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Is true (RMS) really needed in a clamp meter ? #38804
06/02/04 08:49 AM
06/02/04 08:49 AM
L
leesops  Offline OP
Junior Member
Joined: May 2004
Posts: 4
Hi new here and was looking at some clamp meters some say true (RMS) others don't is it really needed.

Also what is the max AMP, I would need some go up to 400amp others 600amp to 1000amps.

Was looking at ( FLUKE, CRAFTSMAN, AMPROBE )

Thanks for any help I may get.

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Re: Is true (RMS) really needed in a clamp meter ? #38805
06/02/04 09:07 AM
06/02/04 09:07 AM
R
Ryan_J  Offline
Moderator
Joined: Aug 2003
Posts: 1,374
West Jordan, Utah, USA
RMS is definitley needed if you are measuring harmonic currents.


Ryan Jackson,
Salt Lake City
Re: Is true (RMS) really needed in a clamp meter ? #38806
06/02/04 12:27 PM
06/02/04 12:27 PM
N
nesparky  Offline
Member
Joined: Jun 2001
Posts: 642
omaha,ne
the max amp or size and cost of your meter depends on what you are measuring. If all the loads come from 100 amp circuit breakers or less, any of the ones you listed would work. if you are measuring 600 or 800 amp loads then you need the greater capacity.
Also true rms give you better accuracy but if you are only checking non plc controlled motors you do not really need it. For any load with harmonics you need that accuracy


ed
Re: Is true (RMS) really needed in a clamp meter ? #38807
06/02/04 12:38 PM
06/02/04 12:38 PM
R
Ryan_J  Offline
Moderator
Joined: Aug 2003
Posts: 1,374
West Jordan, Utah, USA
I used a Fluke 36 and was always very happy with it.


Ryan Jackson,
Salt Lake City
Re: Is true (RMS) really needed in a clamp meter ? #38808
06/04/04 12:22 AM
06/04/04 12:22 AM
L
leesops  Offline OP
Junior Member
Joined: May 2004
Posts: 4
Thanks for the help.

Re: Is true (RMS) really needed in a clamp meter ? #38809
06/06/04 06:42 PM
06/06/04 06:42 PM
Trumpy  Offline

Member
Joined: Jul 2002
Posts: 8,231
SI,New Zealand
leesops,
A non-True RMS meter can have an error factor of up to 30% on AC systems that include harmonic components in the sine wave.
Personally, I only use True RMS test gear for finding things like stray neutral currents and the like.
I see that APPA has just released a new series of True RMS Clampmeter/Voltmeters
And one of them, the A16R has a 1000A scale
this can be seen at http://www.appatech.com
Having the Cat IV 600V/Cat III 1000V rating's also helps.


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