Hello,
I just finish to install my 3phases setup, so I have a 3phases EmonVS, an emonTX4 and a emonPI.
The system seams working fine, I upgrade TX4 with the latest version, and configure the CT with what I have
3 100A for the main house supply, and 3 50A for some line.
But even that it’s not a 3phases code on any product, not yet available. how can I solve the issue of having some measure in minus instead of positive measurement.
You cannot. Whatever you do, the numbers for phases 2 & 3 (those NOT being measured by you single-phase code) will be wrong - because although your emonVs has access to the 3 voltages, the version of emonLibCM that you have cannot measure the other two voltages.
For a VERY approximate correction, multiply everything from phases 2 & 3 by -2.0 This will be a reasonable approximation for purely resistive loads, badly wrong if the power factor is not close to unity. (Look at a phasor diagram of the 3 phase voltages for your explanation - the other two projected onto the phase 1 axis are opposite (negative) and half the length of the phase 1 phasor.)
Remember to put everything as it was when the new library arrives. The good news is, it should not be long now.
This is for you to determine from the wiring colours or numbers.
If you have a standard 3-phase, 4-wire system, then as long as you assign the current’power channels to the correct voltage, you will read the power & energy correctly. Unlike the emonTx V3 “approximate” 3-phase sketch, phase rotation does not matter, it treats each pair of current and voltage as a single phase.
Therefore, you must still know the phase of each circuit you are measuring, so that you can allocate the correct voltage to it.
Ok I understand the part of the association of the CT with the phase I know which is where. But that will come with the 3phase version of the TX4 software right ?
Because for now I can’t find where it’s suppose to be.
If it’s any help, I sent Trystan what I think is a working version an hour or so ago. I need him to check it on a real 3-phase supply before releasing it.
I don’t understand what you mean. The version of emonLib that I think you are using simply does not read the 2nd & 3rd voltages. It needs a very different library (internally) to do what you need.
I have no news, I don’t know whether or how far he’s got with testing it. I live in an ordinary UK house, with only a single phase 240 V supply. I understand the Megni workshop has a 3-phase 240/415 V supply, and he has done some initial tests.
