Emerson Series 600 User Manual

The Liebert FS must be operated with a backup AC power supply to protect the unit’s mechanical 

bearings if:

• the external DC supply is lost and
• the Liebert FS has developed a fault

If these two events occur simultaneously, the backup power supply will power the magnetic levitation 

hardware to prevent the rotating group from running on the mechanical touchdown bearings.
This section details the function of the backup power supply and how it should be attached to the 

Liebert FS. This is supplementary information—refer to appropriate sections of the user manual for 

details on installation and operation.

Note: Connection to a 480VAC supply requires a 480 to 110 transformer, available from Liebert as an 

option.

110 to 230VAC, 400VA

Frequency: 50 to 60Hz

In parallel 

with batteries

Attaching the backup AC power supply to the output of the UPS.

Without batteries

Feeding the backup AC supply from a separate, protected supply. 

This may be the output of another UPS or a supply from a separate 

feeder circuit.