Figure 6-2. Path Of Current Through The Ups In Online Mode - Eaton Power Xpert 9395 Installation And Operation Manual

The inverter produces a three-phase AC output to a customer's load without the use of a transformer. The
inverter derives regulated DC from the rectifier and uses IGBT devices and pulse-width modulation (PWM) to
produce a regulated and filtered AC output. The AC output of the inverter is delivered to the system output
through the output contactor K3.
Bypass Input
Input
Breaker
Rectifier
(CB1
Input
K1 K1
Breakers Breakers Contactors Contactors
NOTE On a UPS configured as an IOM, the bypass input, static switch, bypass breaker (CB4), and K5 are not present.
NOTE On a UPS configured with a Continuous Static Switch (CSS), bypass breaker (CB4) is not present.

Figure 6-2. Path of Current Through the UPS in Online Mode

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.
NOTE
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.
® ®
Eaton Power Xpert 9395P-300 (300kVA, 300kW) UPS Installation and Operation Manual
Static Static
Switch Switch
R R c e c e f i t f i t r e i r e i
Battery
Converter
Closed Closed
Open Open
Battery
Bypass mode is not available on a UPS configured as an IOM.
K5
I I v n v n r e r e r e t r e t
K2
Battery
Breaker
P-164000563—Rev 04 www.eaton.com/powerquality
Understanding UPS Operation
Output
K3 K3
Main Power Flow Main Power Flow
Trickle Current Trickle Current
Energized Energized
De-Energized De-Energized
6-3