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 robustness testing  (Read 651759 times)

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Offline stj

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Re: Handheld meter electrical robustness testing.
« Reply #2725 on: August 19, 2018, 11:10:10 am »
i hate yellow equipment, it makes it look like i robbed the back of a telephone-company van!!!
in the u.k. the state phone company has had all it's test gear made in yellow for about 50 years!
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2726 on: August 19, 2018, 12:23:08 pm »
Time to break out a C-note.  Bidders could almost buy one of Dave's rebranded Brymen BM235.  They must really want to save this old 189 from total destruction.   :-DD
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2727 on: August 19, 2018, 01:44:48 pm »
Maybe they want to scavange parts to a another one :p or are very skilled repaired people.

The brymen BM235 is way better than the uni-t 61b, even it has less resolution. I believe someone sugested a rotary swiych 50k cycle to this brymen.
If one can make knowledge flow than it will go from negative to positve , for real
 

Online rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2728 on: August 19, 2018, 02:03:00 pm »
Unless the seller shared an internal picture of the meter and it looks fine, I suspect the bidders may be unalerted of the potential pitfalls. I wonder if we will soon see a thread here about repairing a 189... :)
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Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2729 on: August 19, 2018, 03:16:17 pm »
malagas_on_fire could be right.  Just buying it for parts.  It says not working, parts could be missing..... All pretty clear.  I would just bid what the parts are worth.  The case really does not look too bad.  Maybe a chip in the lens.   

When my friend gave me his 189, I looked into replacing the lens.  I called Fluke service but there were no parts available.  The meter was just too old.  I ran into that with the Fluke 97 scope meters.    They can't service them forever although it seems a few of us wish they did.  Funny, no one wants an 18 year old uni-t.   :-DD

I don't remember anyone asking me to lifecycle that BM235.  I ran a couple of Brymens and they both held up really well.  Plus we have the fact that Brymen actually tests their stuff before it hits the market.  What a concept.   :-DD
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2730 on: August 19, 2018, 04:20:37 pm »
They do cycle test indeed on that brymen's.

No one wants even a 8 year old uni-t for free ( 50b). But Fluke 189 looks more modern than it's age and now it is clear where some brands got inspiration maybe. Now everyone is scavaging for old but good models maybe because of historical or reliability.
   
I've seen the video where you test pocket meters and the uni-t stood better :P What about a lifecycle on that little switch? I've seen a new pocket meter aneng 302 which has EF, true rms on Voltlog channel .. and of course basic input protection...
If one can make knowledge flow than it will go from negative to positve , for real
 

Offline stj

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Re: Handheld meter electrical robustness testing.
« Reply #2731 on: August 19, 2018, 04:52:32 pm »
it actually could be an idiot who thinks it may be just a loose connection and he can do a quick turn-around on it.

there are several youtube channels of such people,
buying stuff for more than they should, admitting they know FA about the product, then stripping them hoping to spot something obvious!!
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2732 on: August 19, 2018, 05:08:08 pm »
They do cycle test indeed on that brymen's.

No one wants even a 8 year old uni-t for free ( 50b). But Fluke 189 looks more modern than it's age and now it is clear where some brands got inspiration maybe. Now everyone is scavaging for old but good models maybe because of historical or reliability.
   
I've seen the video where you test pocket meters and the uni-t stood better :P What about a lifecycle on that little switch? I've seen a new pocket meter aneng 302 which has EF, true rms on Voltlog channel .. and of course basic input protection...


 :-DD :-DD :-DD   :-DD :-DD :-DD
I can see you are one of the UNI-T pocket meter believers!  You are not alone. 

I test with VERY low energy levels.  20J max.  It's nothing.  Now again, keep in mind that the energy available is NORMALLY not dissipated in the meter.  Where's it go?   It's dissipated internal to the generator in the coupling network.  It's not just a bank of caps and a switch like some people have posted.  These people are lost.   The only time a meter would dissipate anything is if it breaks down.    Obviously, some amount will be dissipated in the clamping network (assuming the meter has such a clamp) but this is not what I am referring to.  I'm basically describing a short.    This is when you get to see in some of Fluke's videos where the meters explode. 

