Strange behavior logo power supply 24v 1.3A

The maximum load of the circuit is 0.5A .. and this problem occurs completely randomly during the normal operation of the machine .. I have not detected absorption peaks during running of the machine .. I have read that this type of power supply has an electronic protection. Does anyone know how this protection works and when it might kick in?

If you are absolutely sure that there is no overload and that all safety diodes on the external relays are OK, then I have only two assumptions:

1. Interference radiation enters the 24 V circuit via the connection to the protective conductor.

or:

2. The smoothing capacitors in the power supply are defective.This is usually easy to see because they have usually become deformed.

Ella_68

Ella_68

If you are absolutely sure that there is no overload and that all safety diodes on the external relays are OK, then I have only two assumptions:

1. Interference radiation enters the 24 V circuit via the connection to the protective conductor.

or:

2. The smoothing capacitors in the power supply are defective.This is usually easy to see because they have usually become deformed.

Ella_68

An oscilloscope or a frequency analyzer might be able to help.

But just try a stronger power supply.

Ella_68

Ventu_97

<snip>
in practice it only worked in no-load condition, as soon as I closed the circuit by inserting a fuse on the +24 line, the power supply interrupted the output and the status led was no longer green.

After a few attempts everything was back to working properly ..

</snip>

Assuming the insertion of the fuse was like having a switch closing..

The description sounds like inrush current. There is a spike of consumption when a device is switched on. This is not always documented well. You may easily see that there is some piece of electronics that pulls more than the supplied power when those were switched off for a while (perhaps as long as 15 minutes). Switching off/on repeatedly will eventually charge the capacitors enough in the electronic device so that the power supply can keep it on.

[https://en.wikipedia.org/wiki/Inrush_current]

Ella_68 said it first.. get a bigger power supply that can handle the switch on.

Ella_68

An oscilloscope or a frequency analyzer might be able to help.

But just try a stronger power supply.

Ella_68

ok..I'll see what I can do .. anyway I don't think it's due to sudden power surges as I only connected a LOGO logic module with its expansion and a 4g 24v modem ..As I repeat, I measured a maximum load of 0.5A

Thank you very much for your support

Maybe a measurement of the current would be a better solution. Depending on your oscilloscope use a shunt resistor 0.1 Ohm in series between power supply and your load. If the oscilloscope input is not isolated, then the resistor must be inserted at the M side of the power supply. Be careful, if the ground of the oscilloscope input is earthed.

Regards, Scorp

Ventu_97

ok..I'll see what I can do .. anyway I don't think it's due to sudden power surges as I only connected a LOGO logic module with its expansion and a 4g 24v modem ..As I repeat, I measured a maximum load of 0.5A

Thank you very much for your support

Just an idea:

4G/LTE Modems requires more current if they transmit. Have you checked if the 4G modem is transmitting, if the 1.3A of your power supply is enought?

Did you try a larger power supply?

What other load is connected to LOGO! and the power supply?

I also believe there is a over load of the power supply and would meassure the current with the oszilloscope and a shunt.