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Rockwell Automation Publication 1606-RM110A-EN-P - July 2020
Redundancy Power Supply - 24V, 10 A, 240 W, Single-phase Input
Parallel Use to Increase Output Power
Power supplies can be paralleled to increase the output power. For redundancy
applications one extra power supply is always needed for sufficient output
current in case one unit fails.
The unit is permanently set to “parallel use” mode in order to achieve load
sharing between power supplies connected in parallel. 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
Energize all units at the same time. It also might be necessary to cycle the
input power (turn-off for at least 5 seconds), if the output was in overload or
short circuits and the required output current is higher than the current of one
unit.
Keep an installation clearance of 15 mm (left / right) between two power
supplies and avoid installing the power supplies on top of each other.
Do not use power supplies in parallel in mounting orientations other than the
standard mounting orientation (input terminals on bottom of the unit) or in
any other condition where a derating of the output current is required (for
example, altitude).
Pay attention that leakage current, EMI, inrush current, harmonics will
increase when using multiple power supplies.
Do not load paralleled power supplies with higher currents as shown in the
following diagrams:
Figure 36 - Output Current Versus Ambient Temperature for Two
Paralleled Units
Figure 37 - Output Current Versus Ambient Temperature for Three
Paralleled Units
Allowed output current for two paralleled units
24A
0
30
40
50
60
70°C
4A
8A
12A
16A
20A
B
A
Ambient Temperature
A... continuous
B... short term (max. 5s)
36.6
14A
Allowed output current for three paralleled units
36A
0
30
40
50
60
70°C
6A
12A
18A
24A
30A
B
A
21A
A... continuous
B... short term (max. 5s)
36.6
Ambient Temperature