Tescom DS300B Series, User Manual

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The AC inputs of all UPSs in the parallel system are connected to the same mains, and all the AC
outputs are connected to each other. Each UPS has its own battery group. The critical load is connected to
the common output of the parallel system. There are also some signal cable connections between the UPS
units necessary for parallel operation, and will be described later.
4.2
Parallel Operation Mode settings of DS300B Series UPSs
NOTE: Parallel operation hardware (parallel communication board) are not installed in a
standard DS300B series UPS, but parallel operation option is available and can easily be
added to all UPSs.
N+1 REDUNDANT parallel operation
For parallel operation some parameters must be given by the service personnel these are:
1- Select Parallel mode must be selected from ADJUST MENU (ADJUST MENU/INV FACTORY
OPTIONS/OPERATING MODE:)
2- A unique UPS network no must be given from ADJUST MENU(ADJUST MENU/INV FACTORY
OPTIONS/UPS NO:) (each UPS must be assigned a unique UPS number)
3- Minimum UPS quantity requirement must be given from ADJUST MENU (ADJUST MENU/INV
FACTORY OPTIONS/N+1 MINIMUM:) (N number in the system)
Shown parameters can not be adjust by the user, these parameters are located on ADJUST MENU also
adjust menu is password protected only authorized service personnel can access this menu.
PARALLEL mode
This mode is used for operation of at least two (1+1 configuration) UPS units connected in parallel for
increased reliability. If this mode is selected, the load is shared equally by each UPS available in the
parallel system (N+1 numbers of UPS units), during normal operation.
In case of a failure of any one of the UPS units, the faulty UPS is isolated from the parallel system and
the critical load is supplied by the remaining N number of UPSs. If any one of those UPS units fails too,
then the critical load is transferred to bypass supply via the static bypass switches of the parallel connected
UPSs. If the faulty UPS returns to normal operation, it joins the parallel system again and starts sharing the
load.
In parallel mode, the total VA rating of the parallel system is equal to the VA rating of a single UPS
multiplied by N.
In parallel mode, you will see ‘’PARALLEL MODE /MS’’(master UPS) or ‘’PARALLEL MODE /sl’’ (slave
UPS) message on the LCD panels of all the all UPS units.
More detailed diagrams for two (or more) DS300B series UPSs connected in parallel are given in Figures
4.2 and 4.3
Communication between parallel UPSs are provided over one pair cable (PCC06). The length of the cable
is limited up to six meters.
A link cable is used for connecting the first UPS to the last UPS ,this cable is redundant for normal
communication cables.
If communication is lost on SLAVE UPS the UPS will shutdown but the MASTER UPS will go on running if
the communication is provided at SLAVE UPS it will start automatically again.