Eaton
Power Xpert 9395P UPS (300 kVA, 300 kW) Installation and Operation Manual
S
P-164000563 Rev 1
www.eaton.com/powerquality
6-1
Chapter 6
Understanding UPS Operation
6.1
UPS System Overview
The Eaton 9395P UPS is a continuous-duty, solid‐state, transformerless (at 480 Vac),
three-phase, true online system that provides conditioned and uninterruptible AC
power to the UPS system's output and critical load.
The basic system consists of a rectifier, battery converter, inverter,
monitoring/operation control panel, integrated communication server, and digital
signal processor (DSP) logic. Figure 6‐1 shows the main elements of the UPS system.
If utility power is interrupted or falls outside the parameters specified in Chapter 10,
“Product Specifications,” the UPS uses a backup battery supply to maintain power to
the critical load for a specified period of time or until the utility power returns. For
extended power outages, the UPS system allows you to either transfer to an
alternative power system (such as a generator) or shut down your critical load in an
orderly manner.
Output
Contactor
K3
Battery
Battery
Breaker
Battery
Converter
Input
Contactor
K1
AC Input to
Rectifier/
Charger
AC Input to
Bypass
Backfeed
Protection
Contactor
K5
Power Module
Inverter
Rectifier
Digital
Metering
Static
Switch
AC Output
to Critical
Load
UPS Cabinet
Battery
Contactor
K2
Battery System
Input
Breaker
CB1
(optional)
NOTE
On a UPS configured as an Input Output Module (IOM), the bypass input, static switch, and backfeed protection
contactor (K5) are not present.
Figure 6‐1. Main Elements of the UPS System
The emergency bypass consists of a continuous static switch, and a backfeed
protection contactor K5. The bypass breaker (if installed) is located in parallel with the
static switch. The backfeed protection contactor is located in series with the static
switch. The static switch is armed and ready during normal operation.
Figure
