Chapter 3 : Modular systems
UPS/NTA GB/ DELMX_EXPC1C3C6.B
page 22
9.4.2.System with two non redundant units or more than two parallel units
The transfer of the system to the maintenance bypass should be carried out as follows :
-
request a "load to mains" command in the menu " General UPS / UPS commands"
from any unit.
-
close switch Q5 of the external maintenance bypass.
-
Open switches Q3 of all the units.
9.4.3.Shutdown of the units
Successively shutdown the units as per the following procedure :
* uncouple the unit in the menu "unit / subset commands / unit uncoupling",
* stop the inverter in the menu "unit / subset commands / inverter shutdown",
* open battery protection Q20,
* stop the rectifier in the menu "unit / subset commands",
* open switch Q4
* open switch Q1
Note : at this point the load is supplied by the maintenance bypass (without protection)
and all the units are stopped.
CAUTION
Do not forget that even when the load is stopped the unit is live
:
- because of the mains voltage to the rectifier and the bypass.
- because of the residual voltage of the capacitors.
- because of the load voltage when the maintenance bypass Q5 is closed
and the bypass mains is present.
9.5.Operation of a unit
The unit can be operated through this menu in case of servicing operations on the unit.
9.5.1. Uncoupling a unit from the common busbar
CAUTION
Unit uncoupling can only be achieved if the system is
redundant, meaning that it can supply all the energy
required to the load with one unit disconnected.
The uncoupling of a unit is to be made from its control panel :
- uncouple the appropriate unit in the menu "unit / unit commands / unit uncoupling",
- open switch Q3 on the appropriate unit.
Note: At this point the unit can be autonomously operated.
