Rockwell Automation 1606-XLP15A Power Supply Reference Manual - Manual (Page 19)

All parameters are specified at 5V, 3A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless noted otherwise.
Rockwell Automation Publication 1606-RM019A-EN-P — March 2014 19
Bulletin 1606 Switched Mode Power Supplies
20.5. Parallel Use for Redundancy
Power supplies 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 power supply unit fails. The simplest way is to put two
power supplies in parallel. This is called a 1+1 redundancy. In case one power supply 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 power supplies, each rated for 3A are paralleled to build a 12A
redundant system.
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 power supply. In such a case, the failing unit becomes a load for the other power supplies
and the output voltage can no longer be maintained. This can only be avoided by using decoupling diodes
which are included in the decoupling module 1606-XLPRED.
Recommendations for building redundant power systems:
a) Use separate input fuses for each power supply.
b) Monitor the individual power supply units.
c) 1+1 Redundancy is allowed up to an ambient temperature of 60°C
N+1 Redundancy is allowed up to an ambient temperature of 45°C
d) It is desirable to set the output voltages of all units to the same value (± 100mV) or leave it at the factory setting.
20.6. Series Operation
Power supplies of the exact 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 150Vdc. Voltages
with a potential above 60Vdc are not SELV any more and can be dangerous.
Such voltages must be installed with a protection against touching. Grounding
the output is required when the sum of the output voltage is above 60Vdc.
Avoid return voltage (e.g. from a decelerating motor or battery) which is
applied to the output terminals. Keep an installation clearance of 15mm (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 (input terminals on the bottom and output terminals on
top of the unit). Please note that leakage current, EMI, inrush current and harmonics will increase when using multiple
power supplies.
Earth
Unit A
AC
DC
Unit B
AC
DC
-
+
-
+
Load
+
-
20.7. Inductive and Capacitive Loads
The unit is designed to supply unlimited inductive loads.
The max. capacitive load depend on the steady state output current. At 3A output current, the output capacity should
not be larger than 10 000μF and at 0.3A output current not larger than 25 000μF. In case of larger capacitors, the unit
can show start-up attempts or start-up problems.