Datasheet

CPS20.481-D1
C-Series
48V, 10A, DC/DC CONVERTER
22.5. PARALLEL USE TO INCREASE OUTPUT POWER
Unit A
Unit B
-
+
-
+
Load
+
-
Input
Output
Input
Output
CPS20.481-D1 DC/DC converter can be paralleled to increase the output
power. The output voltage of all DC/DC converters shall be adjusted to the
same value (±100mV) in “Single use” mode with the same load conditions on
all units, or the units can be left with the factory settings. After the
adjustments, the jumper on the front of the unit shall be moved from
“Single use” to “Parallel use”, in order to achieve load sharing. The “Parallel
use” mode regulates the output voltage in such a manner that the voltage
at no load is approx. 4% higher than at nominal load. See also chapter 6. If
no jumper is plugged in, the unit is in “Single use” mode. Factory setting is
“Single use” mode.
If more than three units are connected in parallel, a fuse or circuit breaker with a rating of 15A or 16A is required on
each output. Alternatively, a diode or redundancy module can also be utilized.
Energize all units at the same time to avoid the overload Hiccup
PLUS
mode. It also might be necessary to cycle the input
power (turn-off for at least five seconds), if the output was in Hiccup
PLUS
mode due to overload or short circuits and the
required output current is higher than the current of one unit.
Keep an installation clearance of 15mm (left / right) between two DC/DC converters and avoid installing the DC/DC
converters on top of each other. Do not use DC/DC converters in parallel in mounting orientations other than the
standard mounting orientation (terminals on bottom of the unit) or in any other condition where a derating of the
output current is required (e.g. altitude, above 60°C, …).
Pay attention that EMI and inrush current will increase when using multiple DC/DC converters.
22.6. PARALLEL USE FOR REDUNDANCY
DC/DC converters can be paralleled for redundancy to gain higher system availability. Redundant systems require a
certain amount of extra power to support the load in case one DC/DC converter unit fails. The simplest way is to put
two DC/DC converters in parallel. This is called a 1+1 redundancy. In case one DC/DC converter unit fails, the other one
is automatically able to support the load current without any interruption. Redundant systems for a higher power
demand are usually built in a N+1 method. E.g. five DC/DC converter, each rated for 10A are paralleled to build a 40A
redundant system. For N+1 redundancy the same restrictions apply as for increasing the output power, see also
chapter 22.5.
Please note: This simple way to build a redundant system does not cover failures such as an internal short circuit in
the secondary side of the DC/DC converter. In such a case, the defective unit becomes a load for the other DC/DC
converters and the output voltage can not be maintained any more. This can be avoided by utilizing redundancy
modules, which have decoupling devices (diodes or mosfets) included. Further information and wiring configurations
can be found in chapter21.3.
Recommendations for building redundant power systems:
a) Use separate input fuses for each DC/DC converter.
b) Set the DC/DC converter into “Parallel use” mode.
c) Monitor the individual DC/DC converter units. Therefore, use the DC-OK relay contact of the CPS20 DC/DC
converter.
d) It is desirable to set the output voltages of all units to the same value (± 100mV) or leave it at the factory setting.
Oct. 2013 / Rev. 1.2 DS-CPS20.481-D1-EN
All parameters are specified at 48V, 10A, 300Vdc, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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