Rockwell Automation 1606-XLS240F, -XLS240F-D Power Supply Reference Manual - Manual (Page 23)

All parameters are specified at 48V, 5A, 230Vac, 25°C ambient and after a 5 minutes run-in time, unless noted otherwise.
Rockwell Automation Publication 1606-RM045A-EN-P — March 2014 23
Bulletin 1606 Switched Mode Power Supplies
23.5. Charging Batteries
The power supply can be used to charge lead-acid or maintenance free batteries. (Four 12V batteries in series)
Instructions for charging batteries:
a) Set output voltage (measured at no load and at the battery end of the cable) very precisely to the end-of-charge
voltage.
End-of-charge voltage 55.6V 55.0V 54.3V 53.6V
Battery temperature 10°C 20°C 30°C 40°C
b) Use a 10A circuit breaker (or blocking diode) between the power supply and the battery.
c) Ensure that the output current of the power supply is below the allowed charging current of the battery.
d) Use only matched batteries when putting 12V types in series.
e) The return current to the power supply (battery discharge current) is typ. 4mA when the power supply is switched
off (except if using a blocking diode).
23.6. Output Circuit Breakers
Standard miniature circuit breakers (MCBs or UL 1077 circuit breakers) are commonly used for AC-supply systems and
may also be used on 48V branches.
MCBs are designed to protect wires and circuits. If the ampere value and the characteristics of the MCB are adapted to
the wire size that is used, the wiring is considered as thermally safe regardless of whether the MCB opens or not.
To avoid voltage dips and under-voltage situations in adjacent 24V branches which are supplied by the same source, a
fast (magnetic) tripping of the MCB is desired. A quick shutdown within 10ms is necessary corresponding roughly to
the ride-through time of PLCs. This requires power supplies with higfh current reserves and large output capacitors.
Furthermore, the impedance of the faulty branch must be sufficiently small in order for the current to actually flow.
The best current reserve in the power supply does not help if Ohm’s law does not permit current flow. The following
table has typical test results showing which B- and C-Characteristic MCBs magnetically trip depending on the wire cross
section and wire length.
Fig. 24-5 Test circuit Maximal wire length *) for a fast (magnetic) tripping:
0.75mm² 1.0mm² 1.5mm² 2.5mm²
C-2A 58m 64m 104m 143m
C-3A 41m 53m 73m 124m
C-4A 18m 31m 54m 94m
C-6A 10m 14m 21m 33m
C-8A 4m 6m 8m 13m
C-10A 3m 4m 7m 10m
B-6A 19m 28m 39m 75m
B-10A 8m 12m 16m 29m
MCB Power Supply
AC
DC
+
-
Load
+
-
B-13A 7m 9m 13m 23m
Wire length
S1... Fault simulation switch
S1
*) Don’t forget to consider twice the distance to the load (or cable length) when calculating the total wire length (+ and – wire).