I have a 400V TN net and have bought 2 emonTx V3, is it possible to measure both one 3 phase and one single phase with each emonTx V3?
or do I need to also measure the N leader and then use all the channels on the emonTx V3?
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One 3 phase and one single?Submitted by eugen66 on Tue, 06/01/2015 - 11:21I have a 400V TN net and have bought 2 emonTx V3, is it possible to measure both one 3 phase and one single phase with each emonTx V3? or do I need to also measure the N leader and then use all the channels on the emonTx V3? » |
Re: One 3 phase and one single?
Each emonTx V3 has one voltage input and 4 current inputs. While the emonTx was designed for a single phase system such as we have in almost all domestic premises in the UK, it is possible, with the correct sketch, to get a good approximation to the real power on a 3-phase system using the 3 main current inputs with the one voltage input, which leaves a single current input free to use on any one remaining single-phase load.
The TN system is essentially a 4-wire system, therefore you only need to measure on 3 of the wires. This is usually the 3 line conductors, the neutral is not normally monitored. The exception to this is if you are looking at residual current protection or similar, and you need to remember that the emonTx is not designed as a protective device and it is not suitable to be used as such.
I hope that answers you, but I'm not certain that I understood your question correctly.
Re: One 3 phase and one single?
Thank you very much;) this was the answer I was looking for ;) do you also so know if there is such a sketch available?
Re: One 3 phase and one single?
Yes, in GitHub, if your emonTx V3.2 has the RFM12B radio (https://github.com/openenergymonitor/emonTxFirmware/tree/master/emonTxV3...), otherwise there is a version for the emonTx V3.4 with the RFM69CW radio at http://openenergymonitor.org/emon/sites/default/files/emonTxV3_4_3Phase_.... (I don't know why this hasn't made it into GitHub).