Detection of phase availability in delta 3 phase system

[ocsee]

I need your help regarding Three phase(delta connection) detection ckt with optocoupler.

I want to sense phase is available or not.

Just like attached ckt.

So question is,
Attached ckt will work for 440v phase to phase?

 

[chuckey]

I am extremely unhappy with this circuit. If only one phase is active, then only one opto is on and only one transistor, but with your component values, the output will be a '0'. Well actually a '.5' because of the 1k emitter resistor. I would try putting all three transistors in series, no emitter resistor and proportion Rc so that with all three phases present, the Vc of the 'top' transistor is .6V (3 X Vsat). Then if a phase goes missing, the voltage at this point will rise. I do not think your series resistors are high enough in value, I feel 1M would be safer.
Frank

 

[ocsee]

Thanks for reply,

I am just interested for i/p connection of three phase for detection.

O/p ckt and Resistor values are different.

So, please tell me is it work?