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#38804 - 06/02/04 06:49 AM Is true (RMS) really needed in a clamp meter ?
leesops Offline
Junior Member

Registered: 05/31/04
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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#38805 - 06/02/04 07:07 AM Re: Is true (RMS) really needed in a clamp meter ?
Ryan_J Offline
Moderator

Registered: 08/19/03
Posts: 1355
Loc: West Jordan, Utah, USA
RMS is definitley needed if you are measuring harmonic currents.
_________________________
Ryan Jackson,
Salt Lake City

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#38806 - 06/02/04 10:27 AM Re: Is true (RMS) really needed in a clamp meter ?
nesparky Offline
Member

Registered: 06/21/01
Posts: 650
Loc: 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
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ed

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#38807 - 06/02/04 10:38 AM Re: Is true (RMS) really needed in a clamp meter ?
Ryan_J Offline
Moderator

Registered: 08/19/03
Posts: 1355
Loc: West Jordan, Utah, USA
I used a Fluke 36 and was always very happy with it.
_________________________
Ryan Jackson,
Salt Lake City

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#38808 - 06/03/04 10:22 PM Re: Is true (RMS) really needed in a clamp meter ?
leesops Offline
Junior Member

Registered: 05/31/04
Posts: 4
Thanks for the help.

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

Member

Registered: 07/05/02
Posts: 8540
Loc: 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.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

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