Emerson SERIES 600T User Manual

To charge the Liebert FS, the Liebert FS will draw power from the UPS DC bus to accelerate the fly-

wheel (as long as the UPS DC bus voltage is higher than Vcharge). In this mode, the Liebert FS State 

of Charge (SOC) will progressively increase from 0% to 100%.

The Liebert FS will be in CHARGE mode as long as:

• Liebert FS’s SOC is between 0% and 100% and
• UPS DC Bus Voltage 

≥ 

Vcharge.

When the SOC reaches 100%, the unit will automatically transition into the READY mode. This is the 

mode in which the Liebert FS will spend most of its operating time. In this mode, the Liebert FS 

maintains its State Of Charge greater than 99.5%. The Liebert FS’s SOC will be allowed to drift down 

to SOC = 99.5%, at which point it will transition back into CHARGE mode and charge back up to 

READY mode and SOC = 100%. During normal operation, the Liebert FS will continue to automati-

cally transition between the READY and CHARGE modes to maintain a SOC between 99.5 and 100% 

until either a DISCHARGE or SHUTDOWN is initiated.

The Liebert FS will be in READY mode as long as:

• Liebert FS’s SOC is between 99.5% and 100% and
• UPS DC Bus Voltage 

≥ 

Vcharge.

NOTE
While in CHARGE mode, the Liebert FS will be capable of supporting the UPS DC bus.

NOTE
While in READY mode—just as in CHARGE mode—the Liebert FS will be capable of 

≥ Vcharge

≥ Vcharge