How to sense DC current

[Mithun_K_Das]

How can I sense/Measure DC current of a line of 20A to 100A??

 

[moataz fouad]

Dear Mithun_K_Das,

There are many methods:
1. Non-isolated solution: using a small resistor (around 1mOhm) in series with the DC current path, most probably you will need a signal conditioning stage to get a reasonable voltage levels proportional to the measured current
2. Isolated solution: using a current transformer (for AC currents only) with a suitable ration, say 1:1000
3. Isolated solution: Using hall-effect sensors

Check the attached pdf for method 1.

Best regards.

 

[FvM]

A current transformer won't sense DC current.

 

[jpanhalt]

Here's a link to a Hall sensor that might work for you: **broken link removed**

If you want an simple, off-the-shelf solution, check out various hobby sites that cater to electric models (almost all sites do nowadays). Current monitors for DC are quite reasonably priced.

John

 

[moataz fouad]

A current transformer won't sense DC current.

absolutely correct

 

[sapna.dudani@gmail.com]

tutorial on isolated dc current sensing

http://www.analogzone.com/dearden_0731.pdf

related links

**broken link removed**
http://bbs.dianyuan.com/bbs/u/31/1122343862.pdf
Electric Current Measurement


one more good link.........
http://www.linear.com/ad/08-dc.pdf

 

[Mithun_K_Das]

I need to do in isolated way and also need to measure DC current so CT is not applicable for this case. As current is high(20-100A) so resistive loss may create power loss.

Anyway thanks for 01332A.pdf file. its very helpful.

 

[FvM]

I need to do in isolated way and also need to measure DC current.

Then all flavours of hall effect sensors shoudl be considered:
- closed magnetic circuit compensating sensors (highest precision)
- closed magnetic circuit direct measuring
- open magnetic circuit

 

[Mithun_K_Das]

Thank you everybody. I also recommend hall sensor. I found some helpful information from 'sapna.dudani@gmail.com', 'jpanhalt' & 'moataz foua' && Thank you all. It will depend on my local market. I think hall sensor will be reliable for this measurement.

But, can anyone tell me that what technique is used in DC Clump meters for DC current measurement?

 

[Raza]

Hi Mithun,
Another way, the easiest, is to use a DC CURRENT Clamp meter with a range up to 1000 Amperes.

 

[FvM]

But, can anyone tell me that what technique is used in DC Clump meters for DC current measurement?

As all contactless DC current sensors, a clamp meter uses hall sensors.