Three Phase 240V AC energy monitor

Hardware emonPi
,
1

I am new to the emonPi product. I have a energy monitor requirement and wondering if I can use the emonPI for my use case.

Can emonPI monitor and collect data for a Three Phase (three wire) 240V AC circuit?
If Yes, how and what the hook up look like for Three Phase circuit look like?

Much appreciate for your suggestion, advice and comments.

Thanks,
Yoom

2

Yes - because you treat one of the phases as a neutral. Unfortunately, there is no sketch for the emonPi that will work correctly in your case.

I will reply more fully later.

[Edit]
The problem you have with the emonPi is it was designed for the UK single phase mains supply. The second problem is, if you update the emonPi software, any custom sketch that you have written to the “emon” part of the emonPi will be overwritten by the new default sketch. There is a way to avoid this happening, but you must remember never to update the emonPi as an emonPi, but treat it as an emonBase.
The third problem is, there is not a version of the latest 3-phase sketch for a 3-wire supply and for the emonPi.

So I think your options are:

  • Convert the existing sketch in the ‘emon’ part of the emonPi to read apparent power instead of real power. The values will be as good as many commercial units, but you will not read the true real power.

Or

  • Use an emonTx with an emonBase (effectively an emonPi without the case and without analogue voltage and current inputs), and use a version of the three-phase sketch with a small modification to suit your 3-wire system, in which you will actually treat one phase as the neutral and it becomes a two-phase system (with the second phase lagging 60° behind the first).

Or

  • Write a sketch for the emonPi to do what you need. This might not be practical (it might be impossible to make it work) because of the additional load on the Atmel 328P in handling messages received by radio, and handling the push-button and the LCD display.
4

Thank you. I like your suggestion below. use a version of the three-phase sketch??
Where do I find this three-phase sketch?

<<* Use an emonTx with an emonBase (effectively an emonPi without the case and without analogue voltage and current inputs), and use a version of the three-phase sketch with a small modification to suit your 3-wire system, in which you will actually treat one phase as the neutral and it becomes a two-phase system (with the second phase lagging 60° behind the first).

5

I need to make some changes to the one for a 4-wire system that I published here about 3 weeks ago.

That will take a few days, and I will publish it here.

I have no personal knowledge of the workings, capabilities or performance of Iotawatt (the greyed-out post by Overeasy above - I understand it is greyed-out due to a glitch in the forum software), so my professional code of conduct does not allow me to express an opinion or recommendation for that item.

6

Here is version 1.4.
It can be set for both 3-wire (as you have) or 4-wire systems, the default settings are for 4-wire, therefore you will need to change some of the settings. All the documentation is in the pdf file.

MD5 Hashes:

emonTx_3Phase_PLL_V1.4.zip	        f6f0fd4e57290ed985f23596e1f55bc0
emonTx_3Phase_PLL.ino	            c8e684a2549cde41629f2db205794b45
config.ino                          ae9cc9c91f67ed3a6b47e49cc1f47b32
rfm.ino                             44a0b048b14e5e013625809736853c57
emonTx 3-phase PLL User Doc.pdf:	c18387136424b903cdf49366f30fde9b

Extract the directory “emonTx_3Phase_PLL” and put it in your “sketches” folder. You can put the documentation where you wish.

emonTx_3Phase_PLL_V1.4.zip (151.9 KB)

I do not have a 3-phase supply, so I cannot test the sketch working. However, it does give the expected results on a single phase supply, so I believe it will work correctly.

[@Yoom Please read the PM I sent you a few days ago.]