Powerware 650825 kVA User Manual

UNDERSTANDING UPS OPERATION

EATON Powerware

®

 9395 UPS (650–825 kVA) Installation and Operation Manual  

S

  164201725 Rev 2 www.powerware.com

6−4

6.2.3

Bypass Mode

NOTE  

Bypass mode is  not available on an UPS configured as an IOM.

The UPS automatically switches to Bypass mode if it detects an overload, load fault,
or internal failure. The UPS can also be transfered from Normal mode to Bypass mode
manually. The bypass source supplies the commercial AC power to the load directly.
Figure 6-3 shows the path of electrical power through the UPS system when
operating in Bypass mode.

Static

Switch

K5

Rectifier

Inverter

K1

K3

Battery

Converter

Battery

Battery
Breaker

Main Power Flow

Trickle Current

Energized

De−Energized

Closed

Open

Breakers

Contactors

K2

Bypass Input

Rectifier
Input

Output

Bypass

Breaker

(CB4)

Input

Breaker

(CB1

NOTE  On an UPS configured as an IOM, the bypass input, static switch, bypass breaker (CB4), and K5 are not present.

Figure 6-3. Path of Current Through the UPS in Bypass Mode

C

 

A

 

U

 

T

 

I

 

O

 

N

The critical load is not protected while the UPS is in Bypass mode.

In Bypass mode, the output of the system is provided with three−phase AC power
directly from the system input. While in this mode, the output of the system is not
protected from voltage or frequency fluctuations or power outages from the source.
Some power line filtering and spike protection is provided to the load but no active
power conditioning or battery support is available to the output of the system in the
Bypass mode of operation.