Powerware 650825 kVA operation manual Path of Current Through the UPS in Bypass Mode

UNDERSTANDING UPS OPERATION

6.2.3Bypass 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 6-3shows the path of electrical power through the UPS system when operating in Bypass mode.

Bypass Input

Bypass

Breaker

(CB4)

Static

Rectifier Input

Input

Breaker

(CB1

Rectifier

K1

Switch

K5

Inverter

K3

Output

Breakers Contactors

Closed

Open

Battery

Converter

K2

Battery

Breaker

Battery

Main Power Flow

Trickle Current

Energized

De−Energized

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.

6−4 EATON Powerware® 9395 UPS (650–825 kVA) Installation and Operation Manual S 164201725 Rev 2 www.powerware.com