Maintenance bypass mode, Functional description, 1 input rectifier – Powerware 9330 User Manual

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

164201300 REV. G 061502

CB1

CB2

Open

Closed

Breakers Contactors

Main Power Flow

Energized

De--Energized

Trickle Current

RECTIFIER

STATIC

SWITCH

BOOST

CONVERTER

INVERTER

MAINTENANCE BYPASS MODE

CHARGER

BATTERY

MAINTENANCE

BYPASS SWITCH

MAINTENANCE

BYPASS SWITCH

Figure 6---7. Path of Current Through the UPS in Maintenance Bypass Mode

6.3

Functional Description

The UPS is a true online unit with a series power train. An uncontrolled rectifier

feeds a boost converter, which in turn powers the inverter. The bypass utilizes a

static switch and a maintenance bypass switch is internal to the unit. The unit input

is 3---wire in (plus ground) at the rectifier and 4---wire in (plus ground) at the

bypass, and 4 wire output. The unit does not incorporate any galvanic isolation,

input to output. The battery string comprises 144 cells (288 volts nominal) and is

charged via a buck or boost converter powered from the raw DC IN from the input

rectifier.

6.3.1 Input Rectifier

The Input Rectifier is a full wave bridge uncontrolled rectifier, which produces an

unregulated DC IN Bus. The raw DC at this point will be approximately 290 VDC. A

pre---charge system pre---charges the DC IN Bus prior to the input contactor being

closed.