Puls CD Series - Output Circuit Breakers; Charging of Batteries

CD10.241
CD-Series
DC/DC Converter 24V/24V, 10A, 240W
Sep. 2019 / Rev. 1.4 DS-CD10.241-EN All values are typical figures specified at 24Vdc input voltage 24V, 10A output load,
25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany
23/27
22.2. OUTPUT CIRCUIT BREAKERS
Standard miniature circuit breakers (MCB’s or UL 1077 circuit breakers) are commonly used for AC-supply systems and
may also be used on 24V branches.
MCB’s 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 PLC's. This requires power supplies with high 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.
The following test results indicate the maximal wire length for a magnetic (fast) tripping. The wire length is always
two times the distance to the load (+ and - wire).
Fig. 22-3 Test circuit for maximum wire length
Test results for maximum wire length:
MCB
DC/DC
Converter
DC
DC
+
-
+
-
Load
Wire length
S1... Fault simulation switch
S1
0.75mm² 1.0mm² 1.5mm² 2.5mm²
C
-2A 23m 25m 41m 71m
C-3A
13m 15m 23m 33m
C
-4A 4m 6m 8m 13m
C
-6A
1m 2m 2m 5m
B
-6A
8m 10m 14m 23m
B
-10A
1m 2m 2m 3m
B
-13A 1m 2m 3m
22.3. CHARGING OF BATTERIES
The device can be used to charge lead-acid or maintenance free batteries. Two 12V SLA or VLRA batteries are needed
in series connection.
Instructions for charging batteries:
a) Ensure that the ambient temperature of the Device is below 45°C.
b) 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 27.8V 27.5V 27.15V 26.8V
Battery temperature 10°C 20°C 30°C 40°C
c) Use a 16A circuit breaker or blocking diode between the Device and the battery.
d) Ensure that the output current of the Device is below the allowed charging current of the battery.
e) Use only matched batteries when putting 12V types in series.
f) The return current to the Device (battery discharge current) is typ. 10mA when the Device is switched off except
in case a blocking diode is utilized.
g) Do not use the devices for battery charging in mounting orientations other than the standard mounting
orientation or in any other condition where a reduction of the output current is required (e.g. altitude).