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 523049 times)

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Offline Fungus

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Heh, I am just thinking of people who are just getting into electronics and what to recommend to them, if I was on a tight budget for my first multimeter I would be hard pressed between the Amprobe and the F-101.
The Fluke lacks current measurement. Definitely not good for electronics work (it's aimed more at electricians).

Amazon lists AM-510 at $37.88. Pretty impressive.
Yep. Seems like a nice meter for that price.
 

Offline Lightages

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It is not my intent to diminish the work and findings of joeqsmith with what I am about to say. His tests show one thing and one thing only, ie the ability of a meter to survive his pulse tests. This is something to consider when buying a meter but it is not the only criteria that a newbie should used in selecting a meter. It is still unclear whether a meter needs to survive and function after a test similar to this to be considered to have met the requirements of the IEC specifications for CAT ratings. It could be, and is my understanding, than multimeters only need to not harm the end user in this failure mode, with a pulse test. If this is the case, then all meters that did not harm the user in this test still meet their CAT ratings under the IEC rules.

The AM-510 is not a good meter just because it passed these tests, rather it is a good meter because it has the functions most needed and works as advertised and for a really good price. The fact that it passed these tests is just another point to consider but not necessarily the most important. I have not seen a full review of the AM-510 and have no direct experience with it. The assessment that it is a good meter, on my part, is that it appears to be well built and has the functions that are necessary for most people, and at a very good price.

I only write this to address the inexperienced or newbies who might take such an impressive set of videos and their dramatic results as being the main criteria for buying a multimeter and focus only that aspect. Safety is important, but none of these videos demonstrated an unsafe condition that I could see.
 

Offline Muxr

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I have some experience with $100 Amprobe meters and they are certainly of good quality. It's a decent brand. So I had my suspicion that Am-510 was going to pass the torture test. This just reaffirms it.
 

Offline Lightages

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Amprobe seems to use three different manufacturers for their products, at least three. The AM-5x0 series seem to be made by Uni-T, at least that what has been speculated by some here on the forums. The AM-270, AM-140 and 160 are definitely made by Brymen. The others in the AM-2x0 series are not clear. The XR series were originally sold by other brands and bought out so I am not sure who actually makes those. The HD series is an unknown to me but they sure seem to be made tough.
 

Online PedroDaGr8

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Amprobe seems to use three different manufacturers for their products, at least three. The AM-5x0 series seem to be made by Uni-T, at least that what has been speculated by some here on the forums. The AM-270, AM-140 and 160 are definitely made by Brymen. The others in the AM-2x0 series are not clear. The XR series were originally sold by other brands and bought out so I am not sure who actually makes those. The HD series is an unknown to me but they sure seem to be made tough.

The HD series I think are old Wavetek models (Amprobe acquired Wavetek and these are the leftovers from that acquisition). Not sure about the XR series, maybe these are wavetek too? Haven't looked into it enough
The very existence of flamethrowers proves that some time, somewhere, someone said to themselves, "You know, I want to set those people over there on fire, but I'm just not close enough to get the job done." -George Carlin
 

Offline retiredcaps

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Not sure about the XR series, maybe these are wavetek too?
XR came from acquistion of Meterman.

Dave did a video review way back in eevblog #6 of the Meterman 37XR.
 

Offline Meter Junkie

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Hi Joe,

Since you are skilled enough to build your own generator, and have demonstrated coupling voltage with the surges, I could use your advice.

I want to couple AC voltage with the surge generator I pictured in this thread. I've researched what inductor should be used to couple this, and 1.5 mH seems the most common recommendation. But, I also want a inductor that can handle a considerable amount of current. So, I found a few 10A inductors, but not a 1.5 mH. In the 10A rating, they have a 1 mH, and a 2.5 mH.  Could you tell me which size inductor would be the best to use with the 1.2/50 pulse width?
 

Offline joeqsmith

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It is not my intent to diminish the work and findings of joeqsmith with what I am about to say. His tests show one thing and one thing only, ie the ability of a meter to survive his pulse tests. This is something to consider when buying a meter but it is not the only criteria that a newbie should used in selecting a meter.

No problem. 

This may be all you took away from this experiment but there was a lot to learn.   I understand, you sell products like hand held meters.   I'm not suggesting you would ever add your own bias to make more sales.   You just need to make sure that you understand what is going on before you use this information as part of your sales pitch.   

Safety is important, but none of these videos demonstrated an unsafe condition that I could see.

That was never a goal.   Comments like this are why I don't think you really understand what can happen.    I covered this subject upfront.  If you don't feel that there are any concerns when an arc is combined with a high energy source, so be it.  Personally, I would not trivialize it to my customers. 

Thanks for the video. The failure of the UT139C seems to have been either a faulty PTC, bad spacing on the tracks that caused an arc over and then the failure of the PTC which then overloaded the MOVs too many times and then every time after the MOVs were a dead short and caused the big flashes.

If you are willing, I think it would make good videos investigating the failure mode of at least some of the meters and see if they could be repaired by just replacing a part or two.

There is no reason to spend a whole lot of time attempting to repair low cost devices like these.  Just buy a new one.   The goal was to find a meter that would survive, then you wouldn't need to be so concerned about replacing it.   I showed where most meters were damaged in the video.     

That said, I did waste some time repairing the UNI-T UT90A.  The control IC was still good.  Three traces had vaporized.  One diode was shorted, 2 resistors were open.  I aligned it and it seems fine.  Nothing I would give away because of the damage to the switch area. 

Sounds like you are most interested in the UT139C.     Q8, Q9, Q2, Q3, R42 and the main control IC are all damaged.    While the heat cracked the insulation around the one PTC, both of them are still fine.   

Most of the damaged meters were ran again at even higher voltages, causing even further damage to them.

I was amazed that you killed the Klein, I liked its small size/lack of features.
   

Klein Tools, not as strong as a set of channel locks!!  :-DD :-DD

The case is glued together.  Indeed, there is a relay in it.   I had attempted to contact  Klein, Fluke and AMPROBE by email.     I would have returned the Klein to them if they wanted it.  I am not sure what the problem is with it.  It appears the source was damaged, not the input.    I tested it again tonight after I ripped it (literally) apart.  It appears the PTC itself will not withstand the voltage.  It arcs and I am sure this caused the damage.    Of all of the meters, the mechanical design of this thing is fantastic, except you can not service it.   


Muxr and Fungus, I agree about the AMPROBE.  It really is a nice meter for the price.   I like it better than the Fluke.    I would like to have have a higher end Fluke, Keysight and AMPROBE to try and destroy (and I don't mean drop it).   

If I had any bias towards one brand during this test, it was with Fluke.   Again, I have to admit, this low cost Fluke really has changed my 30 year old view of their products.   Good job Fluke!!  :-+


Hi Joe,

Since you are skilled enough to build your own generator, and have demonstrated coupling voltage with the surges, I could use your advice.

I want to couple AC voltage with the surge generator I pictured in this thread. I've researched what inductor should be used to couple this, and 1.5 mH seems the most common recommendation. But, I also want a inductor that can handle a considerable amount of current. So, I found a few 10A inductors, but not a 1.5 mH. In the 10A rating, they have a 1 mH, and a 2.5 mH.  Could you tell me which size inductor would be the best to use with the 1.2/50 pulse width?

Sorry, I can't be of help other than suggest your life insurance is paid up.  I just don't know enough about it.  It's not just the current and inductance, that's a lot of voltage.    The company who built your generator may be willing to supply you with information on their networks.   You may find it better to get the right network for your system. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Lightages

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It is not my intent to diminish the work and findings of joeqsmith with what I am about to say. His tests show one thing and one thing only, ie the ability of a meter to survive his pulse tests. This is something to consider when buying a meter but it is not the only criteria that a newbie should used in selecting a meter.

No problem. 

This may be all you took away from this experiment but there was a lot to learn.   I understand, you sell products like hand held meters.   I'm not suggesting you would ever add your own bias to make more sales.   You just need to make sure that you understand what is going on before you use this information as part of your sales pitch.   

Safety is important, but none of these videos demonstrated an unsafe condition that I could see.

That was never a goal.   Comments like this are why I don't think you really understand what can happen.    I covered this subject upfront.  If you don't feel that there are any concerns when an arc is combined with a high energy source, so be it.  Personally, I would not trivialize it to my customers.

Your videos on the whole subject did provide much to learn on the subject of high voltages with high energy and the protection against them. I did not say that your videos were only about the ability of a meter to survive his pulse tests. I said that the tests of the meters only demonstrated that about the multimeters being tested.

I think you misunderstood my intentions and/or the meaning of my message. Because of this I also think you misunderstand my knowledge and experience with these kinds of things. I specifically said that these tests should not be the focus of buying a multimeter and that there are other considerations too. You yourself have said that these tests are not up to the standards required by the IEC and so I am merely saying that they should be considered incomplete to determine the safety of a multimeter. To be clear, the multimeters I distribute and sell are only Brymen, in most of South America, no where else, and no other manufacturer. I take safety seriously and my history here on the forums can vouch for that. Brymen also takes safety seriously. All of their current lineup meet the latest IEC requirements, and all are 3rd party tested by UL.

My message was to those looking to decide what multimeter to buy, as inexperienced and new comers to the hobby, and possibly thinking that your videos should be the sole focus for a purchasing decision. It is similar to a person focusing only on the accuracy specification on DC volts and not considering the other specifications that also make a big difference.

