6.2.2Bypass Mode

The UPS automatically switches to Bypass mode if it detects an overload, load fault, or internal failure. The bypass source supplies the commercial AC power to the load directly.

Figure 6---3 shows the path of electrical power through the UPS system when operating in Bypass mode.

CAUTION:

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

BYPASS MODE

 

 

STATIC

MAINTENANCE

K5

SWITCH

BYPASS SWITCH

 

 

 

RECTIFIER

BOOST

INVERTER

CONVERTER

CB1 K1

K3

 

MAINTENANCE

BYPASS SWITCH

CHARGER

K2

Main Power Flow

Breakers Contactors

 

Closed

CB2

 

Open

 

BATTERY

Trickle Current

Energized

De--Energized

Figure 6 ---3. Path of Current Through the UPS in Bypass Mode

In Bypass mode, the output of the system is provided with three phase AC power directly from the system input. While in this mode, the output of the system is not protected from voltage or frequency fluctuations or power outages from the source. Some power line filtering and spike protection is provided to the load but no active power conditioning or battery support is available to the output of the system in the Bypass mode of operation.

The internal bypass is comprised of a solid state silicon controlled rectifier (SCR) static switch (SSW), and a back feed protection contactor (K5). The static switch is rated as a continuous duty device that is used anytime the boost converter and inverter is unable to support the applied load. The static switch is wired in series with the back feed protection contactor and together they are wired in parallel with

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Powerware 9330 (10 kVA--40 kVA) Installation and Operation

 

164201300 REV. G 061502

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Powerware 9330 operation manual Bypass Mode