non invasive DC current sensor for arduino

Other Hardware General Electronics
1

Hello,

I would like to make some readings of the DC current from an existing wire. The current to be read will be something within the range -50A to +50A.

The best solution for my project will be to use a non-invasive DC current sensor although I am having some troubles to find an affordable one and also to understand the specification of the ones I have found to really know if I could use them (I am far to be an electronic expert).

I would appreciate if someone could recommend any non-invasive DC current sensor that suits my needs or if anyone could share similar experiences.

About the sensors I have found:

http://www.yhdc.us/ENpdf/HK(S)2010-50A-4V(2.5±0.625V)_en.pdf

According to the information “VOUT Rated output 4V(2.5±0.625V)”  Does it means that:

  • There will be 2.5v when no current thought the cable?
  • Does the out output will be 1.875v (2.5- 0.625) for -150A thought the cable and 3.125v (2.5 +0.625) for +150A?
    This will make 4.17mv/A which seems to low value…..
2

I could not read you link but looking at the part number I would guess the range is +/- 50A hall sensor. But again I could not connect to your link

From other hall sensors I believe your interpretation is correct.

Sensitivity = 0.625 / 50 = 12.5 mv/a does seem low.

The ACS758LCB-050B-PFF-T has a sensitivity of 40 mv/a. It is not technically non intrusive. But it is isolated and with the only drop being the solder connections and a small amount of board clad.

I'm sure there are others that use coils and do not break the wire. Look at ebay offerings.

You should be aware that hall sensors are stable for sensitivity but have a significant zero drift. You will find for an accurate reading you must periodically read the ~2.5 V when there is known to be no current and compensate for changes.

UPDATE:

If you find a non-contact sensor that is rated for 100A or 150A you can easily use it by running your wire through the center 2 or 3 times. The will increase the sensitivity by a factor of the number of times the wire goes through the sensor. Do not wrap it tight around the sensor, this will result in a sensitivity error.

3

The data sheet describes two different types of sensors, one that runs on +/- 15V (which also has a gain and zero adjustment) and another that runs on +5V, with no adjustments.

Presumably those figures give the output voltages for the two models at 50A input.

4

JohnRob wrote (in part):

I'm sure there are others that use coils and do not break the wire. Look at ebay offerings.

irrintxi wants "...to make some readings of the DC current". Coils will use AC current and will not work with DC current. Something non-intrusive (like a Hall effect device) or intrusive (like a current sensor or a current sense resistor) will be needed.

5

Coils will use AC current and will not work with DC current.

You are correct, my bad. I should have been more explicit.

I was referring to closed loop hall sensors which use a core but no traditional secondary windings.