Poll

Are you interested in seeing more handheld meters tested?

This testing is pointless! Please STOP damaging these meters!
3 (6.4%)
 Yes, I would like to more meters tested.
44 (93.6%)

Total Members Voted: 47

Author Topic: Handheld meter electrical robustness testing.  (Read 530534 times)

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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2525 on: May 06, 2018, 05:15:44 pm »
There may be a part 2 to talk about the sensor's design.   Enjoy.

https://youtu.be/k8hhtTtWfVc
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline MacMeter

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Re: Handheld meter electrical robustness testing.
« Reply #2526 on: May 06, 2018, 11:58:59 pm »
Break down & repair, very detailed as usual. Great job Joe!
 

Online IanB

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Re: Handheld meter electrical robustness testing.
« Reply #2527 on: May 07, 2018, 01:20:09 am »
There may be a part 2 to talk about the sensor's design.   Enjoy.

That was remarkably accurate. It mostly got the voltage correct to ±1 volt with no direct contact. I'm impressed.
I'm not an EE--what am I doing here?
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2528 on: May 07, 2018, 02:56:23 am »
Even with me being fairly insulated I was amazed how well it works.   

I soldered some test points the to the board and started to poke around it.  They seem to use a 2.4KHz sinewave for their reference.  I have not done a lot of tests but it appears to always be running (while in the non-contact mode).   This make some sense as they need to actively measure the capacitance.   The capacitance from a wire to the sensor is in the 10s of pf.  Looks like maybe two plates, one with a lower capacitance.   

They must have to work with uninsulated wires as the area near the jaw is very thick.  Moving a wire inside the saw area with the cover removed, it is really sensitive.   

With the low freq. reference and working in the few megs of coupling, it may explain why the unit has troubles with high frequency signals.  I wonder if they would be better off making the final measurement with the reference disabled.  Talking out of my ass.  I really have no idea how it even works yet.... 


 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2529 on: May 09, 2018, 04:26:41 am »
Running the Fluke T6 on the half cycle line simulator.   


How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline tautech

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Re: Handheld meter electrical robustness testing.
« Reply #2530 on: May 10, 2018, 02:44:42 am »
With the low freq. reference and working in the few megs of coupling, it may explain why the unit has troubles with high frequency signals.  I wonder if they would be better off making the final measurement with the reference disabled.  Talking out of my ass.  I really have no idea how it even works yet....
As this is predominantly an electricians DMM I wonder how the non-contact feature work with motor speed control inverters ?
How does it sense approximate voltages and currents by comparison to a scope and current probe ?
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2531 on: May 10, 2018, 11:04:56 am »
As this is predominantly an electricians DMM I wonder how the non-contact feature work with motor speed control inverters ?
How does it sense approximate voltages and currents by comparison to a scope and current probe ?
I don't have any motors like this.   I could try it on the mains panel but the loads in the house are going to be fairly clean.

I've thought about taking one to a few places to try it just, for my own curiosity.

Using a scope would vary on the setup.   Probes could be picked to give a nice dynamic range.  You are locked in with this Fluke clamp.  There is no range selection.   With the scope, you may be able to over sample.  If you wanted, you may be able to also compensate for other limitations with a scope to get even better results.   Then again, I would assume if you are using this Fluke, you are an electrician and I doubt they would have the same requirements.   Hard to imaging an electrician taking a scope and current probes into the field.    I am not an electrician but if I have to go into the field I will take that HIOKI I have shown.  Two different tools with different price tags...

Using Labview with my old scope along with the breakout box I showed in the Fluke video.
https://youtu.be/04I7nHA_HxM?list=PLZSS2ajxhiQBcHhIaGpmm9GyZQfrCzqkv

   

How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2532 on: May 11, 2018, 01:12:42 am »
I tried a few different things with the meter today.   First test was on about a 5ish HP 220V 3P motor.  No problems.   I then tried it on a single phase 220V, phase controlled 30A load.  Again, no problems while controlling the current.   I then tried it with a small 220V 1.5KW 3 phase Omron controller and saw no problems.    In all cases I was trying it with and without grounding and it seems to do fairly good with my work boots on while standing on concrete.   

The biggest complaint I would have is having to bend the wires to get them into the jaw to make the measurements.  The systems I was working with had wires that liked to move. 

I showed a few people who were also impressed with how well it could read the non contact voltage.  I did get a comment once about working with my one hand on the equipment while probing around.  Good to know people still worry about me.

Again, I am not an electrician or work in a place where I would need to measure the AC mains but I could see something like this being handy under the right circumstances.   

***

Just to add, I forgot to mention that the Omron controller uses PWM and was surprised the T6 could read it.  I am not sure why it had so much trouble with some of the other waveforms I was testing with.    Attached is looking at one phase from this controller.



