Powerware 100160 kVA manual Normal Mode Parallel

Understanding UPS Operation

7.3.2 Normal Mode – Parallel

In Normal mode, utility AC power is supplied to the UPMs. Each UPM then conditions the incoming AC power and provides clean, regulated AC power to either a module tie cabinet or distribution panel for parallel systems up to four modules. The applied load is equally shared among the available UPMs in the system.

Figure 7-5 shows the path of electrical power through the parallel system when operating in Normal mode.

Bypass Input UPM Input

UPM 1

Battery

UPM 2

Battery

UPM 3

Battery

UPM 4

Battery

	Breakers
Main Power Flow	Closed
	Open

Module Tie Cabinet

UPM 1 Output

UPM 2 Output

UPM 3 Output

UPM 4 Output

Output to

Critical

Load

Figure 7-5. Path of Current through the UPMs in Normal Mode – Parallel

If the utility AC power is interrupted or is out of specification, the UPMs automatically switch to Battery mode to support the critical load without interruption. When utility power returns, the UPMs return to Normal mode.

If the UPMs become overloaded or unavailable, the parallel system switches to Bypass mode. The parallel system automatically returns to Normal mode when the overload condition is cleared and system operation is restored within specified limits.

EATON Powerware® 9390 UPS (100–160 kVA) Installation and Operation Manual S 164201604 Rev B powerware.com 7-11