Emerson NX manual Load on Bypass, DC Bus, Load on bypass, UPS available

Operation

2.4.1Load on Bypass

In this operating mode, the connected loads are supplied from line power via the Static Bypass Switch. The Static Bypass Switch is used to provide power to the loads. If an overload or short-circuit on UPS output occurs, the Static Bypass Switch is automatically activated to provide uninterrupted power to the loads. The Bypass operating condition is displayed. From this operating mode, the UPS automatically reverts to on-line operation after the fault is corrected. Bypass operation can also be specifically selected from the control panel using the push button.

Load on Bypass is shown in Figure 13. The UPS system could be in this mode of operation during either initial startup or UPS system shutdown or isolation for maintenance.

NOTICE

Risk of unexpected power loss. Can cause equipment damage.

When the critical load is being supplied power from the bypass line, the load is vulnerable to utility failure and fluctuations.

Figure 13 Load on bypass

Module Bypass

AC Input

BFB

Module Rectifier

AC Input

DC

Bus

To DC Supply

UPS Module

UPS Output	Critical
	Load

Figure 14 Load on bypass, UPS available

Module Bypass
AC Input
	BFB
Module Rectifier	DC
AC Input
	Bus

UPS Module

UPS Output Critical

Load

To DC Supply

Figure 15 Load on UPS, bypass available

Module Bypass
AC Input
	BFB
Module Rectifier	DC
AC Input
	Bus

UPS Module

UPS Output Critical

Load

To DC Supply

15 Liebert®NX™