I also fully understood the goal of your tests and videos. I never said anything otherwise. I also fully understand the problems of safety and the serious nature of electrical hazards. To imply that I am trivializing the safety of my customers is to not understand what I have been doing here on the forums for years, and to not understand what I said in that post. I get the feeling that you have never read anything I have posted before on this subject except here in this thread. That could explain why you could accuse me of being casual on the subject of multimeter safety.

Thanks for the video. The failure of the UT139C seems to have been either a faulty PTC, bad spacing on the tracks that caused an arc over and then the failure of the PTC which then overloaded the MOVs too many times and then every time after the MOVs were a dead short and caused the big flashes.

If you are willing, I think it would make good videos investigating the failure mode of at least some of the meters and see if they could be repaired by just replacing a part or two.

There is no reason to spend a whole lot of time attempting to repair low cost devices like these.  Just buy a new one.   The goal was to find a meter that would survive, then you wouldn't need to be so concerned about replacing it.   I showed where most meters were damaged in the video.     

That said, I did waste some time repairing the UNI-T UT90A.  The control IC was still good.  Three traces had vaporized.  One diode was shorted, 2 resistors were open.  I aligned it and it seems fine.  Nothing I would give away because of the damage to the switch area. 

Sounds like you are most interested in the UT139C.     Q8, Q9, Q2, Q3, R42 and the main control IC are all damaged.    While the heat cracked the insulation around the one PTC, both of them are still fine.   

Most of the damaged meters were ran again at even higher voltages, causing even further damage to them.

Wow, that is a bunch of damage to the UT139C. It certainly looked like it was well protected but that is why multimeters need third party testing to prove their claims. Even then, all the damage and arcing was contained in the housing, from what I could see, so it is still not evidence that it didn't match its CAT rating. (Take note, I never have, and am not saying now, that you are claiming to verify the CAT ratings nor that your videos are to be taken as evidence for such a test)
 

Offline Meter Junkie

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Sorry, I can't be of help other than suggest your life insurance is paid up.  I just don't know enough about it.  It's not just the current and inductance, that's a lot of voltage.   

I find that statement kind of funny, since it is coming from a guy who was doing his testing with the open meter a few feet away, and even changing switch positions while timing out the surges. At least I built a blast chamber made with half inch Lexan for my testing.

But, I get you not wanting to give advice if something went wrong on my end.  I would have not coupled through 400V.  I would have started with less than 100V, and put some 10A HRC fuses in line to limit any danger. The spec says that blowing the circuit breaker would be a failure to this test, so opening those fuses would be an indication of failure. That would help limit any danger.
 

Offline joeqsmith

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Sorry, I can't be of help other than suggest your life insurance is paid up.  I just don't know enough about it.  It's not just the current and inductance, that's a lot of voltage.   

I find that statement kind of funny, since it is coming from a guy who was doing his testing with the open meter a few feet away, and even changing switch positions while timing out the surges. At least I built a blast chamber made with half inch Lexan for my testing.

But, I get you not wanting to give advice if something went wrong on my end.  I would have not coupled through 400V.  I would have started with less than 100V, and put some 10A HRC fuses in line to limit any danger. The spec says that blowing the circuit breaker would be a failure to this test, so opening those fuses would be an indication of failure. That would help limit any danger.

These videos certainly do not show proper safety, nor was it my intent to ever do so.    The ring, watch, use of 2-hands, use of home made non certified probes, the list goes on.     Without the line voltage, I am working on sub 20J.   Still lethal but it's a very controlled event and I am comfortable working on things of this nature.    The thing you did not mention is that I posted once how I had stopped testing because I was burned out and started to make some mistakes.       

If you look at what goes into a normal CDN you will find there is more than just an inductor.   Our network is about 2X larger than the generator.    Even with our setup, there is enough energy going back on the line that we have damaged other equipment in the lab.     

Yes, I did run a simple experiment using a single inductor to isolate a supply from the transient.  It was a very scaled down test.   I would hope the thing people took aware from this was how the arc started the event and the lower voltage sustained it.   Not that a simple inductor was all that was needed to isolate a real surge from the mains.   

One thing to consider is what tests should be ran to determine how electrically robust a multimeter is?  Sure dropping it, putting it into a bucket of water and plugging it into your AC outlet are all easy tests to perform but really it seems there should be some sort of standards the products could be tested to besides surge.   

The  IEC surge was the closest thing I could come up with.   As I noted, I dialed it way down lower than the IEC calls for and worked my way up.   Sure it does open the doors for people to read the standards are argue that they only need to fail safe.   :blah: :blah: :blah:   There are going to be people that don't get the point of the test.   

