Poll

Are you interested in seeing more handheld meters tested?

This testing is pointless! Please STOP damaging these meters!
3 (6.5%)
 Yes, I would like to more meters tested.
43 (93.5%)

Total Members Voted: 46

Author Topic: Handheld meter electrical robustness testing.  (Read 495305 times)

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Online malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2975 on: October 31, 2018, 08:37:26 pm »
I only watch the video till the labview interface because it was too late and damn, very nice. Very Good algorithm for using the A/D. looks like the BLE interface may fit the uni-t 81b scope. I've contacted uni-t but no answer yet.

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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2976 on: October 31, 2018, 10:08:43 pm »
Just to be clear: I didn't request Vaseline, that was 001.  I just suggested the spark gap test.  :D

If that's a concern for you, next time perhaps think more, post less? 

Simple test: Make a spark gap, put Vaseline on it, see if it stops sparking.  :popcorn:

(and if it stops, how much higher do you need to go to get it to spark again?)

I provided a link to the thread in the description for those wanting to read what's been posted and follow along.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline Fungus

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Re: Handheld meter electrical robustness testing.
« Reply #2977 on: October 31, 2018, 10:17:08 pm »
Just to be clear: I didn't request Vaseline, that was 001.  I just suggested the spark gap test.  :D

If that's a concern for you, next time perhaps think more, post less? 

Not a problem for me. I think it was a good test, worth documenting.

So
I want to protect selector from arc at lamels
Is silicone best isolator than air?

If you think there might be an arc then grease isn't the answer (and probably won't help).

Change the operating procedure, wear protective gear, get a better meter if necessary.

I was wrong, it helped.  :-//

(on a simple spark gap)

...but I stand by the "If you think there might be an arc then grease isn't the answer" part.

(and if you're gonna apply grease, use grease that's designed for the job)
 
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Offline Fungus

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Re: Handheld meter electrical robustness testing.
« Reply #2978 on: October 31, 2018, 10:32:08 pm »
I was wrong, it helped.  :-//

I should probably qualify that:

a) Putting a big blob of non-conductive grease on a spark gap will obviously help. This was demonstrated.

My concern is that if you put it on the wiper contacts of a multimeter then it's going to get spread very thin after you turn the selector a few times. How effective will it be then? That's a lot harder to quantify - it depends on the meter.

b) The OP in the other thread seems to think a random applications of grease will make his meter safer. I don't share that view at all. I think he should buy a properly designed meter, one that won't arc in the first place.
 

Online malagas_on_fire

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Re: Handheld meter electrical robustness testing.
« Reply #2979 on: October 31, 2018, 10:42:52 pm »
Now it is using my old uni-t 50b and read the manual before using it. They are the acessible meters.
The one that i've got is the uni-t ut139A , the worst of the 139 line. At least it has ceramic fuses for the claimed voltage, it has enough grip and simple to use. It will be out of reach for modifications.

I've not looked at the 139A.  Just in general have not been very impressed with the UNI-T product line.  I still like that 210E clamp (as a clamp only). I'm not aware of anyone I know who bought one having any problems with it yet.  The 181A could also be a very nice meter with a few changes.

The uni-t 139A it should have in theory the same input protection as the 139C, but with less functions, counts, etc. The 210E  clamp meter was out of stock and i have already one clamp meter.  So far i'm quite happy with Eevblog BM235 since it has plenty of functions, good input protection , nice digits, decent backlight and battery life and that i use to monitor AC current which it is more accurate.

Edit Here is a picture of the actual meter with D.U.T.
« Last Edit: October 31, 2018, 11:04:32 pm by malagas_on_fire »
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Offline stj

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Re: Handheld meter electrical robustness testing.
« Reply #2980 on: November 01, 2018, 12:14:42 am »
did anybody seriously think putting PETROLeum jelly on a spark-gap or switch would be a good idea??  :palm:
it's one of the primary ingrediants of a molotov coctail!!
 

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Re: Handheld meter electrical robustness testing.
« Reply #2981 on: November 01, 2018, 02:23:39 am »
That would ignite the video of joesmith a lot, with possible flames :S Even the 230V 6V isolated mains does a little spark between 1mm or less on D.U.T. which is dangerous .
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Offline floobydust

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Re: Handheld meter electrical robustness testing.
« Reply #2982 on: November 01, 2018, 04:32:39 am »
There are many long, religious threads about lube in DMM rotary switches.
I'm experimenting with Krytox GPL 105.

It's basically liquid Teflon in a fluorinated-base. Used in Aerospace and MILSPEC.
No silicones, no petroleum, non-reactive, non-flammable. It's the best lube out there, but very expensive. Doesn't evaporate.
Oddly enough, it's used by car dealerships to stop weatherstripping from squeaking due to body flex.

