Rockwell Automation 1606-XLE480EPC Power Supply Reference Manual - Manual (Page 21)

Rockwell Automation Publication 1606-RM001B-EN-P - August 2013 21
Bulletin 1606 Switched Mode Power Supplies
23.5 Parallel Use to Increase Output Power
The 1606-XLE480EP power supplies can be paralleled to increase the output power. The
output voltage of all power supplies shall be adjusted to the same value (±100mV) in “Single
use” mode with the same load conditions on all units, or the units can be left with the factory
settings. After the adjustments, the jumper on the front of the unit shall be moved from
“Single use” to “Parallel use”, in order to achieve load sharing. 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
Output on page 6 . If no jumper is plugged in, the unit is in
“Single use” mode. Factory setting is “Single use” mode.
If more than three units are connected in parallel, a fuse or circuit breaker with a rating of 30A or 32A is required on each output. Alternatively, a diode
or redundancy module can also be utilized.
Energize all units at the same time to avoid the overload Hiccup
PLUS
mode. It also might be necessary to cycle the input power (turn-off for at least five
seconds), if the output was in Hiccup
PLUS
mode due to overload or short circuits and the required output current is higher than the current of one unit.
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 parallel in mounting orientations other than the standard mounting orientation (terminals on bottom of the unit) or in any other
condition where a derating of the output current is required (e.g. altitude, above 60°C, …).
Pay attention that leakage current, EMI, inrush current, harmonics will increase when using multiple power supplies.
23.6 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 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 23.5,
Parallel Use to Increase Output Power .
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 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 22.3-
Redundancy Modules on page 18 .
Recommendations for building redundant power systems:
Use separate input fuses for each power supply.
Set the power supply into “Parallel use” mode.
Monitor the individual power supply units. Therefore, use the DC-OK relay contact of the XLE480EP power supply.
It is desirable to set the output voltages of all units to the same value (± 100mV) or leave it at the factory setting.
Unit A
AC
DC
Unit B
AC
DC
-
+
-
+
Load
+
-