Safely monitor 300v 10A current

Analog Optocoupler ....


Some form of cal will be needed.

Or a digital coupler solution with a processor on source side, possibly it gens a pwm
that can be filtered on observer side to recover DC value proportional to pulse width,
the pulse width proportional to micro RMS or peak measurement.


Regards, Dana.

Dear Dana, I', afraid your experetise exceeds mine and I have not really understood your proposal. I have tried to draw what I envisiage (I hope the link to my crappy photo works or please ask for it another way)./ I understand everything needed - the toroidial is fully isolated so either secondary may be connected to zero vots and the other used to ADC input. I halved the voltage just on general principal and besides one resistor can be made variable giving me exactly the voltage I want.
Actually, T! is supposed to go on the other side of the conditioner - I want to measure the improvement - but there is an argument for collecting both sides to compare. My wallet may not permit this though. Still, the 'good' side is better then the bad side.
Because the secondaries of T1 are isolated either may be connected to VDD and the other to the ADC input. The voltagle may be fiddled with and since the current is so low I don't think I need concern myself. An ADC should not really draw current anyway but there's plently more resistors if needed to rewduce it.

This bit is clear bto me. Next wew have the mysterious component X which is supposed to take the mini voltagle (1ohm at 300v at 4kv worst is still not going to produce much voltage differential. S1 may get a little warm though. Map havew to rethink the 1ohm part. My problem, anyway.

What I can't get my head around is both ends of s1 will be at 300v (I gave up writing 250cRMS. The night is old). And I do not want 300v anywhere NEAR my digital loggger. I don't think another transformer wouild work - 1mv at 1ma will just vanish unless I make the primary the shunt in which case I have just scuppered the whole point; there will be no power left for my poor load!

I need something that I can tie one end on to VDD without, er, exothermic disassembly and the other must have a sensible voltage differential of 3-5v. Aslo without the 300v part.

I can, of course use a bunch of resistors to step the voltage down ie 300v -> 100k > vout -> VDD and the same at the other side of s1 but my maths is too rusty to do more that intuit that thgis is a) dangerous and b) not likely to be both safe and produce much more than 0v at 0ma by way of output.

I need your superiour intelligence badly!



ps: The system (minus monitoring and shunt etc) is running now seeimingly without problems so I assume my 4kva was a wild overestimate. Of course, the PC states it's drawing 30W (CPU) and all drives are low current SSD/NVMes, only the graphics card is hungry and reports a TDP of 320W but I am typing this, not playing graphics intensive games but even so I think we can estimate 500W all in. I do have a 14Tb NASS but that's also all ssd and I guess uses around 10w.

Thanks for your time;
Jeremy