****
Let me add also that people have posted how I am slowly damaging the MOVs and how running them at high voltages will degrade them with time.   Again, it's not the case.  Sure the MOVs will degrade but for fun I setup a long term test showing the currents through a meter as I pushed the input voltage far past the meter's rating.  People seem to think the MOVs take the direct hit, which in all of the meters I have looked at, that's certainly not the case.  The MOVs sit behind a series of resistors and PTCs which limits the current available to them.   When I mention above that some energy is dissipated in the clamp, this is divided across all of those components, not just the MOVs.  And when we consider most meters will use the standard 1K resistor in series with a 1.2K PTC and a 1.5KV MOV, not much is dissipated.  It won't suck down that 20J available.   

****

In my testing, when a meter does break down, there is not enough energy available to the meter to do much of anything.  Make a few sparks, maybe blow apart a capacitor or an IC at best.

So we have a UNI-T that does not have near enough clearances and breaks down.   The generator does not provide enough energy to do anything more than make a small spark.  The breakdown voltage is low enough that the meter is basically undamaged.   Now, IMO, that it not a good thing.   The UT90A is like that and its why it continues to stay in my box of tricks.   If my generator had more energy, these meters would ... well.. I guess I'm not sure what would happen but I would like to see it, on the other side of a safety glass case. 

I'm sure you have seen my other generator that I refer to as a half cycle line simulator.  Unlike the fast, high voltage, low energy transient generators I normally use to run these test, this one creates a slow, low voltage, higher energy transient.   I've shown where this generator has no effect on the better class of meters.  Why?  Because they do not break down.  And without a low impedance  path, nothing is going to happen.   I don't use that generator to collect any data from the meters I look at.  There is no mention of it in the spreadsheet.  It's more just to give the viewers some idea of what could happen if a meter were to breakdown. 

In this video, I attempted to finish off the UNI-T UT90A with it.  Again the poorly designed layout saves the meter's electronics.    Don't mistake this for being a robust meter.  It's not! 

https://youtu.be/VHZ5cQPGo64?t=484

You can see, I normally run this test with the meters set to their highest AC voltage mode.  Here's the free HF meter.  Again, if this meter had not broke down, nothing would have happened. 
https://youtu.be/GHWb0kjrIY0?t=72

« Last Edit: August 19, 2018, 06:12:28 pm by joeqsmith »
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2733 on: August 19, 2018, 05:08:49 pm »
Whatever is the case we will soon now on a youtube channel or here :P

Maybe it ill become triple the price after that, since is a relic.  :-DD


If one can make knowledge flow than it will go from negative to positve , for real
 

Online rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2734 on: August 19, 2018, 06:32:08 pm »
They do cycle test indeed on that brymen's.

No one wants even a 8 year old uni-t for free ( 50b). But Fluke 189 looks more modern than it's age and now it is clear where some brands got inspiration maybe. Now everyone is scavaging for old but good models maybe because of historical or reliability.
Despite your meter is probably a fine meter that does its job well, being manual range takes it back 20 years more (at least) - I have a UT54 that is in the same obsolete boat.

A 20 year old DMM from Fluke still has respectable specifications and is full autorange. Depending on where you live, the used market now presents a much wider range of good quality technology of yore, especially if it offers certain brands such as Fluke, Tektronix and others that still carry a lot of value over the years.
Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2735 on: August 19, 2018, 09:29:38 pm »
Keep in mind that i'm not favouring uni-t by any means or have some preference of this brand. and back then it was affordable.  I have a pocket meter uni-t 120c and i do believe in it's specs , its price and a hard case.



My manual range 50b had a lot of luck . It is a obsolete model and has been now replaced with a Brymen BM235 ,  but it is still usable, accurate at least it's digits are better readable than aneng's. No doubt about the fluke's since they seem to never get too old.

