Normal Mode - Rt; Figure 7-2. Path Of Current Through The Ups In Normal Mode - Rt - Eaton Powerware 9390 Installation And Operation Manual

7.1.2 Normal Mode – RT
Figure 7‐2 shows the path of electrical power through the UPS system when the UPS
is operating in Normal mode.
Rectifier Rectifier
K1 K1
Breakers Breakers Contactors Contactors
Closed Closed
Open Open
During normal UPS operation, power for the system is derived from a utility input
source through the rectifier input contactor K1. The front panel displays "Normal,"
indicating the incoming power is within voltage and frequency acceptance windows.
Three-phase AC input power is converted to DC using IGBT devices to produce a
regulated DC voltage to the inverter. The battery is charged directly from the
regulated rectifier output through a buck or boost DC converter, depending on
whether the system is 208V, 380V, 400V, 415V, or 480V and the size of the battery
string attached to the unit.
The battery converter derives its input from the regulated DC output of the rectifier
and provides either a boosted or bucked regulated DC voltage charge current to the
battery. The UPS monitors the battery charge condition and reports the status on the
control panel. The battery is always connected to the UPS and ready to support the
inverter should the utility input become unavailable.
®
EATON Powerware 9390 UPS (20–80 kVA) Installation and Operation Manual
Static Static
K5 K5
Switch Switch
Battery Battery
Converter Converter
Battery Battery
Breaker Breaker
Battery Battery
Figure 7‐2. Path of Current Through the UPS in Normal Mode – RT
UNDERSTANDING UPS OPERATION
Inverter Inverter
Main Power Flow Main Power Flow
Trickle Current Trickle Current
Energized Energized
De-Energized De-Energized
S
164201603 Rev 2 www.powerware.com
K3 K3
7-3