APC PX - On-Battery & Bypass Modes

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On-Battery Operating Mode

When in the on-battery mode, the Power Array draws DC

power from the battery source, converts it to conditioned AC

power and delivers it to the load equipment. Symmetra

typically enters this mode in the event of a mains (utility) power

failure. It will also operate in the on-battery mode during a

user initiated battery self test.

On-battery operation is limited in duration and is dependent

on the number of battery modules, their state of charge, and

the size of the load. Symmetra

will remain in the on-battery

state until either the incoming utility power is restored or the

batteries are depleted. See figure I-5 for a diagram of power

flow when the system is in the on-battery mode.

Fig I-5 On-Battery Operating Mode

Bypass Operating Mode

When the Symmetra

is in the bypass operating mode, the

system is bypassed and utility power is delivered directly to the

load. Symmetra

is equipped with an automatic bypass func-

tion to allow the system to automatically go into bypass mode,

and a manual maintenance bypass switch to allow a user to

manually bypass the system. Either can be used to place the

Power Array into bypass operating mode.

The Symmetra

will automatically transfer to the bypass

operating mode when AC mains power is present, but the

load cannot be powered by the inverter. Events which may

cause this include overloads and failed non-redundant power

modules. The Symmetra

will automatically return to the

on-line mode when the triggering event clears. Figure I-6 illus-

trates power flow when the system is in the bypass mode.

Fig I-6 Bypass Operating Mode

System Control

and Interface

Communication

Card and

SmartSlots

Powerview User

Interface

Communication Communication

Power Processing Battery Source

Discharge

Bypass

Switch

OUT