6739389EN/FB - Page 19
UPS theory of operation (continued)
Parallel connected UPS with "Static Switch" cubicle
Up to six parallel connected
rectifier-inverter cubicles can be
combined with one "Static Switch"
cubicle to form a system that
operates like a unitary UPS system.
Each parallel connected rectifier-
inverter cubicle houses a:
◗ rectifier-charger;
◗ battery;
◗ three-phase inverter.
The "Static Switch" cubicle
contains:
◗ static by-pass switch;
◗ maintenance bypass.
The units have separate batteries:
Mains 1
rectifier-
charger
battery
inverter
load
static by-pass switch
Mains 2
Mains 1
rectifier-
charger
battery
inverter
UPS without Mains 2
All UPSs without Mains 2 contain
the same sub-assemblies:
◗ rectifier-charger;
◗ battery (option);
◗ three-phase inverter.
They may or may not be parallel
connected depending on type and
may or may not contain a battery.
The output voltage has a frequency
of 50 or 60 Hz.
Operation without battery
Mains 1 power up:
◗ the inverter receives power from
the rectifier-charger and supplies
power to the load. There is no
direct connection between Mains 1
and the load.
load
Mains 1
rectifier-
charger inverter
Mains 1 power down:
◗ no power to the load.
Maintenance position
(disconnected):
◗ no power to the load (except in
parallel connected systems, where
other units supply power).
load
Mains 1
rectifier-
charger inverter
Q1 Q5N
load
Mains 1
rectifier-
charger inverter