20
Rockwell Automation Publication 1606-RM121A-EN-P - October 2020
Series Operation
Devices of the same type can be connected in series for higher output voltages.
It is possible to connect as many units in series as needed, providing the sum
of the output voltage does not exceed 150V DC. Voltages with a potential above
60V DC must be installed with a protection against touching.
Avoid return voltage (for example, from a decelerating motor or battery) which
is applied to the output terminals.
Keep an installation clearance of 15 mm (0.59 in.) (left / right) between two
power supplies and avoid installing the power supplies on top of each other.
Do not use power supplies in series in mounting orientations other than the
standard mounting orientation.
Leakage current, EMI, inrush current, and harmonics increase when using
multiple devices.
Figure 26 - Series Operation
Parallel Use for 1+1
Redundancy
Devices can be paralleled for 1+1 redundancy to gain higher system availability.
Redundant systems require a certain amount of extra power to support the
load in case one device fails. The simplest way is to put two devices in parallel.
This is called a 1+1 redundancy. In case one device fails, the other one is
automatically able to support the load current without any interruption. It is
essential to use a redundancy module to decouple devices from each other.
This helps prevent the defective unit from becoming a load for the other
device, which helps to ensure that the output voltage can be maintained.
A means to report a defective or non-functional power supply is essential for
redundant systems. This power supply does not incorporate such means of
reporting. So if you use it for 1+1 redundancy, use it with a redundancy module
that monitors and reports insufficient input voltage.
Alternatively, you could use another model of power supply that has a DC OK
signal included. With a DC OK signal, you would not need the redundancy
module to have the monitoring and reporting feature.
Unit A
Input
Output
Unit B
-
+
-
+
Load
+
-
Input
Output
