QTD20.241
Q-Series
24V,
20A,
DC
I
NPUT
21.7.
P
ARALLEL
U
SE TO
I
NCREASE
O
UTPUT
P
OWER
DC/DC converters and power supplies from the same series (Q-Series) can be
paralleled to increase the output power. The output voltage shall be adjusted
to the same value (±100mV) or the units can be left with the factory settings.
25/27
If more than three units are connected in parallel, a fuse or circuit breaker
with a rating of 25A is required on each output. Alternatively, a diode or
redundancy module can also be utilized.
Keep an installation clearance of 15mm (left / right) between two power
supplies and avoid installing the DC/DC converters or power supplies on top of
each other. Do not use DC/DC converters or power supplies in parallel in
mounting orientations other than the standard mounting orientation (input
terminals on the bottom of the unit) or in any other condition where a derating of the output current is required (e.g.
altitude, above 60°C, …).
Unit B
-
+
Load
+
-
-
+
Unit A
Input
Output
Input
Output
Pay attention that leakage current, EMI, inrush current, harmonics will increase when using multiple DC/DC converters.
21.8.
P
ARALLEL
U
SE FOR
R
EDUNDANCY
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
connect 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 converters, each rated for 20A are paralleled to build
a 80A redundant system. For N+1 redundancy the same restrictions apply as for increasing the output power, see also
chapter 21.7.
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 power
supplies 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 chapter 20.4.
Recommendations for building redundant power systems:
a)
Use separate input fuses for each
DC/DC converter. A separate source for each supply when possible increases the
reliability of the redundant system.
b)
Monitor the individual DC/DC converter units. Therefore, use the DC-OK relay contact of the QTD20.241.
c)
It is desirable to set the output voltages of all units to the same value (± 100mV) or leave it at the factory setting.
21.9.
I
NDUCTIVE AND
C
APACITIVE
L
OADS
The unit is designed to supply any kind of loads, including capacitive and inductive loads.
Oct. 2016 / Rev. 2.0 DS-QTD20.241-EN
All parameters are specified at 24V, 20A, 600Vdc input, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany