20
21
-1
1
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Power Supply PS1000-A6-24.5
Application Notes
25
Application Notes
25.1
Peak Current Capability
The unit can deliver peak currents (up to several milliseconds) which are higher
than the specified short term currents.
This helps to start current demanding loads. 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. The same situation applies when starting a capacitive load.
The peak current capability also ensures the safe operation of subsequent circuit breakers
of load circuits. The load branches are often individually protected with circuit breakers
or fuses. In case of a short or an overload in one branch circuit, the fuse or circuit breaker need
a certain amount of over-current to open in a timely manner. This avoids voltage loss
in adjacent circuits.
The extra current (peak current) is supplied by the power converter and the built-in large sized
output capacitors of the power supply. The capacitors get discharged during such an event,
which causes a voltage dip on the output. The following examples show typical voltage dips
for resistive loads:
Figure 25.1 10A peak current for 50ms , typ. (2x the nominal current)
Figure 25.2 25A peak current for 5ms , typ. (5x the nominal current)
10ms/DIV
Output
Voltage
Output
Current
24V
0A
10A
16V
1ms/DIV
Output
Voltage
Output
Current
24V
0A
25A
14V
