Powerware Powerware 9390 manual Parallel Redundant Configuration

UNDERSTANDING OPERATION

3.1.2Maintenance Bypass Mode with UPS Sidecar

An MBP is used to safely supply utility power to the critical load during periods of UPS maintenance or repairs. The bypass source supplies the commercial AC power to the load directly.

When the MBP is closed, the load is wrapped around the UPS while power is still supplied to the load by the UPS through the MIS. The MIS is then opened, isolating the UPS from the Bypass power source. The UPS can be safely shut down and power removed from the UPS without interrupting power to the critical load. If the optional BIB and RIB are installed, the BIB and RIB are opened to remove power from the UPS. Otherwise, external upstream breakers are used to remove power. The UPS now can be serviced or replaced safely.

The critical load is not protected while the UPS is in Maintenance Bypass mode.

Figure 3-2 shows the path of electrical power through the UPS Sidecar when operating in Maintenance Bypass mode.

TO UPS RECTIFIER INPUT

TO UPS BYPASS INPUT

AC INPUT

TO UPS

RIB

(OPTIONAL)

BIB

(OPTIONAL)

AC INPUT

TO BYPASS

FROM UPS OUTPUT

MIS MBP

UPS SIDECAR

OUTPUT TO CRITICAL LOAD

MAIN POWER FLOW IN UPS MODE

MAIN POWER FLOW IN MAINTENANCE BYPASS MODE

Figure 3-2. Path of Current Through the UPS Sidecar in Maintenance Bypass Mode

3.2Parallel Redundant Configuration

Refer to the applicable Powerware 9390 installation and operation manual, listed in paragraph 1.5, for parallel theory of operation.

3-2 EATON Powerware® 9390 UPS Sidecar Installation and Operation Manual S 164201586 Rev E www.powerware.com