« Last Edit: May 11, 2018, 02:35:29 am by joeqsmith »
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline tautech

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Re: Handheld meter electrical robustness testing.
« Reply #2533 on: May 11, 2018, 05:07:27 am »

***

Just to add, I forgot to mention that the Omron controller uses PWM and was surprised the T6 could read it.  I am not sure why it had so much trouble with some of the other waveforms I was testing with.    Attached is looking at one phase from this controller.
Thanks Joe, exactly what I was wondering about.
Indeed measurement of modern systems control can be challenging and it's good to know the T6 can deliver at least the basics in this regard.
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2534 on: May 12, 2018, 01:58:18 am »
To me, it makes no sense that the T6 could handle the PWM from the Omron VFD and have problems with some of the waveforms I used with the ARB.   A few people had pointed out how when I started to move the wire with my finger that the T6 started to read the voltage.  Maybe there is something else going on there.   


How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline tautech

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Re: Handheld meter electrical robustness testing.
« Reply #2535 on: May 12, 2018, 02:40:37 am »
To me, it makes no sense that the T6 could handle the PWM from the Omron VFD and have problems with some of the waveforms I used with the ARB.   A few people had pointed out how when I started to move the wire with my finger that the T6 started to read the voltage.  Maybe there is something else going on there.
Surely it's just sensitivity related....real power levels vs little signal level stuff.
It is an electricians DMM not an electronic engineers meter, right ?

Horses for courses.  :)

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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2536 on: May 12, 2018, 03:44:39 am »
I am not sure what we would call sensitivity.  The T6 seems fairly sensitive to pure sinewaves at voltages ranging from 16 up to 440ish.   20Hz it was rolling off a bit but 50 to 400Hz seems to have little to no effect on how it detected the voltage.    Everything I tested it with at home was at less than an amp.   So I agree, it is little signal stuff.   

But a simple sinewave with a spike at the zero cross, which is a standard IEC waveform, that it has a problem with.  Even a 60Hz square wave causes problems at higher voltages.   Sure there is no load when I ran these tests and I am really only concerned with the non-contact voltage detection.   What I don't understand is why it has no problem with that Omron controller.  It's using a 15KHz carrier PWM signal.  I tried it at 50 to 60Hz. It's fairly square.  There is no load as well.  Just a wire hanging off the controller.    I was VERY surprised that it worked at all.     

The manual mentions both the safety and EMC standards.  I would have thought they would have ran all the basic harmonic tests.   

I am thinking to write some sort of  program to automate a much larger test where I very several parameters and try to get a better idea what is going on.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Online IanB

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Re: Handheld meter electrical robustness testing.
« Reply #2537 on: May 12, 2018, 03:54:41 am »
Some reviewers have said "this thing sucks, it doesn't work at all". You found that it sometimes works, but sometimes not.

I'd guess there is some factor "X" at play regarding the conditions in which it is used, maybe alignment of the wire under test or something?

A puzzle for sure. On the other hand, if a test instrument is not reliable, then how can it be trusted?
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2538 on: May 12, 2018, 04:54:37 am »
Some reviewers have said "this thing sucks, it doesn't work at all". You found that it sometimes works, but sometimes not.

I'd guess there is some factor "X" at play regarding the conditions in which it is used, maybe alignment of the wire under test or something?

A puzzle for sure. On the other hand, if a test instrument is not reliable, then how can it be trusted?

We have seen other instruments with design problems that were not discovered for several years, yet people trusted the results.   

Watching the video review, we see a Klein Tools, PN#  69409 splitter being used to attempt to make the measurement.  Looking at the quick reference, the first thing it the overview,  they talk about 1 wire only and the wire must contact the bottom of the fork.   There are also pictures that make it easy to understand.   Of course, in this case an understanding of the splitter was required as well.    We really have no way of knowing the specifics of people providing feedback.  The best I can offer is to just show you the tests I have ran. 
 
When I took the T6 with me for the day, I didn't have any problems if I could get to the wire I wanted to measure.   However, all of those signals I would say were common and clean.   

If I were trying to make these sort of measurements often, as say some sort of process control,  I can see it saving time and being safer to use.   Would I use it to make basic voltage measurements and trust the results, based on my experience with it, I would say in many cases, yes.   

When I run my own tests, I am looking for problems.  This is why I use an arb rather than a wall socket to test the meters.  Obviously, I discovered cases where it can't detect the voltage depending on the shape of the signal.   This is really what interests me. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline tautech

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Re: Handheld meter electrical robustness testing.
« Reply #2539 on: May 12, 2018, 05:27:12 am »
First one need understand the MO of an electrician when he needs to pull out a meter. Typically not everyday.

What the measurement requirement is determines whether they reach for Duspol or a DMM.
Is voltage present, is it real or phantom ? (LowZ test)

Controls systems: 12, 24 or 48V AC or DC and not much else.
Power systems (universally) 110/120, 230/240, 400/440 VAC. 1% accuracy is all that's generally required.
Current.....mainly to fault find the reason why breakers are tripping, checking AC motors are running within spec and checking circuit's aren't overloaded.
Continuity, checking HRC fuses and similar menial tasks.

Not exactly demanding work for a DMM but it needs be reliable, repeatable, trustworthy.....and safe.


