CP10.121 Datasheet, PDF (22/26 Pages) PULS GmbH – SINGLE PHASE INPUT

CP-Series
CP10.121
12V, 16A, SINGLE PHASE INPUT
24.2. 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- E.M.F. (Electro Magnetic Force).
This power supply is resistant and does not show malfunctioning when a load feeds back voltage to the power supply.
It does not matter whether the power supply is on or off.
The maximum allowed feed-back-voltage is 25Vdc. The maximum allowed feed-back peak current is 64A. Higher
currents can temporarily shut-down the output voltage. The absorbing energy can be calculated according to the
built-in large sized output capacitor which is specified in chapter 6.
24.3. EXTERNAL INPUT PROTECTION
The unit is tested and approved for branch circuits up to 30A (UL) and 32A (IEC). An external protection is only
required if the supplying branch has an ampacity greater than this. Check also local codes and local requirements. In
some countries local regulations might apply.
If an external fuse is necessary or utilized, minimum requirements need to be considered to avoid nuisance tripping of
the circuit breaker. A minimum value of 6A B- or C-Characteristic breaker should be used.
24.4. 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 12V 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 12V 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.
Fig. 24-4 Test circuit
Power Supply MCB
AC
+
Wire length
DC ^-
S1... Fault simulation switch
Load
+
S1
-
Maximal wire length^*) for a fast (magnetic) tripping:
0.75mm² 1.0mm² 1.5mm² 2.5mm²
C-2A
11m
15m
22m
35m
C-3A
9m
13m
18m
23m
C-4A
5m
8m
12m
17m
C-6A
-
1m
2m
3m
B-6A
6m
11m
15m
23m
B-10A
2m
3m
3m
4m
B-13A
1m
2m
3m
4m
*) Don’t forget to consider twice the distance to the load (or cable length) when calculating the total wire length (+ and – wire).
Feb. 2016 / Rev. 1.1 DS-CP10.121-EN
All parameters are specified at 12V, 16A, 230Vac, 50Hz, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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