It is very common here Uni-t, Fluke, Amprobe, Tektronix, on local stores. Agilent it came here too by online knowledge.

So my point is to check the price, functions, reviews and tests now when purchase something new to get the best value for the money.
If one can make knowledge flow than it will go from negative to positve , for real
 

Offline Towger

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Re: Handheld meter electrical robustness testing.
« Reply #2736 on: August 20, 2018, 08:43:02 am »
What about doing a robustness test on a fluke tester or voltage detector?

fluke 1651b test meter  https://ebay.us/pPhBFu

There is always a steady supply (eBay.co.uk) of faulty units and a number of people/companies making a living repairing them.  So it appears not to take much to damage one. 
 

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2737 on: August 20, 2018, 02:08:59 pm »
Thanks again for the information.

In addtion to the opinion on the meters, when refering to tests, also mention the ones performed by joeqsmith, which gives an idea off the robustness related to DMM.

If people  think that is just capacitor because they see a exponetial decay on the waveform, well ... ask them for  a test JIG and data or just let them read the FAQ. The breakdown voltage and the high speed pulse may pass through less designed protection and hit the IC  even it's low energy, is enought to damage it.



If one can make knowledge flow than it will go from negative to positve , for real
 

Online rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2738 on: August 20, 2018, 02:48:03 pm »
Keep in mind that i'm not favouring uni-t by any means or have some preference of this brand. and back then it was affordable.  I have a pocket meter uni-t 120c and i do believe in it's specs , its price and a hard case.

My manual range 50b had a lot of luck . It is a obsolete model and has been now replaced with a Brymen BM235 ,  but it is still usable, accurate at least it's digits are better readable than aneng's.
I didn't mean to imply that you were a fanboy; sorry. I just wanted to share the same story of a meter still perfectly usable but totally deprived of value... :)

One thing I like about these meters is, as you pointed out, the large digits on its LCD display.

No doubt about the fluke's since they seem to never get too old.
They really age very well; since they are very durable, the main caveat is that there are many terribly battered Flukes on eBay.
Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2739 on: August 20, 2018, 05:04:28 pm »
The breakdown voltage and the high speed pulse may pass through less designed protection and hit the IC  even it's low energy, is enought to damage it.

The gas grill ignitor is a good example of this.   The new gun can output about 15 Amps in under a ns. I compare the grill ignitor against the IEC standards and its hardly worth running it's so low.  I get far worse pokes touching the door knobs in my house during the dry winter months  Yet many of the UNI-T  products I have looked at were damaged by it.   I show why the UT61E is so easily damaged which is a bit different than the problem I see with the UT181. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Vtile

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Re: Handheld meter electrical robustness testing.
« Reply #2740 on: August 20, 2018, 05:23:23 pm »
Have you run any of those low end differential probes everyone is raving about through your test. The results might be interesting.
 

Offline floobydust

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Re: Handheld meter electrical robustness testing.
« Reply #2741 on: August 20, 2018, 08:40:46 pm »


KREOSAN use a taser to impose a high voltage transient on 220VAC mains, and an arc starts "somewhere". Once an arc is established, mains high current flows until I think it extinguishs at next zero-cross, if there is no inductance/capacitance/carbon to sustain it.

Relevance to robustness testing- there's no CDN here so the transient generator's energy alone is not all a multimeter would see? I think the UNI-T UT90A would not have a nice little arc.
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2742 on: August 20, 2018, 09:35:31 pm »
Have you run any of those low end differential probes everyone is raving about through your test. The results might be interesting.
For the most part, I've only ran the meters that are on the list.   Maybe a few fuses and lightbulbs.  If you don't see a video of it, chances are I have not ran it.
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 #2743 on: August 20, 2018, 11:07:35 pm »
KREOSAN use a taser to impose a high voltage transient on 220VAC mains, and an arc starts "somewhere". Once an arc is established, mains high current flows until I think it extinguishs at next zero-cross, if there is no inductance/capacitance/carbon to sustain it.