Krytox 105 is a medium thickness oil and I think 205 is a grease.

 
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Offline stj

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Re: Handheld meter electrical robustness testing.
« Reply #2983 on: November 01, 2018, 04:33:22 am »
they could spray the switch area with teflon and be done with it.
i cant see any point though.


grease actually makes sense.
if you think about it, the contact area is a thin line down the center of the pads,
so if you increase the gap from the space between the pads to the space between the centerline of the pads then you increase the breakdown voltage.
[in theory]
 
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Offline 001

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Re: Handheld meter electrical robustness testing.
« Reply #2984 on: November 01, 2018, 06:19:32 am »
Hi!

What is "High Voltage" actually?
Is it 200V, 600V or 1200V? DC or AC? What freq?
 

Offline Cliff Matthews

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Re: Handheld meter electrical robustness testing.
« Reply #2985 on: November 01, 2018, 06:26:20 am »
What is "High Voltage" actually?
Is it 200V, 600V or 1200V? DC or AC? What freq?
https://en.wikipedia.org/wiki/High_voltage#Definition
 
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Offline 001

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Re: Handheld meter electrical robustness testing.
« Reply #2986 on: November 01, 2018, 06:29:57 am »
 

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Re: Handheld meter electrical robustness testing.
« Reply #2987 on: November 01, 2018, 09:21:36 am »
High voltage in DMM,  would be around what manuals ( Safety Information ) of  describe on the first pages to be aware of probe techniques to prevent hazards, starting at 30Vrms or 60Vdc .  Tthe meter could have a LED  of the HV or starts beeping a lot...

 

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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2988 on: November 01, 2018, 10:03:49 am »
It's the best lube out there, but very expensive.

Like I haven't heard that one before.   :-DD 

When I see something hold up as well on that 50,000 cycle life test than the Fluke 17B+'s dry contacts, I will surely let people know.  I would rather see a properly designed switch than spend my time searching for the world's best lubrication. 


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 #2989 on: November 01, 2018, 10:12:35 am »
High voltage in DMM,  would be around what manuals ( Safety Information ) of  describe on the first pages to be aware of probe techniques to prevent hazards, starting at 30Vrms or 60Vdc .  Tthe meter could have a LED  of the HV or starts beeping a lot...

Quote
The numerical definition of "high voltage" depends on context.
I tend to agree with their opening sentence.  In the context of a handheld DMM normal use, I lean more towards what you wrote and the wiki section on safety. 

When I test meters, I talk about my low voltage transient generator.  It's 6KV which may seem like a lot but in the context of the transients I can generate, it falls way short of the 15KV I tested the Fluke 107 at.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline wasyoungonce

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Re: Handheld meter electrical robustness testing.
« Reply #2990 on: November 01, 2018, 10:48:31 am »
......Krytox GPL 105...................Used in Aerospace and MILSPEC..................

Good old Krytox...the only stuff we were allow to use on Aircraft oxygen systems.  Not cheap though.  But I suspect the Military sales markup was a few 1000%
I'd forget my Head if it wasn't screwed on!
 

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Re: Handheld meter electrical robustness testing.
« Reply #2991 on: November 01, 2018, 12:18:52 pm »
High voltage in DMM,  would be around what manuals ( Safety Information ) of  describe on the first pages to be aware of probe techniques to prevent hazards, starting at 30Vrms or 60Vdc .  Tthe meter could have a LED  of the HV or starts beeping a lot...

Quote
The numerical definition of "high voltage" depends on context.
I tend to agree with their opening sentence.  In the context of a handheld DMM normal use, I lean more towards what you wrote and the wiki section on safety. 

When I test meters, I talk about my low voltage transient generator.  It's 6KV which may seem like a lot but in the context of the transients I can generate, it falls way short of the 15KV I tested the Fluke 107 at.   

Humm  i was out of context maybe or forcing it, assuming what comes first in the manuals and forgot the IEC standards , CAT ratings  that are also mentioned and adds to another section of high voltage surge.

About lubricants i don't have a concrete opinion, but follow the recommended stuff as in mechanical parts by the brand
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Offline floobydust

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Re: Handheld meter electrical robustness testing.
« Reply #2992 on: November 01, 2018, 01:27:17 pm »
It's the best lube out there, but very expensive.
Like I haven't heard that one before.   :-DD 
When I see something hold up as well on that 50,000 cycle life test than the Fluke 17B+'s dry contacts, I will surely let people know.  I would rather see a properly designed switch than spend my time searching for the world's best lubrication.

