QS5.DNET Datasheet, PDF (18/21 Pages) PULS GmbH – 24V, 3.8A, NEC CLASS 2, DEVICENET POWER SUPPLY

Q-Series
QS5.DNET
24V, 3.8A, NEC CLASS 2, DEVICENET^® POWER SUPPLY
24. APPLICATION NOTES
24.1. 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
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. 24-1 Peak load with 2x the nominal
current for 50ms, typ.
Output
24V
Voltage
20V
7.6A
Fig. 24-2 Peak load with 4x the nominal
current for 5ms, typ.
24V
Output
Voltage
17.5V
15A
Output
0A
Current
10ms/DIV
Output
0A
Current
1ms/DIV
Peak load 7.6A (resistive) for 50ms
Output voltage dips from 24V to 20V.
Peak load 15A (resistive) for 5ms
Output voltage dips from 24V to 16V.
Please note: The DC-OK relay triggers when the voltage dips more than 10% for longer than 1ms.
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 28Vdc. The absorbing energy can be calculated according to the built-in
large sized output capacitor which is specified in chapter 6.
Mar. 2013 / Rev. 2.2 DS-QS5.DNET-EN
All parameters are specified at 24V, 3.8A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone [phone] Germany
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