Puls CD5.241 Application Information
CD5.241
CD-Series
DC/DC Converter 24V, 5A
22. APPLICATION NOTES
22.1. PEAK CURRENT CAPABILITY
Solenoids, contactors and pneumatic modules often have a steady state coil and a pick-up coil. The inrush current
demand of the pick-up coil is several times higher than the steady-state current and usually exceeds the nominal
output current (including the PowerBoost) The same situation applies, when starting a capacitive load.
Branch circuits are often protected with circuit breakers or fuses. In case of a short or an overload in the branch circuit,
the fuse needs a certain amount of over-current to trip or to blow. The peak current capability ensures the safe
operation of subsequent circuit breakers.
Assuming the input voltage is turned on before such an event, the built-in large sized output capacitors inside the
DC/DC converter can deliver extra current. Discharging this capacitor causes a voltage dip on the output. The following
two examples show typical voltage dips:
Fig. 22-1 Peak loading with 2x the nominal
24V
current for 50ms, typ.
10A
Output
Voltage
18V
Fig. 22-2 Peak loading with 4x the nominal
current for 5ms, typ.
24V
Output
Voltage
20A
11.5V
0A
Peak load 10A (resistive load) for 50ms
Output voltage dips from 24V to 18V.
10ms/DIV
Output
Current
0A
Peak load 20A (resistive load) for 5ms
Output voltage dips from 24V to 11.5V.
1ms/DIV
Output
Current
22.2. BACK-FEEDING LOADS
Loads such as decelerating motors and inductors can feed voltage back to the DC/DC converter. This feature is also
called return voltage immunity or resistance against Back- E.M.F. (E
This DC/DC converter is resistant and does not show malfunctioning when a load feeds back voltage to the DC/DC
converter. It does not matter, whether the DC/DC converter is on or off.
The maximum allowed feed-back-voltage is 30Vdc. The absorbing energy can be calculated according to the built-in
large sized output capacitance which is specified in chapter 5.
lectro Magnetic Force).
22.3. INDUCTIVE AND CAPACITIVE LOADS
The unit is designed to supply any kind of loads, including unlimited capacitive and inductive loads.
Oct 2009 / Rev. 1.3 DS-CD5.241-EN
All parameters are specified at 24V, 5A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany
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CD5.241
CD-Series
DC/DC Converter 24V, 5A
22.4. CHARGING OF BATTERIES
The DC/DC converter can be used to charge lead-acid or maintenance free batteries. (Two 12V batteries in series)
Instructions for charging batteries:
a) Ensure that the ambient temperature of the DC/DC converter is below 45°C
b) Do not use DC/DC converters in mounting orientations other than the standard mounting orientation (input
terminals on the bottom and output terminals on top of the unit).
c) 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
d) Use a 6A or 10A circuit breaker (or blocking diode) between the DC/DC converter and the battery.
e) Ensure that the output current of the DC/DC converter is below the allowed charging current of the battery.
f) Use only matched batteries when putting 12V types in series.
g) The return current to the DC/DC converter (battery discharge current) is typ. 26.4mA when the DC/DC converter is
switched off (except in case a blocking diode is utilized).
22.5. EXTERNAL INPUT PROTECTION
The unit is tested and approved for branch circuits up to 50A. 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 10A B- or 8A C-Characteristic breaker should be used.
22.6. REQUIREMENTS FOR THE SUPPLYING SOURCE
In certain circumstances, the input filter of the DC/DC converter can show a resonant effect which is caused by the
supplying network. Especially when additional external input filters are utilized, a superimposed AC voltage can be
generated on the input terminals of the DC/DC converter which might cause a malfunction of the unit. Therefore,
additional input filters are not recommended. To avoid the resonant effects, the minimal resistance of the supplying
network which depends on the inductance of the input network, shall be above the boundary curve in Fig. 22-3.
Fig. 22-3 External input filter requirements to
Resistance of the
supplying network
100 mOhm
10 mOhm
1 mOhm
avoid filter instabilities
1 Ohm
0.1mH 1mH 10mH
Inductance of the supplying network
a
)
(
b
(
)
(a) max.
(b) typ.
Oct 2009 / Rev. 1.3 DS-CD5.241-EN
All parameters are specified at 24V, 5A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany
18/21
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