Poll

How many cycles will the KeySight U1281A's detent spring last?

0-2000
7 (17.9%)
2k-4k
5 (12.8%)
4k-8k
14 (35.9%)
8k-16k
7 (17.9%)
>16k (most rubust meter ever made)
6 (15.4%)

Total Members Voted: 36

Author Topic: Handheld meter robustness testing  (Read 1149921 times)

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Offline IanB

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Re: Handheld meter electrical robustness testing.
« Reply #2100 on: November 21, 2017, 12:09:21 am »
Did you ever ask yourself why the bar on an electric train's overhead contact system doesn't wear out in a couple of days?

That's actually complicated, and there have been evolving designs for contact materials and other factors to improve performance.

One key element is that the overhead wire sweeps from side to side and does not have a single contact patch on the pantograph.
 

Offline kcbrown

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Re: Handheld meter electrical robustness testing.
« Reply #2101 on: November 21, 2017, 04:47:34 am »
You, sir, have WAY too much cool gear, and I'm insanely jealous.  :-DD

Seriously though you've gotta show some of this off in a video.  How else can you justify it?   :-D



Sent from my iPhone using Tapatalk
 

Offline floobydust

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Re: Handheld meter electrical robustness testing.
« Reply #2102 on: November 21, 2017, 05:41:15 am »
Did you ever ask yourself why the bar on an electric train's overhead contact system doesn't wear out in a couple of days?
It's the same reason the rotary switch contact does. :popcorn:

Electric train's pantograph uses carbon strips, softer than copper- like in a brushed DC motor commutator. But I see your point about the physics.

Thickness of the PCB copper compared with the wiper metal, I thought around 1/10 and thinner would lose. The wear model says it's hardness and force.
Another factor I notice is switch diameter makes the far outside (ring) path longer so the inner rings (wipers) don't wear as much.

Just looking at it to see why the cheap meters rotary switches did poorly. They have to redesign their wiper, less force it seems.
 

Online Fungus

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Re: Handheld meter electrical robustness testing.
« Reply #2103 on: November 21, 2017, 06:36:16 am »
Actually, since I am horribly bored in the cleanroom waiting for the vacuum press and laser to do their job, I'll disassemble a DT-830 and put the PCB under the profilometer  >:D

That would be an easy test.  Let's see what you came up with.

I'm wondering if the problem is in the wipers, not the PCB traces. When the wiper starts to look like this it makes sense (to me) that it will wear out the PCB/traces much faster.



And as noted, the wear on the PCB/traces is spread out over the entire turn of the dial. It's a lot less than the concentrated 100% wear on the wiper.
 

Online Fungus

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Re: Handheld meter electrical robustness testing.
« Reply #2104 on: November 21, 2017, 06:39:45 am »
Electric train's pantograph uses carbon strips, softer than copper

"Pantograph". That's the word I couldn't remember...  :-DD


One key element is that the overhead wire sweeps from side to side and does not have a single contact patch on the pantograph.

Spoiler!

I wonder if they could to the same with rotary switch traces on PCBs. It would look pretty if they weaved from side to side.
« Last Edit: November 21, 2017, 09:14:09 am by Fungus »
 

Offline HalFET

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Re: Handheld meter electrical robustness testing.
« Reply #2105 on: November 21, 2017, 07:50:29 am »
Actually, since I am horribly bored in the cleanroom waiting for the vacuum press and laser to do their job, I'll disassemble a DT-830 and put the PCB under the profilometer  >:D

That would be an easy test.  Let's see what you came up with.

Forgot the DT830 at home, but we have a whoooole pile of Uni-T 61Es :D
 

Offline floobydust

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Re: Handheld meter electrical robustness testing.
« Reply #2106 on: November 21, 2017, 10:02:27 pm »
The contact pressure (force/area) is probably the thing to look at.
You'd have to estimate the contact (wiper) area and its cantilever spring force. Maybe a phono cartridge tracking force gauge or the drug dealer special (scale) would explain the high wear.

Checked and my AN8008 has all copper wipers, no steel. Not sure if annealed or hardened.
 

Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #2107 on: November 21, 2017, 10:56:44 pm »
The contact pressure (force/area) is probably the thing to look at.

Right because the obviouse hole in the middle of the pad couldn't have anything to do with it.

Offline HalFET

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Re: Handheld meter electrical robustness testing.
« Reply #2108 on: November 21, 2017, 10:59:40 pm »
Someone was using it for proper work so couldn't exactly kick them of it to do my measurement. But I'll just do it on Thursday then, for now you can pick which DT-830 I should let suffer.  ;D

A few side notes: The black one on the left seems to kind of work as intended and has the best build quality. The yellow and crappy blue one have unfinished soldering on the transistor tester, and I had to open up the miniature ANENG to losen the tension on the PCB so I could operate the rotary switch.
 

