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Topic Title: Fluke T6
Topic Summary: How can this work??
Created On: 02 October 2017 06:23 PM
Status: Read Only
Linear : Threading : Single : Branch
 Fluke T6   - Electutor - 02 October 2017 06:23 PM  
 Fluke T6   - geoffsd - 02 October 2017 06:58 PM  
 Fluke T6   - dp11 - 02 October 2017 07:01 PM  
 Fluke T6   - Electutor - 02 October 2017 07:30 PM  
 Fluke T6   - geoffsd - 02 October 2017 07:35 PM  
 Fluke T6   - rocknroll - 02 October 2017 07:57 PM  
 Fluke T6   - geoffsd - 02 October 2017 08:04 PM  
 Fluke T6   - leckie - 02 October 2017 09:09 PM  
 Fluke T6   - AJJewsbury - 03 October 2017 08:59 AM  
 Fluke T6   - mapj1 - 03 October 2017 10:44 AM  
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 02 October 2017 06:23 PM
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Electutor

Posts: 37
Joined: 24 October 2016

Has any one seen the new Fluke T6 open jaw? The question I have is that the manufactures claim you can accurately measure Voltage simply by using the tongs. I have no idea how this is possiable. Any one know the principles of operation? I under stand how current is measured but the idea of measuring voltage at one point in the circuit is beyond me. Let alone how this can be achieved by the use of an open jaw clamp.
 02 October 2017 06:58 PM
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geoffsd

Posts: 1787
Joined: 15 June 2010

It doesn't.

Where have you seen that claimed?
 02 October 2017 07:01 PM
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dp11

Posts: 97
Joined: 18 June 2011

says it here : http://en-us.fluke.com/product...lectrical-tester.html

small print is helpful
 02 October 2017 07:30 PM
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Electutor

Posts: 37
Joined: 24 October 2016

The claim is made in this YouTube video https://youtu.be/JkHJR8RYKps. Thanks just read the small print. Seems a bit disingenuous as will only measure value to earth and no use on isolation transformes ect.
 02 October 2017 07:35 PM
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geoffsd

Posts: 1787
Joined: 15 June 2010

Ah. My mistake.
I was looking at the T5 which appears on the same document.
http://www.fluke-direct.com/pd...t6-1000-datasheet.pdf

The T6 has "field sense technology" but doesn't say how it works.
 02 October 2017 07:57 PM
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rocknroll

Posts: 9550
Joined: 03 October 2005

Originally posted by: geoffsd

Ah. My mistake.

I was looking at the T5 which appears on the same document.

http://www.fluke-direct.com/pd...0-datasheet.pdf



The T6 has "field sense technology" but doesn't say how it works.


'Field sense technology' has been around for a bit mainly in the VR world but has been developed for many applications now thanks I suspect to the Chinese who have probably made it affordable, the basic principle is you inject a known signal or pulse into something and then you get information back, generally very accurate to within a few microns.

Regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------
 02 October 2017 08:04 PM
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geoffsd

Posts: 1787
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 02 October 2017 09:09 PM
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leckie

Posts: 4455
Joined: 21 November 2008

So the clamp device for testing electrodes that I have is a similar thing from the sounds of it. It injects a current through the loop between two electrodes I think and turns this into a measure of resistance. This does it with voltage from the sounds of it.

However, this does it with an open fork. Sounds very useful. I bet JP has one on order.
 03 October 2017 08:59 AM
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AJJewsbury

Posts: 16120
Joined: 13 August 2003

I've got two theories - either it uses the user's body as an earth reference (like a volt stick or the old neon screwdriver), or given that Fluke's wording is "without test lead contact to live voltage" you'll still need a single test lead to make a reference earth connection (the video, curiously, doesn't show the lower end of the meter where the leads would connect).
- Andy.
 03 October 2017 10:44 AM
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mapj1

Posts: 9717
Joined: 22 July 2004

Well you can look at the Fluke Webpage, and it more or less tells you in a footnote.
Measure voltage ... without test leads

FieldSense technology lets you slide the open fork over a conductor and see the voltage level.1

Be safer: Measure voltage to 1000 V ac through the open fork, without test leads...
<<blah blah>>
..Measure voltage up to 1000 V ac through the open fork, without test lead contact to live voltage.+
It will change your job...
<<snip>>
...
1 Requires capacitive path to ground, provided through user in most applications. Ground connection via test lead may be required in some situations


So it's just a high impedance meter, so high that the capacitance effect is is dominant, it is effectively a low frequency "d-dot" probe, as they are called in the world of pulse power.

('d-dot' being a spoken word for D' , a maths/physics shorthand for

'rate of change of the quantity representing the Displacement of charges from their relaxed position, associated with an electric field'

- So think of it as the 'tension' in the dielectric of a capacitor when the positive and negative ends of molecules get pulled about a bit, like something between aligning an array of compass needles or pulling curly spaghetti straight. When you reconnect the ends of the capacitor you get your stored elastic energy back... sometimes with a bang if you do it too fast. )

Anyhow, I suspect like all field sensors it can be fooled in certain situations.
I'd not want to rely on one where I work as anything more accurate than as a 'maybe live' indicator, without a lot of testing.

An example of the same D-dot idea in another context, for more general use.

-------------------------
regards Mike


Edited: 03 October 2017 at 11:02 AM by mapj1
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