Advice on measuring current on one phase of 380V 3-Phase

Hi all,

I have done a project or two but am still very new to Arduino and IOT. I am trying to support an improvement drive at a client and for this I need to be able to measure the current on his three phase (380V) machines and send that data every minute or so to a database.

My main concern for now is to find the right type of inductive sensor to interface with an Arduino. One that can handle high currents (100A +) and which are preferably non-invasive (inductive).

Some of the industrial ones don't work on the 0-5V output for an Arduino's analogue reading. Are there good 0-5V output inductive current sensors out there? And alternatively, which ones are typically industry standard and what shields do I need to work with them?

Thanks in advance
Gerhard

You could try something like this:

configure it for 0-100A, 0-5V output and 12Vdc power. The only drawback I can see is that it doesn't appear to be a split-loop so you'd have to disconnect the phase at one end, pass it through the sensor and then reconnect it.

If you're measuring 100A with 10-bits you're only going to get about 100mA granularity in the readings: Is that sufficient for your needs?

You can use one of these split core current sensor
The documentation is poor but the output seems to be 0 to 1 V for 0 to full current.

However the output will be AC not DC so you either take a lot of reading looking for the peak (which may not be the best measurement since power waveforms are not a perfect sine) or use a simple opamp to rectify half the waveform and average the result.

IMPORTANT: you need to be sure the AC sensor opening is large enough to fit the wire on your target device.

Also 380 VAC at 100 Amps is a lot of power. You might want to recheck that 100Amp number.

For an "industrial" solution all current transformers work the same way. They act as a transformer with a:
1 turn primary
1000 + turn secondary.

The output of the secondary is loaded with a resistor (called burden resistor) that results in a voltage output of something line 0 to 1V. Googling them will result in numerous options.

Also look here.