A question regarding Current Transformers and their measurement capabilties please.
If I have 1 x Current Transformer clamped around one phase/active wire this will measure the AC current and direction of current for that one wire. I understand this.
If the Current Transformer is clamped around 2 x phase/active wires with current flowing in the same direction, will it measure current twice? wire 1 + wire 2
The context of my question is I have 2 x 240 volt AC feeds from solar panel arrays. to conserve use of EmonTX Current Transformer inputs, can I use 1 x Current Transformer clamped around both feeds? Will this measure the current from both feeds agregated? Or will it only measure the current once?
Do I need to use 2 x Current Transformers. one for each feed? or can I use one Current Transformer to measure both feeds at the same time and log to a sinlge EmonCMS input.
The CT will indeed measure the current value, but to determine the direction, you also need a voltage reference.
If the wires belong to different single phase circuits, i.e. they are not simply in parallel, then yes, the CT will yield the sum of the currents. If the wires belong to two phases of a 3-phase circuit, the CT will yield a vector sum.
If memory serves, you uploaded a diagram of your system, showing the feeds from your PV arrays.
If your PV system is single phase, yes, you can clip the CT around the same leg of both PV feeds to get an aggregate sum. (If opposite legs are run through the same CT, the resulting measurement will be zero.)
If a point exists where both conductors are joined prior to the infeed, i.e. one wire, vice two, you could attach the CT there.
One CT will do the job, but if you want to, you can use two CTs.
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Thanks Bill.
I greatly appreciate the concise responses.
I understand everything now and I think all my planning is done. I just need the Pi and TX to arrive (hopefully this week) so I can get the units installed.