2 PSU In series question.

Hi Guys I have a 24v motor attached to a 90w switching PSU stepping down from 240VAC.

I want to power my arduino from a 240VAC to 5vdc premade PCB.

The problem is, the way this is all configured means (Please see attached circuit diagram) I only have access to the lower portion of the circuit diagram. IE the neutral wire and switch part (housed in an external control box).

As such I cannot connect the 5V PSU PCB in parallel.

Would I be OK to connect the two PSUs in series? What considerations would be needed?

All help appreciated

Krish

In series voltages add. Secondly in no way shape or fashion connect the Arduino to any portion of a mains circuit. If you are lucky, you only detonate your PC and your Arduino, bad luck you get electrocuted as well. Put your switch on the 5 volt side in series with the Arduino. With a 5V supply you will need to apply your power to the board at the 5V and Gnd pins on the power header. 7V is the minimum voltage when powering via the coax jack.

So if the two Power supply boards were supplied in series, the 240VAC is divided between the two? Neither board will receive a full 240vac?

The mains side is paralleled, poth psu get their designed run voltage of 240VAC. You are being a little vague in describing what you are really seeking to do.

widget: So if the two Power supply boards were supplied in series, the 240VAC is divided between the two? Neither board will receive a full 240vac?

Not only that, one would dominate, the other would get a pittance, since they are wanting very different power levels.

No power circuit should be switched on just the neutral side BTW, that's highly dangerous. Note that the neutral is not safe, you must assume it can be at full mains voltage, since that's exactly what happens in many failure modes.