I have a project about to mantain a data log of a 3 phase motor, when the more is on and off count that time and save in memory location.

I don't use any server now to save data, I use a Rpi to do all this stuff. Any other controller I can use suggest please.

I want that 3 phase signal on my Rpi when the switch is on, 1- 3 phase AC to 3.3v dc signal? Thank you.

  • \$\begingroup\$ Are you trying to power the pi from it? \$\endgroup\$
    – Andy aka
    Aug 7, 2020 at 12:47
  • \$\begingroup\$ use a current sensor \$\endgroup\$
    – Juraj
    Aug 7, 2020 at 13:22
  • \$\begingroup\$ Not actually, I power it from battery but I want to use a charger from that voltage signal comming from 3Phase AC.. \$\endgroup\$ Aug 7, 2020 at 16:32
  • \$\begingroup\$ Which current sensor please mention.. Thanks \$\endgroup\$ Aug 7, 2020 at 16:33

1 Answer 1


Use a relay.


simulate this circuit – Schematic created using CircuitLab

Figure 1. A possible circuit.

The relay separates your 3-phase from your 3.3 V Raspberry Pi circuit making it a safe system.


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