LEGRAND VR61-18 Manuel De L'utilisateur page 17

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
UPS user manual
Manuel de l'utilisateur de l'ASI
Utilizzo dell'UPS
OMP06145 REV. D 17