Offline kalel

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Re: Handheld meter electrical robustness testing.
« Reply #2109 on: November 21, 2017, 11:31:31 pm »
The left one is the "upgraded" temperature model. The best version I think (functionality, otherwise the small version looks great, such a small size). I don't have one and can't say about the inside.
« Last Edit: November 21, 2017, 11:35:53 pm by kalel »
 

Offline stj

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Re: Handheld meter electrical robustness testing.
« Reply #2110 on: November 21, 2017, 11:49:41 pm »
the yellow one should suffer, i hate that colour.
it always makes me think of telephone engineers!!
 

Offline Cliff Matthews

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Re: Handheld meter electrical robustness testing.
« Reply #2111 on: November 22, 2017, 01:34:02 am »
Joe, I just noticed something..
As per the poll atop the thread (and doubled sub's), maybe we're gonna be need a holiday custom BBQ and Fireworks?

I for one would like to see if a lightly smoked Fluke 10 or 12 would ruffle those YouTube button pushers  :-DMM
 

Offline rsjsouza

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Re: Handheld meter electrical robustness testing.
« Reply #2112 on: November 22, 2017, 02:42:43 am »
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 IanB

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Re: Handheld meter electrical robustness testing.
« Reply #2113 on: November 22, 2017, 02:52:05 am »
Wife says no on this one.

But delivered in 15-25 working days!
 

Offline Cliff Matthews

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Re: Handheld meter electrical robustness testing.
« Reply #2114 on: November 22, 2017, 03:23:10 am »
Wife says no on this one.

But delivered in 15-25 working days!
Too fast, the models in my day took 9 months!

Why would they supply 10 amp leads if it only can do 600ma?
« Last Edit: November 22, 2017, 03:50:19 am by Cliff Matthews »
 

Offline xrunner

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I told my friends I could teach them to be funny, but they all just laughed at me.
 



Online Fungus

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Re: Handheld meter electrical robustness testing.
« Reply #2118 on: November 22, 2017, 06:57:54 pm »
Why would they supply 10 amp leads if it only can do 600ma?

Simple: Because they want the Ohms measurements to be super accurate.
 

Online HKJ

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Re: Handheld meter electrical robustness testing.
« Reply #2119 on: November 22, 2017, 07:04:02 pm »
Why would they supply 10 amp leads if it only can do 600ma?

Simple: Because they want the Ohms measurements to be super accurate.

How would printing 10A on the probe help with that? Even probes with fairly thin wires has the 10A stamp on them.

The resistance in probes usual below 0.1ohm each (Down to 0.03ohm for good probes), i.e. it do not have much influence on the ohm range.
 

Online Fungus

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Re: Handheld meter electrical robustness testing.
« Reply #2120 on: November 22, 2017, 08:11:02 pm »
The resistance in probes usual below 0.1ohm each (Down to 0.03ohm for good probes), i.e. it do not have much influence on the ohm range.

Not if it was a "600mA" probe.  :popcorn:

 

Offline Cliff Matthews

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Re: Handheld meter electrical robustness testing.
« Reply #2121 on: November 22, 2017, 08:48:57 pm »
The resistance in probes usual below 0.1ohm each (Down to 0.03ohm for good probes), i.e. it do not have much influence on the ohm range.

Not if it was a "600mA" probe.  :popcorn:
Things hide in plain sight  :palm: those probes looked familiar (same shorty's that came with my Aneng 8002).
 

Online HKJ

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Re: Handheld meter electrical robustness testing.
« Reply #2122 on: November 22, 2017, 08:54:54 pm »
Things hide in plain sight  :palm: those probes looked familiar (same shorty's that came with my Aneng 8002).

The Aneng probes are about 0.06ohm each.
 
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Offline stj

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Re: Handheld meter electrical robustness testing.
« Reply #2123 on: November 22, 2017, 10:34:42 pm »
Things hide in plain sight  :palm: those probes looked familiar (same shorty's that came with my Aneng 8002).

they arent like the ones that came with mine.

 

Offline joeqsmithTopic starter

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Re: Handheld meter electrical robustness testing.
« Reply #2124 on: November 22, 2017, 10:49:13 pm »
Why would they supply 10 amp leads if it only can do 600ma?

Simple: Because they want the Ohms measurements to be super accurate.

How would printing 10A on the probe help with that? Even probes with fairly thin wires has the 10A stamp on them.

The resistance in probes usual below 0.1ohm each (Down to 0.03ohm for good probes), i.e. it do not have much influence on the ohm range.
This all seems to be true.

Here I am attempting to put 10A through various probes.  Note that the two 830s never made it up this high.



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