Rockwell Automation 1606-XLE960MX-3N Power Supply Reference Manual - Manual (Page 19)

All parameters are specified at 48V, 20A, 3x480Vac, 25°C ambient and after a 5 minutes run-in time, unless noted otherwise.
Rockwell Automation Publication 1606-RM025A-EN-P — April 2014 19
Bulletin 1606 Switched Mode Power Supplies
25.4. External Input Protection
The power supply does not include any internal input fuse. The unit is tested and approved for branch circuits up to 16A
(U.S.A 15A). External protection is required o n l y i f the supplying branch has an ampacity greater than this. In some
countries local regulations might apply; do check all local codes and requirements. If an external fuse is necessary or
utilized, minimum requirements need to be considered to avoid nuisance tripping of the fuse.
c i t s i r e t c a r a h C - C c i t s i r e t c a r a h C - B
Ampacity max. 20A 20A
min. 6A 3A
25.5. Back-feeding Loads
Loads such as decelerating motors and inductors can feed voltage back to the power supply. This feature is also called
return voltage immunity or resistance against Back-EMF (Electro Magnetic Force).
This power supply is resistant and does not show adverse effects when a load feeds back voltage to the power supply.
It does not matter whether the power supply is on or off.
If the power supply is fully loaded after a return-feeding event, the output voltage can dip to 21V for approx. 20ms.
The maximum allowed feed back voltage is 55.1Vdc. The absorbing energy can be calculated according to the built-in
large sized output capacitor which is specified in section 7.
25.6. Parallel Use to Increase Output Power
The power supply shall not be used in parallel to increase output power.
25.7. Parallel Use for Redundancy
Power supplies can be paralleled for a 1+1 redundancy to gain a higher system availability and reliability. 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 1606-XLE power supplies in parallel ( a method called 1+1 redundancy). In case one power supply fails,
the second is automatically able to support the load current without any interruption.
Please note:
This simple way to build a redundant system does not cover such failures as an internal short circuit on
the secondary side of the power supply. In such a condition, the shorted unit becomes a load for the other power
supplies and the output voltage can not be maintained. This can be avoided by using decoupling diodes wich are
included in our redundancy modules (references 1606-XLERED and 1606-XLSRED). One redundancy module per XLE
power supply is required.
Recommendations for building redundant power systems:
a)
Use separate input fuses for each power supply.
b) Monitor the individual power supply units. A DC-ok LED and a DC-ok contact are included in some redundancy
modules and are able to report a faulty unit.