Maintenance Bypass Mode; Functional Description; Input Rectifier - Powerware 9330 Installation & Operation Manual

MAINTENANCE
BYPASS SWITCH
CB1 K1
Breakers Contactors
Figure 7 ---7. Path of Current Through the UPS in Maintenance Bypass Mode
7.3

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.
7.3.1

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
precharge system precharges the DC IN Bus prior to the input contactor being
closed.
7--12

MAINTENANCE BYPASS MODE

STATIC
K5
SWITCH
RECTIFIER
CHARGER
Closed
Open
BATTERY
BOOST
CONVERTER
K2
CB2
Powerware 9330 (IBM 9910 20 kVA) Installation and Operation
INVERTER
K3
MAINTENANCE
BYPASS SWITCH
Main Power Flow
Trickle Current
Energized
De- -Energized
164201491 REV. B 013004