amp meter calibration

Discussion in 'General Electronics Chat' started by rodbolt100, Feb 2, 2012.

  1. rodbolt100

    Thread Starter New Member

    Feb 1, 2012
    2
    0
    Hello,
    I bought a 3 1/2 digital panel dc amp meter with shunt. It is a 200 amp. Unknowing to me at the time i bought the instructions say to hook up a 200 amp load to it and then adjust a small potentimeter until the display reads 200 amp. My question is how do i calbrate it when i dont have a known 200 amp load. I bought the meter to use on a hygrogen generator i plan to use on my car. The amp meter is used to adjust the concentration of electrolite. The target amp load is 16 amps. I should have done more research because i dont need to measure any current over 50 amp. I should have got a 50 amp meter instead. Also i guess i need an isolated power source, cant use the same power source to power the meter that i want to measure current. Can I used a known value of a resister as a load to calibrate, and how can i isolate the power. I dont have alot of electronics experience . Thank you in advance. Forgot to mention meter came with a 200 amp 75mv shunt thanks
     
  2. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    the meter will have a movement based on a small current, which should be stated on the meter. You'd recalc your shunt for a more manageable current.
     
  3. rodbolt100

    Thread Starter New Member

    Feb 1, 2012
    2
    0
    so i dont have to calibrate it because of the low current i want to measure?
     
  4. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    up to you if you want to calibrate it. Your shunt is typically a multiplier. What is your meter movement current rating?
     
  5. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,770
    970
    no matter what it would need to be calibrated.. What he was saying is that you could calibrate it at a lower value and hope the sensitivity is perfectly linear (in that calibration at 20 Amps "should" be the same as 200 Amps.)
     
  6. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    Most of the digital panel meters I've worked with have a basic range of 0.2volts (200mv). The shunt you have, if it follows what I've seen, will develop 200mv with 200amps flowing through it. Hydrogen Generation (over unity power) and Automobiles are two taboo subjects on this forum so this thread will probably be closed. Check the Terms of Service for further explanation.
     
  7. DickCappels

    Moderator

    Aug 21, 2008
    2,651
    632
    It should be good enough to calibrate this at your maximum working current. If the zero is set properly it should be accurate from zero to you maximum working current.
     
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