CPS20.481

C-Series

The power supply 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 (including the PowerBoost). 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 two examples show typical voltage dips:

Fig. 22-1 Peak load with 2x the nominal

current for 50ms, typ.

Fig. 22-2 Peak load with 5x the nominal

current for 5ms, typ.

Output

Voltage

21/26

10ms/DIV

Output

Current

48V

0A

20A

32V

Output

Voltage

48V

Output

Current

0A

1ms/DIV

50A

37V

Peak load 20A (resistive) for 50ms

Output voltage dips from 48V to 32V.

Peak load 50A (resistive) for 5ms

Output voltage dips from 48V to 37V.

Please note: The DC-OK relay triggers when the voltage dips more than 10% for longer than 1ms.

Peak current voltage dips

typ.

from 48V to 32V

at 20A for 50ms, resistive load

typ.

from 48V to 39V

at 50A for 2ms, resistive load

typ.

from 48V to 37V

at 50A for 5ms, resistive load

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 63Vdc. The absorbing energy can be calculated according to the built-in

large sized output capacitor which is specified in chapter 6.

Apr. 2014 / Rev. 1.5 DS-CPS20.481-EN

All parameters are specified at 48V, 10A, 230Vac, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.

www.pulspower.com Phone +49 89 9278 0

Germany