Author Topic: AC clamp meter something to look out for  (Read 3112 times)

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Offline BiOzZ

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AC clamp meter something to look out for
« on: April 11, 2013, 10:56:11 pm »
so earlier i had my cheap craftman 82372 clamp meter and i went to measure the PRIMARY side of a spot welding transformer i was working on and it jumped up to 85 AMPS ... i KNOW it was not putting out 85 amps on a 15A breaker even for just a second
i remember seeing on one of daves blogs that they use a some sort of hall effect sensor or wire loop so i took it aside and placed it on top of the tranny and turned it on and got 65amp than i put a magnet on the metal loop contact thing and got 8 amps (using the max hold setting) so it was either generating some sort of arbitrary magnetic field or voltage from the triboelectric effect giving a false reading ... granted i was never trained in any way for using clamp meters!

this might be very well known or not but i thought id put it out there incase it saves someone some heart ache!
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Offline NiHaoMike

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Re: AC clamp meter something to look out for
« Reply #1 on: April 12, 2013, 01:11:18 am »
Clamp meters are inherently sensitive to EMI. The better ones would have shielding and/or multiple Hall sensors to attenuate magnetic fields from outside the clamp.
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Offline opablo

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Re: AC clamp meter something to look out for
« Reply #2 on: April 12, 2013, 11:51:32 am »
A few days ago I bought my first clamp meter (Uni-T UT204 TrueRMS AC/DC) and I don't know what to think...
It's either broken.... or clamp meters are shit... Or I have certainly no idea how to use it in a proper/consistent/reliable way.
Or... it's unrealistic from me to pretend to use it for measurements with a better than 100mA accuracy.

I think that the most probable case is that I don't know how to use it properly...
Does anybody know of a video with all the tips around them ?
 

Offline peterthenovice

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Re: AC clamp meter something to look out for
« Reply #3 on: April 12, 2013, 12:14:01 pm »
A few days ago I bought my first clamp meter (Uni-T UT204 TrueRMS AC/DC) and I don't know what to think...
It's either broken.... or clamp meters are shit... Or I have certainly no idea how to use it in a proper/consistent/reliable way.
Or... it's unrealistic from me to pretend to use it for measurements with a better than 100mA accuracy.

I think that the most probable case is that I don't know how to use it properly...
Does anybody know of a video with all the tips around them ?

go search on yotube.
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Offline opablo

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Re: AC clamp meter something to look out for
« Reply #4 on: April 12, 2013, 12:25:12 pm »
go search on yotube.

I did... And I lost 5 hours of my life watching people selling bad clamp meters, not knowing how to use good clamp meters, doing incredible bad reviews of clamp meters, and talking about clamp meters with less knowledge than what I had prior to even touching one with my hands.

I hope that someone like Dave, Mike, Alan or Shahriar made a video about them.
 


Offline opablo

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Re: AC clamp meter something to look out for
« Reply #6 on: April 12, 2013, 11:01:48 pm »
Thanks for the great link Wytnucls.

After playing around with my UNI-T UT204,
And reading Wytnucls' review of the UNI-T UT204,
And reading BravoV's review of the Agilent U1213A,

I decided to sell this... thing... that I won't use much... and buy the GTC CM100
 


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