GE LP 33U Series Operating Manual page 15

Manual bypass operation
The manual bypass circuit consisting of Q1 and
Q2 manual switches permits the transfer of the
load directly to the utility without interruption,
leaving the UPS galvanically separated from the
output load.
This type of operation is normally used when the
UPS system must be completely turned off for
maintenance or reparation.
Utility failure operation
In the event of a utility power failure, the
rectifier and the battery-charger turn OFF,
while the inverter continues to supply the load
without interruption using the energy stored in
the battery.
During the battery discharge, the LCD screen
displays the remaining autonomy, based on the
battery capacity and the applied load.
In the event of an extended utility failure, before the battery is fully discharged, the alarm "stop
operation" warns the user that the UPS will start the shutdown procedures when the indicated time
expired (normally 3 minutes).
In case of parallel system
With parallel system for power capacity:
• With the bypass utility power available as the warning "battery low" occurs on one unit, after
timeout (selectable) the load is transferred to utility.
• With missing bypass utility power as the warning occurs on one unit, the system starts the
timeout (selectable) of "Stop operation" and then the output load shuts down.
With redundant parallel system:
• As the warning battery low occurs on one unit unnecessary to support the present load, after
timeout (selectable) this unit shuts down and the load is shared between the other units.
As the warning occurs on one unit necessary to support the present load, the system starts the
timeout (selectable) of "stop operation" and then the output load shuts down.
Modifications reserved
OPM_LPS_3UO_50K_60K_1US_V010.doc
Fig. 4.2-5 Energy flow in manual bypass operation
Fig. 4.2-6 Energy flow during utility failure operation
Page 15/65
Operating Manual LP 33U Series 30 & 40 kVA