5.2 Single UPS
A single UPS
operates independently
to
support
an applied load from the
inverter,
providing
conditioned and
uninterruptible
AC
power
to the critical load from the
output
of the
module.
During
an
outage,
the inv
erter
continues
to
operate, supporting power
to the load from the
battery
supply. If
the unit
requires service, app
lied
loads are
transferred
to the internal
bypass
either
automatically
or
manually. With the
exception
of an
optional
external battery cabinet,
no other
cabinets
or
equipment
are
required
for the single UPS to
successfully
support
its applied
loads.
5.2.1 Modes
The Eaton 93E MK2 UPS
supports
a critical load in four
different modes
of
operation:
•
In
Standard
Normal
mode,
the critical load is
supplied
by the
inverter,
which
derives
its
power
from
rectified
utility AC
power.
In this
mode,
the
battery charger
also
provides
charging
current
for the
battery,
if
needed,
Standard mode
is the
standard
normal
operating
mode.
•
In High-Efficiency (HE)
mode, commercial
AC
power
is
supplied
directly to the critical load
through
the
internal
bypass
and
transfers automatically
to
Standard
Normal
mode (double-
conversion
on
demand)
if
an
abnormal
condition is
detected.
Note：Need to enable HE mode from LCD
•
In
Bypass mode,
the critical load is directly
supported
by utility
po
w
er
.
•
In Battery
mode,
the
battery provides
DC
power,
which
maintains
inverter
operation.
The
battery
supports
the critical
load.
The following
paragraphs describe
the
differences
in the UPS
operating modes,
using block
diagrams
to
show
the
power
flow during each
mode
of
operation.
5.2.2
High-Efficiency Mode
When the UPS is
operating
in HE
mode, commercial
AC
power
is
supplied
directly to the critical load
through
the
internal
b
ypass
with the
po
w
er
module
in a
st
andb
y
st
ate.
If
a
commercial
po
w
er
bro
wnout,
blackout,
o
v
er
v
olt
age,
under voltage,
or
out-of-tolerance frequency
condition
occurs
the
system
forward
transfers
to
normal
mode
(double-conversion
on
demand)
or
battery
mode.
When the input line
returns
to normal
operating
range, the
UPS
returns
to HE
operation.
For charging
batteries
in HE
mode,
the UPS will revert to normal
mode
to
charge
the
batteries,
then return to HE
mode when charge
cycle is
complete.
HE
mode,
if
selected,
is a normal
operating mode,
and not an alarm condition. While the UPS is in this
mode,
the NORMAL light on the front display will
illuminate.
5.2.3
Standard Normal
Mode
During
Standard
Normal
mode, power
for the
system
is derived from a utility input
source through
the
rectifier
input
cont
actor.
T
hree-phase
AC input
power
is
converted
to DC using
IGBT
devices
to
produce
a
regulated
DC voltage to the
inverter.
When the
battery contactor
is
closed
the
battery
is
charged
directly from the
regulated
rectifier
output through
a buck or
boost
DC
converter, depending
on the
system
voltage and the size of
the
battery
string
attached
to the
unit.
Figure 5-2
shows
the path of electrical
power through
the UPS
system when
the UPS is
operating
in
Normal
mode.
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
bat
ter
y
.
The
battery
is
always
connected
to
the
UPS and ready to
support
the inverter should the utility input
become
una
v
ailable.
The inverter
produces
a
three-phase
AC
output
to a
customer's
load
without
the use of a
transf
ormer.
T
he
inverter
derives regulated
DC from the rectifier and
uses
IGBT
devices
and
pulse-width
modulation
(PWM)
to
produce
a
regulated
and filtered AC
output.
The AC
output
of the inverter is
delivered
to the
system output
through
the
output cont
actor.
Eaton 93E MK2 UPS (10-40kVA, 380/400/415V) Installation and Operation
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