American Power Conversion PX user manual On-Battery Operating Mode, Bypass Operating Mode

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. SymmetraTM 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. SymmetraTM 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.

System Control
and Interface
Powerview User	Communication
Interface	Card and
	SmartSlotsTM

Bypass Operating Mode

When the SymmetraTM is in the bypass operating mode, the system is bypassed and utility power is delivered directly to the load. SymmetraTM 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 SymmetraTM 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 SymmetraTM 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.

System Control
and Interface
Powerview User	Communication
Interface	Card and
	SmartSlotsTM

	Communication
Power Processing
	Discharge
	Bypass
AC	Switch

Communication

Battery Source

AC

Communication

Power Processing

Charge

Communication

Battery Source

IN

OUT

	Bypass
AC	Switch	AC
IN		OUT

Fig I-5 On-Battery Operating Mode

Fig I-6 Bypass Operating Mode

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