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The maximum current is nothing to do with the emonTx, it is a property of your current transformer. The "standard" YHDC c.t. is rated to 100 A so if that is what you want to use, there is no problem. Voltage does not come in to the picture.

Note that you must use 3 emonTx's for precise 3 phase measurements, or if you are content with an approximation, you must use one of the three-phase sketches. How good the approximation is will depend on how accurately the voltages of your three phases are balanced.

Thanks Robert!!!

I'm intrigued that you say ... then .. Is EmonTx for reading one CT 2000A? I understand that something must regulate this intensity, as is done with a clamp...

Certainly I need to work with high precision, but we work on site, it is normal that voltage is balanced, not the amperage, because the power of the equipment you load on each of the phases.

Think you then convenient to use 3 emonTx for 3 phase control? the truth is that with great facilities the problem is that you need a lot of equipment, and if you comment me besides that, the number of units EmonTx can be really important ...
Someone is doing work industrial monitoring with EmonTx?

If you use a 2000 A : 50 mA current transformer, you can indeed measure to 2kA.

I believe a number of firms are using the emonTx on their industrial plant. Martin Roberts made a very nice assembly of three stacked emonTx V2, here: http://openenergymonitor.org/emon/node/1170 and another of our menbers has done a 3-phase front end: http://openenergymonitor.org/emon/node/2674. You might be interested in both of these.

Thanks Robert!!!

I just get to read these post now

I have seen the post referred to, and are very interesting, although designed for PV ... the fact is that I had thought was to connect three FlexCT (Flexible Rogowski coil current sensors) to emontTx-V3 for logging. Someone used these sensors with emonTx? if so, can you say me where I can buy them?

Thanks again

As far as I know, nobody has used a Rogowski coil with an emonTx. Of course, you will need an integrator/amplifier to condition the output, and it will be necessary to modify the input circuitry of the emonTx to suit the output from the integrator.  When you have removed the input bias circuitry and the burden resistor, the amplifier should give an alternating voltage which is an exact copy of the current wave, of approximately 1.1 V rms at the maximum current you wish to measure, and biased to the midpoint of the supply (1.65 V). Although the performance of the emonTx V3 is an improvement over the V2, you may find it easier to modify and build an emonTx V2 rather than modifying an emonTx V3.

There are many suppliers of Rogowski coils who will also be able to supply the required integrator/amplifier.

Hello again everyone.

Robert, I have read and studied about what you were explaining me. I found a Rogowski sensor that can work with Vout of 40mV / kA and other 100mV/kA.  I understand that I must put a resistor and integrator/amplifier, but as I am no electronics engineer I can not know how it can be integrated into the EmonTx scheme to work. Can You have Might help? thanks in advance.

I thought I had already covered that in my previous post. You will probably need to buy the integrator/amplifier combination from the supplier of your Rogowski Coil. When you have decided on that, and have the full details, it should be possible to determine how to interface it to the emonTx.