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Handheld meter robustness testing

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The latest spreadsheet is now available on GoogleDocs here:

Answers to Frequently Asked Questions may be found here:

Because the generator used for these tests changed from the first round to the second, it is difficult to correlate the data.  The UNI-T UT90A that was used in the first round had been repaired and tested again in the second round.   You will notice that while it survived a 3.2KV 2 ohms pulse in the first round, it fails at 1.5KV 2 ohm during the second round.   This is because the pulse width on the new generator was increased by a fair amount to more closely represent the IEC standard.   

You will also note that the AM530 did not make it as far into the tests at the AM510 did in the first round.  Some of the meters that 5KY provided me with were a much higher grade.   

Because the generator used in the first round of testing had to be rebuilt for each test ran, when the Fluke 87V was finally tested we only knew it was not as robust as the winner of the $50 shootout, the Fluke 101.    During the second round, enough people had asked me about the 87V that I went ahead and reran one and was amazed that it did so poorly.   

I have very few rules when it comes to leaving comments on my YT channel. 

1) Don't personally insult anyone.  Me or otherwise. 

2) Don't use my channel to post ads.  I don't run ads and don't ask for donations.  I am not making any money by posting this content.  For you to try and profit from my efforts is in very poor taste.           

3) Don't ask about how to modify a meter or how to construct a transient generator like I show.   Also, don't attempt to post lists of materials and don't try to tell others how to modify their meter.  If I ignored you, you should be fine.  If you are persistent most likely you will get banned.   There are many concerns when it comes to working with higher voltages and currents, even at the levels I show in the videos.       
I have YT filters setup.  If really don't care if your vocabulary is limited but the filters are fairly effective at picking up people who are intent on breaking the first rule.  Just be aware they are being used.   

If you want to post about my channel to others, please don't post false statements about the tests I am running.  Obviously I don't have any control over this.  I am just asking that if you don't understand the tests being ran, maybe just point them to the FAQs and call it good.   

If the above rules bother you and you feel you can't follow them,  please feel free to unsubscribe. 


Table of Contents

First attempts at designing a waveform generator

Selecting the first set of $50 USD meters to run

Initial testing of the waveform generator

The first set meters have arrived and round I of the testing begins

Home made high voltage attenuator

Fuses are now banned from testing and the low energy levels are explaine

From here on, its always a 2 ohm source....

The UNI-T UT139C shows up late from China.

Member Meter Junkie shows off their surge generator

First set of $50 meters, Semi Finals

The UNI-T UT139C joins the remaining four meters and is damaged

First set of $50 meters, Finals

Member Meter Junkie runs a second Fluke 101 on their IEC combo generator at 12KV

I push the Fluke 101 to 13KV 100us FWHH

Hackaday runs a story on the testing

The first of the higher cost meters, the Fluke 87V

Member TechnologyCatalyst(5KY) steps into the game with a Round II of meters

Designing a programmable transient generator

Testing the new transient generator

Testing the second set of meters, Round 1

Testing the second set of meters, The Finals


Rebuilding the generator (20KV, 50us FWHH), the Fluke 107 is pushed to its limit

UNI-T UT90A plays music

Designing the  half cycle AC line simulator

Initial testing of the Half cycle AC line simulator

The Fluke 17B+ Review

A second UNI-T UT139C is tested

The Fluke 115 Review

My old Mastech MS9508 / Cen-tech P37772

Discussing input protection circuits

The SONY Cyber-shot DSC-RX10M2 high speed Sony camera

The UNI-T UT15C VoltStick

The Keysight U1231A

First look at the current inputs


The HIOKI DT4252

The UNI-T UT181A

Talking about ESD

The UNI-T UT181A Repairs

Low cost pocket meters

Testing various DMM probes

The TPI 194 II

Temperature testing Part I

Modifying the UNI-T UT61E (added robustness, backlight)

YX-360 analog meter

The Brymen BM235

Pen Meters

Modifying the UNI-T UT61E (Improving temperature drift)

The CEM DT-9939 / Extech EX540

Designing an ESD gun

The Woods DMMW3 pocket meter

The ANENG meters

Testing various DMM high current shunts

Modifying the UNI-T UT61E (20A measurements)

Modifying the UNI-T UT61E (Low Burden Voltage)

SIBA branded UXCELL Multimeter Fuse, Real or Counterfeit

The Gossen Metrawatt Metrahit Ultra M248B

The Gossen goes to the chamber along with some lower cost meters

Dave sends a 121GW prototype

Testing Dave's ASTM fuses

Mr Joules

My first Fluke 189, Finally a Fluke meter that I would actually use

PlastX, restoring lens

Dave runs a crude HV test

The ANENG 8008

Transient Testing Resistors

ANENG, 14KV or Bust

Selector Switch Life Cycle Testing Part I

The ALL-SUN EM135 Automotive Meter

Selector Switch Life Cycle Testing Part II

Harbor Freight's CEN-TECH 95670, the rebranded E0SUN EM129 automotive meter

Upgrades to my temperature chamber made from a meat packing box

The Brymen BM319s Automotive Meter

The Brymen BM869s 50,000 Cycle Switch Life Test

Repeating the Brymen BM869s Transient Test

The Brymen BM839 Professional Meter

The Brymen BM869s, It's 14KV or Bust

Repairing the homemade wideband high voltage probe

The Fluke 87V, hot off the production line, full on testing

The Fluke 87V, Extended High Voltage Testing

The Fluke 87V, Another look at the old 87V and why it failed

The Fluke T6-600, a responce to AvE

Appling 1KV to various meter's, a responce to VoltLog

Member Kean's Damaged 121GW, trying to determine the root cause

Lighting strikes and damages some of my test equipment

The MeterK MK01

Transient Testing a Vintage Fluke 189

The Brymen BM27s / Amprobe PM55A, is it really as bad as member True claims?

