3 Phase neutral loss detector

[mtawab74]

Dear All

i have an equipment that's powered by a 3 phase 4 wire source

I'm looking for a circuit that detect if the neutral wire is connected to the instrument or not

looking for your help.

 

[pico]

Monitoring line-to-neutral voltage

 

[mtawab74]

would u give more explanation

 

[flatulent]

If you have equal currents in the three phases, no current will flow through the neutral and there is no way to tell if it is open by measurements on the other three lines.

Your best bet would be solid mechanical connections and visual inspections.

 

[goodboy_pl]

as flatulent detecing neutral line with voltage monitoring is impossible but by current monitoring is POSSIBLE:
design a half wave recifier (with 3 diodes and a grounded capacitor) then use a resistor between output of recifier and the ground (neutral) and measure its current, if the current reaches zero then the neutral is open!

BEST!