Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Current in twisted cable

  1. Jul 9, 2015 #1
    Hi guys !!
    Is there any way to detect current /generated magnetic field using hall effect sensor ss49 ?? or any other to just detect current in that cable ? please help me .
     
  2. jcsd
  3. Jul 9, 2015 #2

    nsaspook

    User Avatar
    Science Advisor

    We need information on exactly what you want to do to give a good answer. You would have to know the length, quality of the twisted pairs with the frequency and power level of the signal. In a detector system the SS49 has a sensitivity of 0.90mV/G but it's designed as an analog position switch so the frequency response of the internal amplifier might be limited.

    http://redshift.vif.com/JournalFiles/V16NO3PDF/V16N3CAL.pdf
     
  4. Jul 9, 2015 #3

    jim hardy

    User Avatar
    Science Advisor
    Gold Member
    2016 Award

    have you done any homework ?

    Seems to me Honeywell provides great applications help in their Hall Effect Sensing handbook

    http://sensing.honeywell.com/hallbook.pdf
     
    Last edited by a moderator: Jul 9, 2015
  5. Jul 9, 2015 #4

    berkeman

    User Avatar

    Staff: Mentor

  6. Jul 10, 2015 #5
    It is for detecting current flow in any appliance that is basically to know whether a device is ON or OFF.
     
    Last edited by a moderator: Jul 10, 2015
  7. Jul 10, 2015 #6
    by the current flow ,some magnetic field is induced .So by hall effect sensor I need to detect the current in the wire.
     
  8. Jul 10, 2015 #7

    Baluncore

    User Avatar
    Science Advisor

    Is the current AC or DC ? How many amps do you expect ?
    Do you need to know if on/off digital output ? or how many amps analogue ?
     
  9. Jul 10, 2015 #8
    It is AC with about 1- 5A .I just need to know on /off digital output
     
  10. Jul 10, 2015 #9
    Then, yes. There is a way.

    You need to get the datasheet. (Try Digikey.) Then you need to know the field strength produced by a wire. You will notice this is a small number. It is very small when compared to the curves on the data sheet. :oldcry:

    So either be prepared to spend thousands of dollars on top end electronics capable of measuring microvolts, or find another solution. (According to the datasheet the output varies with supply voltage, so any noise in the supply will affect your measurements.) Perhaps you can concentrate the magnetic field using ferrite or wire loops or both. Perhaps another sensor is in order? They make clamp on current meters using hall sensors, so I know it can be done.
     
  11. Jul 10, 2015 #10

    anorlunda

    Staff: Mentor

    An inexpensive DVM with a 10A current scale would do it if you can route the 1-5 amps through the meter.

    A clamp on amp meter can do it without breaking the circuit, if you can clamp one of the two conductors.
     
  12. Jul 10, 2015 #11

    Baluncore

    User Avatar
    Science Advisor

    If you pass both wires of the twisted pair through the clamp, but in opposite directions, you will double the sensitivity and eliminate any common mode signal. More turns about the clamp core = more sensitivity.

    Open the twisted pair either side of a half twist. Push the clamp prongs through the two holes in the cable and close it about the two wires which are now running in opposite directions so the currents sum.
     
  13. Jul 10, 2015 #12

    Averagesupernova

    User Avatar
    Science Advisor
    Gold Member

    There are LED indicators that are paired up with a current transformer just for such an application. My water heater uses them. As Baluncore has suggested run multiple turns through to get the desired result. For instance, get an indicator that is made to light up in a range of 15 to 20 amps. Pass the wire in question through enough times to get it operating when you want it. These devices often have a max current spec.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook