Eaton Power Xpert 9395C UPS Installation and Operation Manual 164000821—Rev 06
89
Figure 54. Path of Current Through the UPS in Online Mode
Static
Switch
r
e
tr
e
v
n
I
r
e
if
it
c
e
R
Battery
Converter
Battery
Battery
Breaker
Main Power Flow
Trickle Current
Energized
De-Energized
Static
Switch
r
e
tr
e
v
n
I
r
e
if
it
c
e
R
Main Power Flow
Trickle Current
Energized
De-Energized
Bypass Input
Rectifier
Input
Output
K1
Closed
Open
Breakers
Contactors
If the utility AC power is interrupted or is out of specification, the UPS automatically switches to Battery mode
to support the critical load without interruption. When utility power returns, the UPS returns to Normal mode.
If the UPS becomes overloaded or unavailable, the UPS switches to Bypass mode. The UPS automatically
returns to Normal mode when the overload condition is cleared and system operation is restored within
specified limits.
If the UPS suffers an internal failure, it switches automatically to Bypass mode and remains in that mode until
the failure is corrected and the UPS is back in service.
66..22..33
EEnneerrggyy S
Saavveerr S
Syysstteem
m ((EES
SS
S)) M
Mooddee
When the UPS is operating in ESS mode, commercial AC power is supplied directly to the critical load through
the continuous static switch. Power line filtering and spike protection for the load are provided by the input and
output filter networks, and the UPS actively monitors the critical bus for power disturbances. When in this
mode, the input contactor is closed and the link is maintained through the diode bridge.
If commercial power voltage or frequency disturbances are detected, the system forward transfers to Battery
mode for minor disturbances and then to double-conversion mode for more severe disturbances. During a
complete power outage, the transfer takes place within 2 ms to ensure loads being fed by the system output
are not interrupted. All forward transfers transfer to Battery mode before returning to double-conversion mode.
In High Alert mode the unit transfers from ESS mode to double-conversion mode or if in double-conversion
mode remains in double-conversion mode for a default time period of one hour (customer configurable). At the
completion of the time period, the unit defaults back to ESS mode. If the High Alert command is received
during the time period, the timer will be restarted.
ESS mode is a normal operating mode, and not an alarm condition. While the UPS is in this mode, the Online
light on the front display will illuminate.
Summary of Contents for Power Xpert 9395C
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