LEGRAND BSK93, Operating Manual

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UPS user manual
Manuel de l’utilisateur de l’ASI
Utilizzo dell’UPS
16 OMW07104 REV. A
When the Green Conversion algorithm is active the rectifier operates at reduced DC voltage and supplies
the inverter alone, since the battery is disconnected from the DC bus. The battery charge is controlled by
a specific algorithm. In case no mains outage events have occurred, and so no battery discharges have
occurred too, the control logic provides to start a charging cycle once every 25 days. The battery-charger
restores the capacity lost due to the self-discharge and remains in floating charge for additional 12 hours.
As this time has elapsed the battery static switch is opened and the battery is disconnected from the DC
bus.
In case a discharge event occurs, the control logic provides to calculate the capacity which has been lost
during the discharge; as the mains is restored a charging cycle is started, which is extended for an
additional time that depends on the percentage of lost capacity, referred to the rated value.

Lost capacity < 10%

Additional charge for 12 hours

Lost capacity between 10% and 20%

Additional charge for 48 hours

Lost capacity > 20%

Additional charge for 96 hours
Such values complies with the recommendations of the main battery manufacturers.
Set the right battery capacity
The UPS front panel allows the setting of the battery parameters, including the rated
capacity. Considering the importance that such value assumes for the correct execution of
the charge control algorithm, it is highly recommended to verify the correctness of the
programmed value.
3.3.3 Bypass operation
The load can be switched to bypass either automatically or manually. The manual changeover is due to
the BYPASS SWITCH which forces the load to bypass. In case of failure of the bypass line, the load is
switched back to inverter without interruption.
Picture 4 – Load supplied by bypass
3.3.4 Battery operation
In case of power failure or rectifier fault, the battery feeds the inverter without interruption. The battery
voltage drops based on the amplitude of the discharging current. The voltage drop has no effect on the
output voltage, which is kept constant by changing the PWM modulation. An alarm is activated when the
battery is near the minimum discharge value.
In case the supply is restored before the battery is completely discharged, the system will be switched back
to normal operation automatically. In the opposite case, the inverter shuts down and the load is switched