Handheld meter robustness testing

[joeqsmith]

I wonder if there is something that could be adjusted to get it to read higher than 10MHz.   Pretty sad after seeing that pocket meter up at 200MHz.

[joeqsmith]

" I don't understand why this guy damages all multimeters?!?"
 

[MacMeter]

" I don't understand why this guy damages all multimeters?!?"
 

And .... we just love ya for doing it!

[joeqsmith]

" I don't understand why this guy damages all multimeters?!?"
 

And .... we just love ya for doing it!

Brymen with my 1mV/A shunt and KT6000 direct.  No doubt the Brymen and shunt will take 20A.  I wonder about the leads they supply with this thing.  Maybe I should include them when I run it.

[joeqsmith]

Ig Saturation   5 days ago   
Excellent as always Joe.  It blew close to where I thought it would, and the arc energy atomized the tracings with it.  You could get another blast off that meter by doing the 10A input.

It does appear the 10A circuit survived.  We can't have that.   Time to get the window fan out....

[BroMarduk]

The manual has a CAUTION about auto range only in frequency mode.   I wonder if they won't switch to the low range.  Did you try both the mv and volts functions?  Same results?

With V setting, I can get 100KHz at 20V (the V max on the Func Gen) or 80KHz at 5V.   Much worse than with mV

1Hz seems to be the bottom of the range on both V an mV.   

I couldn't find any way to turn off AUTO mode for frequency.

[joeqsmith]

It won't be long now....  Can it out survive Fluke's golden standard 87V...

[joeqsmith]

The spreadsheet and video for the KT6000 have been uploaded.

[BroMarduk]

One thing I noticed was that the Duty Cycle % go way off as you increase past 100KHz.  Both sine and square waves were spot on to 100KHz then started drifting.   I'll take some measurements later tonight and post what I mean.  I think it just means that the 100KHz is the ceiling for accuracy across frequency.  Ironically, its where a couple of the Fluke meters cap frequency at...

Also, my meter exhibits the same issue going from AC-DC-AC where it under-reads after going back to AC.  It has shown similar behavior when switching between modes like resistance and capacitance.  I've found myself going to off first when switching modes which is totally not cool.

[MacMeter]

The spreadsheet and video for the KT6000 have been uploaded.

FIRE & SMOKE reward when you get to the end of the video, NICE!
Some manual spec busting too.

If I'm interpreting this video and the ZT-102 video, correctly, while lacking some of the extra features, it seems the ZT-102 is overall more robust, correct?

[joeqsmith]

FIRE & SMOKE reward when you get to the end of the video, NICE!
Some manual spec busting too.

If I'm interpreting this video and the ZT-102 video, correctly, while lacking some of the extra features, it seems the ZT-102 is overall more robust, correct?

The ZT102 was damaged at 3KV.  The KT6000 was damaged at 4KV.  So no, I would not interpret the ZT102 as being more robust. 

Your interpretation may only consider the voltage modes of the two meters where I am looking for any electrical failure. 

The two Fluke videos I linked of the 87V are interesting as they don't functional test the meter between levels and they only test the one mode.  Can the 87V really survive the levels they show in during the video, clearly it depends on the test procedure.  It did very poorly in my testing because I look at all the modes and test the meters between each level.   

The Hioki was a rare exception where electrically the meter was not damaged but the plastic was starting to melt.  The meter could have done much better in the tests had the plastic insert been extended.  So I made a note of it and moved on. 

It is because of these details that I leave the videos on-line.  If someone has a question about what was done, or how a meter failed, they just need to watch the video.

[Vgkid]

These ZT/KT meter versions are rather afforable.
As a spare meter for electrical/car wirk it would either be one of these, or the more expensive am-510a.
Anyone tried the AM-500A?

[joeqsmith]

These ZT/KT meter versions are rather afforable.
As a spare meter for electrical/car wirk it would either be one of these, or the more expensive am-510a.
Anyone tried the AM-500A?

Yes, you can save a lot of money on a product by not having them certified, use glass in place of HRC fuses, use stamped connectors, leave out MOVs, don't test your software, used a single LED for your back light....  It all adds up. 

The HF free meters are very affordable as well. For garage work, why not.  Of course the new ones you can't replace the fuse, there is no back light, no beeper.....    But they are inexpensive.

[joeqsmith]

The KT6000 shunt was pretty small.  Here are the ones I had saved.

