Powerware 650825 kVA operation manual Bypass Mode Distributed Bypass

UNDERSTANDING UPS OPERATION

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

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

6.4.3Bypass Mode – Distributed Bypass

In Bypass mode, the output of the system is provided with three−phase AC power directly from the bypass input. While in this mode, the output of the system is not protected from fluctuations, spikes, or power outages from the source. No battery support is available to the output of the system in the Bypass mode of operation.

The distributed bypass system automatically switches to Bypass mode if it detects a UPS system overload or load fault.

If one UPS becomes unavailable, the distributed bypass system dynamically updates the redundancy calculation to determine if the remaining UPSs can support the load. If the load can be supported, the system does not switch to bypass.

Figure 6-19shows the path of electrical power through the parallel system when operating in Bypass mode.

Bypass Input	UPS Input
	UPS 1
Battery
	UPS 2
Battery
	UPS 3
Battery
	UPS 4
Battery

Breakers

Closed

Main Power Flow

Open

Tie Cabinet

UPS 1 Output

UPS 2 Output

UPS 3 Output

UPS 4 Output

Output to

Critical Load

Figure 6-19. Path of Current through the UPSs in Bypass Mode – Distributed Bypass

EATON Powerware® 9395 UPS (650–825 kVA) Installation and Operation Manual S 164201725 Rev 2 www.powerware.com 6−23