Applying 1KVDC to various 4.7M resistors, preparing for a possible future test

Viewer questions and comments

The Brymen BM869s is directly exposed to several Watts of 7MHz CW

The Brymen BM27s / Amprobe PM55A, Round I of testing

Demonstrating using Labview to communicate w/ 121GW and UT181A over BlueTooth
Vaseline?  Yes, that's right.  Future Darwin Award

The Owon B41T+ review

Measuring battery life

Rebuilding my first digital volt meter, the Fluke 8000A

The Yokogawa TY720 review

Vibration Testing

The Brymen BM27s pocket meter,  Round II  low battery, cold Winter months and vibration

Any muiltimeter with a legitimate Cat III rating can handle Cat II circuits. 

The higher the Category rating, the higher energy the meter is safe with. You can always use a Cat III or Cat IV meter on lower rated circuits, but not the other way around....

After doing many searches on this site, I see a lot of posts about how meters are rated and tested.  There were even a few posts where people attempted to put some high voltage on them.   To be clear,  my plan is not to do an insulation test.   I am interested in surge.   My plan is to construct a small generator that I will use to weed out the worst meters.   If any meters are working after my basic test, I plan to further test them to the actual standards.   

CAT III 600 would require the surge use a 2 ohm source with a 6KV peak (3000 Amps peak).   This would ride on top of the AC.  Nasty stuff.  CAT II uses a 4KV peak with a 12 ohm source (333 Amps peak).   The test is the standard 8/20 waveform with a short applied or 1/50 with an open. 

A few good articles if you are interested:

To start out, I need a generator that can create something close to the CAT II waveform.    You saw from my first post my quick generator.   This thing could hardly do much of anything.   

Over the last few days I built up several circuits, blew up every bench supply I have (an repaired them) and am close now to what I am looking for.   

My plan to do a sort of hybrid waveform.   I plan to limit the peak to 2KV but stay with the 2 ohm source.   I also plan to limit the duration of the pulse (not sub 1.0us like  my first throw together setup).   I plan to cut it in half.   For a CAT III meter this will be no problem what so ever as it is 1/3 the peak and half the duration with the same impedance.   

The second generator I cobbled up worked fairly well with a 12 ohm source but I wanted something that could do the above and put out that full 1000 Amps.   

The DOE Handbook Electrical Safety is available on-line.   I have played with KV low current equipment most of my life from TV and radios to modern test equipment.   So I am not concerned about this little project.    However,  I thought it would be interesting to highlight a few paragraphs from this document.

To create the waveform, I have been using a 500mA wall mount supply.   I use this to create a high voltage signal that is rectified and stored into a bank of capacitors.   

In Fig. 3-4. Complete electrical hazard classification system showing 5 major groups and 54 classes.  You can see capacitors are called out as Classes 3.x.   They are broken down by operating voltage. Safety Practices
An analysis of high-voltage circuits should be performed by a qualified person before work
begins unless all exposed energized parts are guarded as required for high-voltage work. The
analysis must include fault conditions where circuit current could rise above the nominal rated
value. Depending on the results of the analysis, any of the following may apply:

1. If the analysis concludes that the current is above 5 mA or stored high-voltage capacitive
energy is above 1 joule for voltages between 100 and 400 V DC, or above 0.25 joule for
voltages equal to or greater than 400 V, then the work is considered to be energized work
and should be performed in accordance with Chapter 2, "General Requirements" and/or
Chapter 3, "Hazard Analysis." See Chapter 3 for details on electrical hazard classification.
2. If the analysis concludes that the current is between 0.5 mA and 5 mA and between 0.25
and 1 joules, then the worker may be exposed to a secondary hazard (e.g., startle reaction)
that must be mitigated.
3. If the analysis concludes that the current is below 0.5 mA and below 0.25 joules, then the
worker exposure is minimal and no special precautions are required, even for high voltage

From above, I plan to run the storage caps at 2KV.  Well above the 400V limit.  Looking at Fig. 3-9. Hazard Classes 3.x, capacitors, > 400 V, we can see that for 1-10 Joules, it is considered Class 3.3d.    This is a Red colored box.   

10) A red Class (X.3) indicates injury or death could occur by proximity or contact; often
the hazard is shock, contact burn, or arc-flash burn; engineering controls are
necessary for operation (e.g., listing or equipment approval), and administrative
controls are necessary for electrical work in this Class.

It should be obvious what the above means....

After making some calculations for the controller and output stages I ran a quick simulation of both.     Attached you can see the simulated response with a 1Meg and a 0.1 ohm load attached.   Not quite a 1000 Amps in the simulation. 


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