2: General Description
8
TS_619_00 PW9000DPA S2 User Manual 13/3/17
to three minutes, whereupon it begins flashing red. This allows the operator to gauge the remaining autonomy time and,
where necessary, shut down the load in an orderly manner (e.g. save data) before the battery is fully discharged. Various
options are available to automate the load shut down process and if an automated data protection application is installed it
usually begins its automatic shut down routine at this point.
The initial audible alarm can be cancelled but it will reappear when the battery voltage falls to its
LOW
BATTERY
alarm
threshold, whereupon the audible alarm sounds once again to warn the operator that the battery is nearing its end-of-
discharge.
Eventually, the
BATTERY
LED changes to solid red when the battery reaches its fully discharged voltage, and the UPS will
attempt to transfer the load to the bypass supply if the supply is present.
Load on bypass
In the ‘load on bypass’
mode the static switch
connects the load to the
unprotected static
bypass line.
This mode can be
selected manually (see
‘ECO Mode’ below) or
entered as the result of a
UPS fault (or overload)
condition which transfers
the load to bypass
because the inverter is
unable to support it.
Depending on the reason for entering the ‘load on bypass’ mode, the rectifier and charger sections might be turned off
entirely or remain operational and continue to provide battery charging (as shown above). Similarly, the inverter may have
been manually turned OFF or shutdown due to a fault, and the
INVERTER
LED on the module control panel may be either
OFF or solid RED.
Module OFF (Maintenance bypass)
When the UPS module
is turned OFF, all of its
internal power blocks
are effectively shut down
but the module input
power terminals remain
live unless the UPS
input/bypass mains are
externally isolated.
The maintenance
bypass switch (IA-1) can
be closed to maintain the
load supply, but in a
single UPS cabinet
installation this requires
the bypass mains supply
to remain live and
thereby prevents the bypass supply from being externally isolated.
Only one maintenance bypass switch is fitted per UPS cabinet and if the cabinet contains several modules (DPA-150,
DPA-250) the maintenance bypass switch (IA-1) bypass them all.
When operating a multi-cabinet system, the internal cabinet maintenance bypass switch (IA-1) should not be used, and an
external maintenance bypass installation that wraps-around the complete multi-cabinet system is required – usually
installed in a dedicated maintenance bypass cabinet, or wall-mounted as described in paragraph 3.4.2.
RECTIFIER
BATTERY
INVERTER
STATIC
SWITCH
BOOSTER /
CHARGER
INV. Output
Contactor
Bypass Mains
UPS MODULE
Static bypass line
UPS Input Mains
UPS Output
to critical load
Figure 2.6 Load on bypass
RECTIFIER
BATTERY
INVERTER
BOOSTER /
CHARGER
INV. Output
Contactor
Bypass Mains
UPS MODULE
Static bypass line
UPS Input Mains
UPS Output
to critical load
IA-1
Maintenance bypass line
STATIC
SWITCH
Figure 2.7 Module OFF (Load on maintenance bypass)