Again, I have no idea if the meters really would fail in such a way as not to meet the IEC standards.  If you want to know this, I would suggest you run them at an accredited lab.   This was not the intent!   If you want to know if one meter is more robust than another, I think the tests I have ran give a fair idea.   If you feel that the testing I performed is not an indicator of this, you are free to come up with your own tests and post them.     I would be very interested and welcome this and am sure others would be as well.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Muxr

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The thing you did not mention is that I posted once how I had stopped testing because I was burned out and started to make some mistakes.         
That certainly must have taken a lot of time to do. I certainly enjoyed the experiment and I appreciate you sharing it with us.
 

Offline Meter Junkie

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Here is a video I found on Fluke's testing lab, and all the tests they do.  The surge and over voltage testing are at the very end.

http://assets.fluke.com/video-MULTI/44095317_fluke_safety_lab.html
 

Offline Lightages

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I can also say that I enjoyed them too. I think many people were grateful for your time and expense that put forward for the benefit of all.  :-+
« Last Edit: June 27, 2015, 10:55:48 pm by Lightages »
 

Offline joeqsmith

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I can alssay that I enjoyed them too. I think many people were grateful for your time and expense that put forward for the benefit of all.  :-+

 :-+

It would have been nice to run comparisons like this on more meters but I think going forward I'll leave this to others with more resources available to them.   

I still plan to put the winner up against the Fluke 28 II and/or the Keysight U1272A and at least see of one of these meters can withstand the testing that the low cost meters have.   My fear is that some of the $50 meters may actually hold up better and I may damage a meter costing more than the entire amount spent so far.     

It's been almost one month to the day since I started looking into running this experiment.  Enjoy the finals....

https://www.youtube.com/watch?v=RBkjr3b5hQo&feature=youtu.be

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

Offline John Coloccia

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"Looks like a hazardous condition to me"

 :-DD :-DD :-DD
 

Offline Muxr

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Good stuff Joe! That intro was fun.

If I was Fluke I would send you a new 28-II or an 87V  ;D
 

Offline siggi

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Great videos, nice objective robustness criteria. Sure beats "feels solid", "better feeling plastic" reviews :).
I didn't care much for the DMM scat, but to each his own.


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Online tautech

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 :clap:  :-+

Gotta love your evil lady.  >:D

Great job Joe, it'll be interesting to see if any manufacturers contact you with revised models for you to retest.  :-DD
Avid Rabid Hobbyist
 

Offline Meter Junkie

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Great job Joe!!

Now that I know the top meter, I wouldn't mind getting the Fluke 101, and see how much higher it can go. Now, I wouldn't have to buy 10 meters like you did, I could get just the one.  It would be interesting to see how far beyond 6kV it could go, since I could take it all the way to 12kV.

Too bad none of the companies you contacted got back to you. Since Fluke was the winner, it would have been nice for them to send you something else. Maybe they still will. But, it sucks that no companies even acknowledged you emails.

You should consider selling those boxes. Like you said, they go for 10's of thousands.  You could make a killing selling yours to people who can't afford the big ones.
 

Online Vgkid

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Thanks for all of the work you have put into these test, thumbs up from me.  :-+
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Offline ivan747

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Thank you for sharing your findings and involving us in the process too.
 

Offline saturation

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I second this wholeheartedly.  Great job. :clap:

More later, but one thing you could use your surge generator for doing the exact same tests are evaluating surge protectors, they are more improperly built compared to DMMs and have similar input protective circuitry.  However the let-through voltages are lower on the MOVs and they are more subject to burn violently as they can be exposed to sustained overvoltages caused by say, lost-neutral events, as in the way home distribution is done in the USA.

Its used by a wider audience and models are introduced very often, you can make a business, or at least an endless series of review videos, checking them.

https://www.eevblog.com/forum/suggestions/surge-protectors-scams-and-saints/msg3891/#msg3891


Great job Joe!!

Now that I know the top meter, I wouldn't mind getting the Fluke 101, and see how much higher it can go. Now, I wouldn't have to buy 10 meters like you did, I could get just the one.  It would be interesting to see how far beyond 6kV it could go, since I could take it all the way to 12kV.

Too bad none of the companies you contacted got back to you. Since Fluke was the winner, it would have been nice for them to send you something else. Maybe they still will. But, it sucks that no companies even acknowledged you emails.

You should consider selling those boxes. Like you said, they go for 10's of thousands.  You could make a killing selling yours to people who can't afford the big ones.
« Last Edit: June 28, 2015, 12:06:00 pm by saturation »
Best Wishes,

 Saturation
 

Offline dom0

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Niiiicee!
,
 

Offline patw4pbj

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Fun and educational thread.  Thanks.


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