Relevance to robustness testing- there's no CDN here so the transient generator's energy alone is not all a multimeter would see? I think the UNI-T UT90A would not have a nice little arc.
I am not sure what you are asking.  When I run these tests, I am not superimposing the transients on the AC mains, so there is no need for the CDN.  If you are referring to the stun gun as the transient generator and asking if the meter sees another source.  Then sure.  The mains.   Even with the CDN, it will still see the mains. 

I was not sure if your first part was asking a question or not.  Certainly you can sustain an arc between zero crossings.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2744 on: August 20, 2018, 11:33:31 pm »
If one can make knowledge flow than it will go from negative to positve , for real
 

Offline ProBang2

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Re: Handheld meter electrical robustness testing.
« Reply #2745 on: August 20, 2018, 11:58:03 pm »
Just for interest:

Uni-T seems to have beefed up the input protection on their UT139E and UT139S.
Isolation slots, more diode clamps and PTC´s.
Still rated with CAT III 600V (as the 139A/B/C). Independend certified by Intertek.
Maybe the 139E/S would survive the grill ignitor...
And, I must admit, the display of the 139E looks very nice.
(Somehow are bad displays never an issue of newer Uni-T multimeters...)
 
https://www.youtube.com/watch?v=1CwREOA9RSg&feature=youtu.be&t=19m43s

I can´t resist the assumption: Someone from Uni-T observes this thread...
IMO: They have done very much right. At the first glance, there is nothing obvious to me that is wrong.
And they make progress with every new model. But: I am not an expert...

Therefor I am curious: What is the first impression to the "Master of Sparks and Lightning" himself?
 
« Last Edit: August 21, 2018, 12:16:58 am by ProBang2 »
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2746 on: August 21, 2018, 12:11:34 am »
Maybe they will roll out a new UT181B.  I would make an exception for that meter and run one more UNI-T. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline floobydust

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Re: Handheld meter electrical robustness testing.
« Reply #2747 on: August 21, 2018, 01:20:09 am »
Consider making a mains-voltage measurement and a transient starts an arc within the multimeter - either in a controlled place (inside a GDT) or between shoddy clearances.

Once an arc starts, the transient dissipates quickly but behind it is more (long term) energy, from mains.
In an arc flash incident, this is what causes the heat, burns, injury.

I realized using only GDT's for multimeter protection, without series MOV's, is actually terribly dangerous.
It can survive transient (only) testing, but surely blow up when mains follows through on the arc.
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2748 on: August 21, 2018, 02:01:21 am »
Consider making a mains-voltage measurement and a transient starts an arc within the multimeter - either in a controlled place (inside a GDT) or between shoddy clearances.

Once an arc starts, the transient dissipates quickly but behind it is more (long term) energy, from mains.
In an arc flash incident, this is what causes the heat, burns, injury.

I realized using only GDT's for multimeter protection, without series MOV's, is actually terribly dangerous.
It can survive transient (only) testing, but surely blow up when mains follows through on the arc.
This is not true with every meter I have looked at that used GDTs.   The GDTs like the MOVs sit behind a network of PTCs and surge rates resistors.   It's not like they would put a GDT or MOV right across the inputs to the meter with nothing to limit the current.    Of course, there is one in every crowd.  Someone here actually had a meter that was like this!  But I doubt you will find a meter like this from a reputable company. 

The problem with the internet is so many people presenting things as facts with no data to back them up.   If you feel meters that use GDTs without a series MOV are terribly dangerous, provide some data.


In the meantime,  my vintage Fluke 189 of unknown origins takes to the transient generator.   

https://youtu.be/fHIPGIyLJ3M
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Online HKJ

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Re: Handheld meter electrical robustness testing.
« Reply #2749 on: August 21, 2018, 06:46:46 am »
Maybe this is a Joe protection:



It is found in a UNI-T UT125C and there is a fuse in series with it.
 


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