PARALLEL OPERATION
Liebert Trinergy™ Cube
User Manual - 10H52243UM60 - rev. 6 - 12/2020
Page 19
5. PARALLEL OPERATION
Up to eight units can be connected in parallel to increase power capacity and thus provide more secure
power to the load (redundancy).
The modules in parallel exchange information via a 25-wire shielded cable.
The total load current is shared between the modules.
For optimum performance of the parallel system and proper current sharing, especially in bypass mode,
make sure that the series impedance of the modules in parallel is the same.
The cross section and length of the power cables used to connect the inputs of each UPS module must
be the same. This also applies to the output cables and the battery cables, if the modules are connected
to the same DC source. For longer distances, cable lengths may not vary by more than 10%.
5.1. Commissioning
Commissioning of multiple-block systems must be carried out by appropriately trained technicians.
5.2. Communication between UPS blocks
UPS units exchange information through the connector cable (25-pin connector). The communication
cables are shielded and must be run separately and distanced from the power cables. The total length
of these cables should not exceed 40m.
5.3. Parallel switching procedures
Procedures refer to para. 2.3 on page 10.
5.4. Procedure 1: UPS TURN-ON PROCEDURE
Starting with each UPS completely de-energized, this procedure explains how to switch on a UPS and
set it to the normal operation mode.
On each UPS, perform the following procedure:
STEP
ACTION
STATUS
1
Energize all the UPS of the system by closing the upstream
breakers (mains and bypass)
2
Switch QS1 on Box to ON position (all UPS)
Only in case of BOX in
version FULL
3
Switch QS1-n on each Core to ON position (all UPS)
4
Wait for rectifier on each Core to ON position (all UPS)
On the TS-LCD the rectifier
icon is green and the VDC is
> 700V
5
Switch QS44 to ON position (all UPS)
6
Switch QS2 to ON position (all UPS)
Fans on the BOX ON
7
Switch QS4_n on each Core to ON position (all UPS)
Fans on each Core ON
8
Switch QS9_n on each Core to ON and close the external
battery disconnector (all UPS)
9
Switch QS4 on Box to ON position (all UPS)
Only in case of BOX in
version FULL
Once the previous steps have been performed for all UPS in the system proceed
with the further steps
10
Turn inverter ON by pressing the ON button on the
TS-LCD of each UPS
System in normal mode
