ML15.121
MiniLine
12V, 1.3A, S
INGLE
P
HASE
I
NPUT
Dec. 2007 / Rev. 1.1 DS-ML15.121-EN
All parameters are specified at 12V, 1.3A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany
15/20
25. A
PPLICATION
N
OTES
25.1. P
EAK
C
URRENT
C
APABILITY
Solenoids, contactors and pneumatic modules often have a steady state (sealed) 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. 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 protective device (fuse, circuit breaker) 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
power supply can deliver extra current. Discharging this capacitor causes a voltage dip on the output. The following
two examples show typical voltage dips:
Fig. 25-1
Peak load 2.6A for 50ms, typ.
Fig. 25-2
Peak load 6.5A for 5ms, typ.
10ms/DIV
Output
Voltage
Output
Current
12V
0A
2.6A
7.8V
1ms/DIV
Output
Voltage
Output
Current
12V
0A
6.5A
2V
Peak load 2.6A (resistive) for 50ms
Output voltage dips from 12V to 7.8V.
Peak load 3.15A (resistive) for 5ms
Output voltage dips from 12V to 2V.
25.2. B
ACK
-
FEEDING
L
OADS
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).
The maximum allowed feed back voltage is 25Vdc. The absorbing energy can be calculated according to the built-in
large sized output capacitor which is specified in chapter 9.
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. However, please note that the output voltage can
dip to zero for approximatelly 200ms if the back-feed voltage is removed.
25.3. I
NDUCTIVE AND
C
APACITIVE
L
OADS
The unit is designed to supply unlimited inductive loads. The max. capacitive load depend on the steady state output
current. At 1.3A output current, the output capacity should not be larger than 1000µF at 0.65A output not larger
than 2500µF. In case of larger capacitors, the unit can show start-up attempts or start-up problems.
