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E-51028230XT/BG - 11
Parallel UPSs with
redundancy
◗ the shutdown of one UPS unit is of
no consequence for the load. The
others each take up an equal amount of
load power and the load continues to
be supplied normally;
Unit shutdown results in the following
on the control panel:
◗◗ lights 4 and 5 go off,
◗◗ activation of the buzzer (continuous
beep),
◗◗ the message "LOAD NOT
PROTECTED, PARALLEL ON-LINE
MODE" is displayed;
◗ in the event of an overload, the
system only loses its redundancy as
long as the overload is less than the
total rated power of the functioning
units. If the overload is greater, the
operating mode is that previously
described for systems without
redundancy.
Frequency converters
◗ in the event of a shutdown, the load
is no longer supplied with power;
◗ in the event of a major transient
overload (greater than 1.65 In), the
inverter will current limit to 165% of
their rated current for 1 second before
stopping;
◗ in the event of a smaller but
prolonged overload, the inverter
respects the same overload curve as
the single inverter and shuts down;
◗ in all three of the above cases,
inverter shutdown results in the
following:
◗◗ lights 4 and 5 go off,
◗ ◗ activation of the buzzer (continuous
beep),
◗◗ the message "LOAD NOT
PROTECTED, ON-LINE MODE" is
displayed.
Inverter shutdown or
overload
See figure 13 for devices or
installations operating in on-line mode
with a bypass AC source.
If the conditions are not satisfied, the
inverter will current limit to 165% of its
rated current for 1 second before
stopping;
◗ in the event of a small but extended
overload (i.e. a continuous level of
power exceeding the full rated load),
the inverter will continue to supply
power for a period depending on the
magnitude of the overload (10 minutes
for a 125% overload, 1 minute for a
150% overload). See the overload
curve in figure 14;
◗ in all three of the above cases,
inverter shutdown and supply of the
load via the bypass AC source results
in the following on the control panel:
◗◗ light 4 goes off,
◗ ◗ activation of the buzzer (continuous
beep),
◗ ◗ light 3 shines green,
◗ ◗ the message "LOAD NOT
PROTECTED, ON-LINE MODE" is
displayed.
Parallel UPSs without
redundancy
The shutdown of one inverter results in
overload on the other inverters in
operation. Two cases may then arise:
◗ if the overload on each remaining
inverter is > than 1.65 ln, the load is
immediately transferred to the bypass
AC source;
◗ if the overload is less than 1.65 ln,
the remaining inverters support the
overload (see curve in figure 14), and
the load is transferred to the bypass AC
source;
◗ after this transfer:
◗◗ the light 4 goes off,
◗ ◗ the buzzer is activated and sounds
continuously,
◗ ◗ the light 3 goes on and turns green,
◗◗ the message "LOAD NOT
PROTECTED, PARALLEL ON-LINE
MODE" is displayed.
Single-UPS unit (on-line or
"ECO" mode)
◗ in the event of a UPS shutdown
(initiated by the user or by an internal
protective device), the load is
automatically transferred to the bypass
AC source. If transfer conditions are
satisfied, transfer takes place instantly,
without interruption to the load;
Note: transfer conditions are not
satisfied when bypass AC source
characteristics are outside tolerances
(voltage: ±10%; frequency as per
personalisation; phase sync with
inverter ±3°);
◗ in the event of a major transient
overload (greater than 1.65 In),
immediate transfer takes place as
above, without interruption to the load.
The return to the inverter is automatic
when the overload disappears if the
number of possible returns has not
been reached (0 to 255, programmable
by personalisation). If this number has
been reached, the load continues to be
supplied by the bypass AC source. This
operating mode allows start-up of load
devices causing high inrush currents.
This system requires satisfied transfer
conditions.
Fig. 13
2
1
1
2
AB
C
D
3 5
Fig. 14
I
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(min)
1,5 In
1,35 In
1,25 In
1,15 In
1,10 In
1,05 In
In
t
30 120
Introduction (cont.)