Bypass Mode; Figure 6-2. Path Of Current Through The Ups In Normal Mode - Eaton Powerware 9395 UPS 10001100 kVA Installation And Operation Manual

Bypass Input
Input
Breaker
Rectifier
(CB1
Input
K1 K1
Breakers Breakers Contactors Contactors
6.2.3
EATON Powerware
®
Bypass
Breaker
(CB4)
Static Static
Switch Switch
Rectifier Rectifier
Battery
Converter
Closed Closed
Open Open
Battery

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

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.

Bypass Mode

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.
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.
9395 UPS (1000–1100 kVA) Installation and Operation Manual
K5
Inverter Inverter
K2
Battery Battery
Breaker Breaker
C A U T I O N
S 164201764 Rev 1 www.powerware.com
UNDERSTANDING UPS OPERATION
Output
K3 K3
Main Power Flow Main Power Flow
Trickle Current Trickle Current
Energized Energized
De−Energized De−Energized
6−3