How to build a clamp-on DC ammeter?

Discussion in 'The Projects Forum' started by Jack_K, Jun 28, 2013.

  1. Jack_K

    Thread Starter Active Member

    May 13, 2009
    I need to measure 50 - 60 amps of DC current. I realize a shunt resistor for a milliamp meter is probably not practical. I have seen clamp-on meters that can measure AC or DC current, but they're rather expensive.

    So, how can I make a clamp-on (or regular) meter to measure high DC current?
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    Hall effect sensor/ split iron core then the associated electronics to scale/present a proper calibrated value.. Its not a "simple" task as calibration/hall sensor placement,etc..can be tough for a DIY project.

    But personally I would simply buy a 50mv 100 Amp "shunt" and measure the voltage coming off it with your dc voltmeter. Something like this

    100A would be 50mv, 50A would be 25mv.. you can take it from there.
  3. GopherT

    AAC Fanatic!

    Nov 23, 2012
  4. Jack_K

    Thread Starter Active Member

    May 13, 2009
  5. Dodgydave

    Distinguished Member

    Jun 22, 2012
    What do you call expensive there are some on Ebay
  6. cork_ie


    Oct 8, 2011
    If you don't need good accuracy i.e.+/- 10% Blue Point used to make an ammeter suitable for the 50A range you are talking about.
    They had no electronics and solely relied on the deflection of a needle with a magnet attached which was attracted/repelled by the magnetic field generated by the current in the wire.
    Great little too still working almost 35 years later.
    You could easily enough make your own with a cheap magnetic compass and a lot of time to do the calibrations.