Emerson NX Manual Operations-All Systems, Remote Emergency Power Off, UPS Module, Critical Load

Operation

2.4.4Remote Emergency Power Off

The Remote Emergency Power Off control is a user-provided switch located remotely from the UPS system. It usually is installed in the same room as the critical load equipment. This mode can also be initiated by an automatic contact closure in the same external circuit as the manually operated switch.

When the Remote Emergency Power Off switch is operated, the UPS will shut down and open bypass circuit breakers. All power through the UPS is removed from the load. Typically, the REPO circuit also opens the circuit breakers that provide power to the bypass lines and the UPS controls. Refer to 2.5.8 - Shut Down-Single Module UPS System.

Figure 18 Remote Emergency Power Off

Module Bypass

AC Input

BFB

Module Rectifier

AC Input

	UPS Module
DC	UPS Output
Bus

Critical

Load

To DC Supply

2.5Manual Operations—All Systems

The Liebert NX UPS is designed to function while unattended by an operator. The system control logic automatically handles many important functions, as explained in 2.16 - Automatic Operations. Other procedures must be performed manually.

Manual procedures available to the operator include startup, load transfers and shutdowns. These procedures are performed by using the touchscreen and some manually operated circuit breakers and switches.

This section lists typical step-by-step instructions.

•Startup—Including initial startup, recovering from input power failure, recovering from DC source shutdown and recovering from shutdowns for emergencies or maintenance.

•Load Transfers-Including transfers from UPS to bypass and retransfers from bypass to the UPS system.

•Maintenance Bypass Load Transfers—Including transfers from internal bypass to maintenance bypass and transfers from maintenance bypass to internal bypass.

•Shutdowns—Including module shutdowns for maintenance and emergency shutdowns.

NOTE

The following procedure assumes that the UPS installation inspection and initial startup have been performed by Emerson Network Power® Liebert Services. An Emerson-authorized representative must perform the initial system startup to ensure proper system operation.

17 Liebert®NX™