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User Manual 10H52267UM60 - Rev. 1 - 09/2018
EXS
Maintenance bypass
The UPS is equipped with a second bypass circuit, known as the maintenance bypass, which provides a safe working
environment for the engineers to carry out regular maintenance or repair the UPS system, while providing unregulated
mains supply to the loads. The maintenance bypass can be activated manually selected by closing the maintenance
bypass switch, and disconnected by setting the switch to OFF.
Warning
If the UPS system consists of two or more UPS modules, and the load exceeds the capacity of the individual UPS modules, do not
use the internal maintenance bypass switch.
1.2.4
UPS Power Supply Switch Configuration
The UPS is equipped with four switches: main input switch Q1, bypass input switch Q2, maintenance bypass switch Q3,
and output switch Q5.
Figure 1-2 illustrates the block diagram of the UPS module. The UPS is available in separate bypass (where the bypass
is supplied by a separate mains input source) or common input configuration. If the system is installed in the common
input configuration, copper shorting bars are connected between the UPS rectifier and bypass input lines so that the
bypass input switch (Q2) and main input switch (Q1) are be linked together. To install the system in separate bypass
configuration, simply remove the common input configuration input shorting bars.
During the normal UPS operation, all switches should be closed, with the exception of the maintenance bypass switch
Q3.
Bypass input
Mains input
Neutral line input
Battery
BCB
Rectifier
Inverter
Charger
UPS
Maintenance bypass
switch Q3
Bypass input switch Q2
Rectifier input
switch Q1
Bypass automatic switch
Inverter Output
switch Q5
UPS output
Shorting copper bar
of common input
configuration
DC bus
switch
Figure 1-2
UPS power supply switch configuration
Note: The main input and bypass input must use the same neutral line.
1.2.5
Battery Circuit Breaker (BCB)
The external battery shall be connected to the UPS via the BCB. The BCB box is an option that must be installed close
to the battery. The BCB is closed manually and is fitted with a shunt tripping coil. When the system is faulty and it is
necessary to disconnect the BCB, the UPS control circuit will send a signal to the shunt tripping coil so as to trip the
BCB. It also features a magnetic trip function for overload and short circuit protection.
1.3
Parallel System
Up to four UPS modules may be parallel-connected to form a parallel system and increase the system capacity and
reliability. The load is shared equally between the UPS modules connected in parallel.