Strange, it wasn't dry (on the PCB) for the old 87:
https://www.eevblog.com/forum/beginners/lube-dmm-selector-switch/msg1248833/#msg1248833
 

Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2993 on: November 01, 2018, 06:43:48 pm »
It's the best lube out there, but very expensive.
Like I haven't heard that one before.   :-DD 
When I see something hold up as well on that 50,000 cycle life test than the Fluke 17B+'s dry contacts, I will surely let people know.  I would rather see a properly designed switch than spend my time searching for the world's best lubrication.

Strange, it wasn't dry (on the PCB) for the old 87:
https://www.eevblog.com/forum/beginners/lube-dmm-selector-switch/msg1248833/#msg1248833
If we are talking about Fluke,  I am guessing that the grease is being used as a lubricant and not to increase the breakdown voltage.  I assume the meters are designed not to arc by design (creepage, clearance).    Again, a GUESS.  I am not presenting this as a fact! 

It's possible that the 17B+, being a newer design has a better switch design than the 87.  Better materials, spring tension, surface area, contacts, thickness......  The parts making up the 17B+ switch assembly even after the 50,000 cycles are still all in very good condition. 

You would think the 87V being what some consider the best meter mankind has ever created,  would have the best switch design.  Again it uses dry contacts.  19:00 - 27:00 may be of interest. 

https://youtu.be/dQPcAs0EEqY?t=1099

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

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Re: Handheld meter electrical robustness testing.
« Reply #2994 on: November 01, 2018, 11:47:02 pm »
Well the fluke 87V is one of the most known and referenced meters , for it's functions, but considering the best meter of mankind has ever made maybe it stay's on the time when it first got into market.  It's a very subjective matter.

Now there are more brands, and meters like brymen BM867s , Fluke 117+, keysight U1282A for example that have unique build quality features into it. I'd like to grab the keysight, put on it on a bag to my back, swim with that meter and of course let it dry a little bit to test measurement. 

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Re: Handheld meter electrical robustness testing.
« Reply #2995 on: November 06, 2018, 09:49:55 am »
Hi i found another feature or bug in one of my meters, it is the clamp meter uni-t 204A.. the one that is not true RMS... if it enters sleep mode and you wake up with any button it doesn't sleep anymore.... The other meters like bm235, ut139A they enter sleep mode ever ,and after awaken by buttons.

It is still on for hours doing the job of discharging the rechargeable 9V battery...  in volts range of course... Maybe i should open another thread....

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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2996 on: November 29, 2018, 06:01:56 am »
Three new handheld DMM videos in the works. 

With True never posting again, I had decided to run even more tests on the Brymen pocket meter.   That has been going nonstop since the first video was made.  I plan to repair one of the meters we damaged a long time ago and see if I can harden it.  And finally, I've had a few people requesting new meters be ran.  I've been watching reviews and picked one out.   All the reviews I saw for it from the big channels give it the old thumbs up.   Sorry, it's not the 121GW.

How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Re: Handheld meter electrical robustness testing.
« Reply #2997 on: November 29, 2018, 09:18:20 am »
Hey new meters to be put on the run :P Are some anengish types?

Did you ever tester one of the Non-Contact Voltage Pen tester? Some of them claim CAT IV .... CATII .. 1000V or none..

Here are some examples:

CAT II:

https://ebay.us/bcEHuF

CATII:

https://ebay.us/xF6EeJ

CATiV ( Fluke):

https://ebay.us/qEjMiQ


There are lots of models.... and a mixed CAT ratings on them... and of course there is always a aneng...:

https://ebay.us/qEjMiQ

... with a proper CAT rating :P
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Offline joeqsmith

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Re: Handheld meter electrical robustness testing.
« Reply #2998 on: November 29, 2018, 01:49:50 pm »
Hey new meters to be put on the run :P Are some anengish types?

This will be a brand I have not looked at yet.  There are many reviews and tear downs of it.  Lots of positive feedback.  Thing is, my transient generators don't seem to care about all of that.   

Did you ever tester one of the Non-Contact Voltage Pen tester? Some of them claim CAT IV .... CATII .. 1000V or none..

There is a link to an on-line spreadsheet in the very first post of this thread which contains data for every handheld meter I have looked at.  If it's not on that list, I have not ran it (except for one or two exceptions).   

How would you propose I would test these non-contact testers?    You know who would be a good person to run them would be John Ward.  He does a fair amount of electrical testing.    If PhotonicInduction were still making content, he would be another good source. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2999 on: November 29, 2018, 02:11:46 pm »
Hey new meters to be put on the run :P Are some anengish types?

This will be a brand I have not looked at yet.  There are many reviews and tear downs of it.  Lots of positive feedback.  Thing is, my transient generators don't seem to care about all of that.   
A certain Japanese manufacturer?  ;D
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