Emerson 250-400kVA Manuel D’Utilisation

The OK to Transfer status message will be displayed when the bypass line and UPS output power are 

both available, their voltage, frequency and phase synchronization are matched within specifications, 

and the Static Switch Disconnects are closed (ON). An alarm message may be displayed to indicate 

Load On Bypass (Figure 24). If no alarm is displayed, the operating status is Load On UPS 

(Figure 25).
When the OK to Transfer message is displayed, the load can be manually transferred from the UPS to 

bypass or the load can be manually retransferred from the bypass to the UPS.
To perform a manual transfer, Use the Load Transfer Procedures screen. Refer to 2.4.2 - Load 

Transfer Procedures.
The UPS control logic will initiate an automatic transfer to bypass if an overload condition exceeds 

the system current versus time window or if a UPS fault is detected. The control logic may initiate an 

automatic retransfer to the UPS system when the system is recovering from overloads lasting less 

than five minutes. Refer to 2.6 - Automatic Operations.

Bypass

Input

Battery 

System

DC Bus

Module 

Output

BFB

CB2

CB1

MBD

Bypass

Input

Battery 

System

DC Bus

Module 

Output

BFB

CB2

CB1

MBD