[joeqsmith]

Wow, we broke 2000 followers.  Dave mentioned that the GW121 may be a while yet.  Seems I have seen that post before so starting to look at the runner up in the poll, Gossen.  I think unlike what I did with Keysight where I bought a lower cost meter to run, I would like to buy something that I would actually want to use. 

In the mean time, I had thought about making a video just about the shunts I had saved.  Maybe take some dimensions, make some calculations and then run them.  I bet Watt loading on some of them is really bad.  And who knows what material they use.  TCs may be all over the place.  Take them to failure like I did with the meter test leads and see what we can learn from it. 

If you have any thoughts on running them, feel free to chime in. 

[Vgkid]

I look forward to the shunt shootout. Your tests look reasonable. The TC might be difficult, but it was something I have long been pondering.
That RS meter shunt looks massive, when compared to the others.

[joeqsmith]

That RS shunt is by far the largest I have seen in a handheld.  I think this video is going to be a David vs Goliath story except David looses big time.   

Metrahit looks interesting...

[Vgkid]

That RS shunt is by far the largest I have seen in a handheld.  I think this video is going to be a David vs Goliath story except David looses big time.   

Metrahit looks interesting...

It looks like it will go this way.
RS-760H/mm2000/UT61E....ZT102
This will be interesting. That ZT shunt might be good for a watt. If you measure the size/resistance, you can do some ebay shopping.

[joeqsmith]

The videos close to 30 minutes so far and I still have not damaged a shunt but not to worry.. 

[joeqsmith]

Watched Dave's reviews of the Gossen power meter.    No way I would spend over $1000 on a meter with a tacked on resistor.  Too bad, like some of the features.  Review was not too great.  Hardly turned the thing on.   

Looked at various pictures of the internals of other Gossen products.  Some look like they were made in the 90's. 

Now looking at the lower end Extra.  From the manual, they mention the KS30 for additional protection.  Search their site, nothing.   I would like to get the KS30 with it if I go this route but can't find anyone who carries it.   Time to send them an email.   

The multimeters are protected against transient overvoltages of
up to 8 kV with wave-front durations of 1.2 ms and halftimes of
50 ?s in the voltage measuring range. If longer pulse durations are
expected, for example when conducting measurements at transformers
or motors, we recommend the use of our KS30 measuring
adapter. It provides protection against transient
overvoltages of up to 6 kV with wave-front durations of 10, and
halftimes of 1000 ?s.
Continuous load capacity is 1200 VRMS. Additional influence error
caused by the KS30 measuring adapter amounts to approximately
-2%.

 

[joeqsmith]

The shunt testing is finished.  Was going to test the shunt out of the 121GW but the foam would not conduct.  And I thought it was the lowest burden meter out there.

Video should be up in the today sometime. (lack of sleep)

[Vgkid]

The shunt testing is finished.  Was going to test the shunt out of the 121GW but the foam would not conduct.  And I thought it was the lowest burden meter out there.

Video should be up in the today sometime.

I'll be looking forward to it. I saw your post, and expected to see a video.
Is is just me, or do some of those shunts look different...

[joeqsmith]

Warning, its long.  12 shunts X 5 seconds per Ampere X (100A - 3A).  Even speeding this up, it's still about 45 minutes.  I ran some checks using nichrome wire as well. 

[joeqsmith]

If all of the shunts were identical, there are still some errors in the setup.  Sensing the voltage near the supply for example adds some error, it will not vary like the temperature sensor placement or the biggest problem, inserting the shunts into the clamps. 

To give you some idea of the variance of the jig, here is the plots showing the resistance across the entire 100 Ampere sweep for all of the 5mohm shunts.

[joeqsmith]

Two of these shunts were from CEM branded meters.  They appear to have the same diameter and length so we expect these two will behave the same.   Only looking at these two, the first graph shows their resistance.  The next plot shows their voltage drop.  These two were very linear across the entire 100A sweep.   The temperatures were within 70deg C which is better than I would expect as there is a large temperature gradient across the surface.  Those clamps are a plated brass with lots of thermal mass. 

One thing I wish I had explained was Watt density.  We are looking at the power dissipated with how much surface area the part has.  The Kunsuntest ZT102 and free HF meter both calculated out to 12W/in^2.  The nichrome with even higher resistance really pushes this up and why it makes good toasters and hair dryers. Lots of heat in a very small space..