priority load).

A low battery shutdown warning signal is available via the standard UPS MANAGER DB15 connector for remote indications. It warns the user of upcoming battery shutdown at a user-determined level of remaining power.

On the UPS itself, the buzzer beeps louder and more rapidly, and the yellow "Battery Status" LED flashes rapidly.

The end of battery power occurs when the battery reaches shutdown level. At this point, the Inverter shuts down and the UPS goes into "Stand-By" mode. Load is no longer supported. If the input AC power does not return to within tolerance within approximately 2 hours, the unit will shutdown.

Once input AC power returns, the batteries begin their charging cycle. It takes approximately 10 hours of online operation to restore 10 minutes of backup time.

3.5.3.1 Return to AC Power

When the AC input power failure ends or power returns to within tolerances:

If the end of battery backup power was not reached, the Comet returns to normal operating mode.

If the end of battery backup power was reached and unit is in "Standby" mode, the Rectifier and the Inverter automatically start up (the inverter must be manually started if the system is in manual startup mode).

If the end of "Stand-By" mode was reached, follow the Startup procedure.

3 —6

Operation

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MGE UPS Systems 40-150kVA user manual Operating Procedures, Normal Operation, Operation on Battery Power, Battery Duration