UNO-PS/1AC/24DC/30W
105516_en_00 PHOENIX CONTACT 18
10.2 Operating power supply units in parallel
Power supply units of the same type can be connected in
parallel to increase both redundancy and power.
Redundant operation
Redundant circuits are suitable for supplying systems which
place particularly high demands on operational safety. If a
fault occurs in the primary circuit of the first power supply
unit, the second device automatically takes over the com-
plete power supply without interruption, and vice versa.
Using a redundancy module, it is possible for two power
supply units of the same type that are connected in parallel
on the output side for redundancy to be decoupled from one
another.
Figure 11 Redundant circuit with redundancy module
Increased performance
Power supply units of the same type can be connected in
parallel to increase the power to n x I
N
. Parallel connection
is recommended if existing systems are to be extended and
the power supply unit that is installed here does not cover
the current consumption of the most powerful load. Other-
wise, the loads should be distributed between individual de-
vices that are independent of one another.
Using a redundancy module, it is possible for two power
supply units of the same type that are connected in parallel
on the output side to increase power to be decoupled from
one another.
Figure 12 Parallel connection to increase power with a
redundancy module
To ensure symmetrical current distribution, all
cable connections from the power supply unit
to the busbar must be the same length and
have the same conductor cross section.
+
I
N
−
+
I
N
−
+
+
−
−
Σ = I
N
+
I
N
−
+
I
N
−
+
+
−
−
Σ =2xI
N