So where might a T6 shine ?
My buddy was called into an industrial installation where a big AC motor kept tripping its breaker. As breakers don't like ongoing tripping events due to bi-metal degrading that was the first thing replaced......still tripped, motor rated breaker and all. Test phase current draw and how it compared to motor label spec.....well over.
Open frame motor and in a dusty environment.....10 minutes with high pressure air and tripping problem fixed.

Yep and you could have diagnosed it with any cheap clamp meter too but if you turn up on a job with a Fluke, those in the know immediately respect your ability to know what you're about.

The T6 is not an EE's meter, period.
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2540 on: May 12, 2018, 12:26:08 pm »
Hard for me to say what the use cases would be for this meter.  I wouldn't say a EE would never have a use for the T6 but it is not a tool I would ever use on a bench.  I personally could see non-electricians using the T6 in certain cases.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Online Fungus

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Re: Handheld meter electrical robustness testing.
« Reply #2541 on: May 12, 2018, 06:56:46 pm »
Hard for me to say what the use cases would be for this meter.  I wouldn't say a EE would never have a use for the T6 but it is not a tool I would ever use on a bench.  I personally could see non-electricians using the T6 in certain cases.

Everybody's freaking out about how if you'll die if you touch the metal stuff but it's obvious Fluke would have thought of that on day zero.

The main problem I see with it is that you need a lot of space around a wire to be able to take a reading. That really limits where you can actually use it IMHO.
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2542 on: May 12, 2018, 09:03:39 pm »
Hard for me to say what the use cases would be for this meter.  I wouldn't say a EE would never have a use for the T6 but it is not a tool I would ever use on a bench.  I personally could see non-electricians using the T6 in certain cases.
Everybody's freaking out about how if you'll die if you touch the metal stuff but it's obvious Fluke would have thought of that on day zero.

Are they still?

Quote
The main problem I see with it is that you need a lot of space around a wire to be able to take a reading. That really limits where you can actually use it IMHO.

Have you tried to use it?   

I'm setting up a more comprehensive waveform test.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2543 on: May 13, 2018, 03:56:23 am »
Checking the T6 with various waveforms.   IMO, this is a much bigger problem than the leakage current through the button.  Looks like they need to invest in something like this:
http://www.programmablepower.com/test-compliance/index.htm


https://youtu.be/JeX87PklmEU
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2544 on: May 18, 2018, 01:00:02 am »
Following Dave's technique, Voltlog tried using an insulation tester on a few handheld meters.   He quickly discovered that while in the resistance mode, the loading was just too much and he could only get a few volts. 

I wonder what would happen if we put 1KV DC across a cheap meter when it was in resistance mode.  It's not something I have ever tried.   

How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2545 on: May 20, 2018, 12:33:58 am »
In order to repeat VoltLog's test the Joe Smith way, we can't use a handheld insulation tester as a source.   

Note, if your have a 1KV supply and your using your meter to measure the current from it and the 440mA fuse blows, the first thing you need to be aware of is you now have 1KV across your meter's current inputs.   And you guys wonder why I test this these things.     The second thing to note is working with 1KV at 440mA  could end your life.  A GFCI will trip in well under 10mA in 100ms or so.    Here we are playing with DC. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Online IanB

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Re: Handheld meter electrical robustness testing.
« Reply #2546 on: May 20, 2018, 01:59:29 am »
This is when you start to wish meters didn't use $10 fuses...
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2547 on: May 20, 2018, 06:00:05 am »
The fuse cost more than the meter that caused it to blow.    Not sure how a half amp 240VAC glass fuse would like the 1KV DC.  Also not sure how many low end meters would survive with 1KV across their current inputs. 

https://youtu.be/HkdJ66vetWg

How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2548 on: May 26, 2018, 09:50:18 pm »
Just a quick update on the T6.   I received this comment a while back:

Quote
The other problem with the non-contact voltage measurement of the T6, is that it is referencing to earth. When ever I am fault finding in a panel, I am testing phase to phase or phase to neutral as that is the working circuit. Testing phase to earth is poor measuring technique, and is predominantly done when testing of absence of voltage, which the T6 is unsuitable for.

It made no sense to me that the meter would not work using the non-contact mode when reference to something other than the earth ground.   So I tried it on a few 3P circuits using a one phase for a reference and the non-contact on the others and as expected, saw no problem at all using it this way.   Obviously you would have to have failed your studies if you were to touch the button and grab a live phase with your other hand.   I am using the black reference probe when doing these tests.

I also had access to another Mitsubishi VFD that I tried it on.   The VFD was running a motor.   No matter what I tried, I could not get the T6 to read the voltage.  This controller was running with a carrier at 5KHz.  The VFD was reprogrammed to 15KHz and the T6 worked fine.   We tried a few other lower frequencies and was unable to get the T6 to read. 

All of the testing I had done up till now with VFDs was at higher frequencies.  Leakage current may be a problem and I would assume many controllers will run low carriers.  My guess is the T6's non-contact feature will have problems with this. 

How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2549 on: June 09, 2018, 08:27:53 pm »
Effects of 1KV on PCB rotary switch.

https://youtu.be/6j8i3LfKm5A
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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