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

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.

Thanks guys! I'll look into it.

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.