Powerware 9395 UPS and Plus 1 UPS 650825 kVA - Manual (Page 116)

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.