Mr. Joules - when things fail catastrophically ;)

[randomtronic]

Hi All,

I made this contraption here:

to test in a repeatable way what happens to grossly overloaded components.
Here is a 20mm glass fuse getting annihilated:

And for a comparison, uneventful selection of BS1362 fuses (HRC) which do their job:


I am planning to test and observe more things, some out of curiosity and some out of anger , as time goes on.

What do you guys think of my contraption?

[Spuddevans]

What do you guys think of my contraption?

I think it is very interesting. Thanks for sharing those. Post up some more when you make them.

Tim

[mmagin]

Nice wood prototyping! Interesting how even the fine copper wire blows the door open.

[Ian.M]

As the caps aren't rated for pulse discharge applications you can expect them to puke their guts, develop excessive leakage or go Hi-Z sooner or later.  Some way of monitoring the charging current would be useful so you can detect leakage.   Also I would prefer it if it had perspex safety screens (with a hole for the 'idiot stick') either side of each of the clothespeg contactors, and a few more interlocks e.g. solonoid on the mechanical trigger mechanism so it cant be reset with power on, and a door switch on the test compartment lid that disconnects power and switches in a rapid discharge resistor.

N.B Perspex/Acrylic can shatter - the test compartment lid should be Polycarbonate.

[randomtronic]

As the caps aren't rated for pulse discharge applications you can expect them to puke their guts, develop excessive leakage or go Hi-Z sooner or later.  Some way of monitoring the charging current would be useful so you can detect leakage.   Also I would prefer it if it had perspex safety screens (with a hole for the 'idiot stick') either side of each of the clothespeg contactors, and a few more interlocks e.g. solonoid on the mechanical trigger mechanism so it cant be reset with power on, and a door switch on the test compartment lid that disconnects power and switches in a rapid discharge resistor.

N.B Perspex/Acrylic can shatter - the test compartment lid should be Polycarbonate.

Thanks. You are right in what you are saying about interlocks and polycarbonate. I will upgrade this at some point, this was just what I had around. For the time being, I am being aware of the risks, and when I trigger it, I am wearing safety glasses and looking AWAY from it, in opposite direction (It is too scary to look at it  ) Then I review what happened through camera footage.

The caps are definitely not rated for this, I know. But all of them are salvaged filter caps from teardowns, so when they do go, I can just replace them. Those are a bit like consumables here... Leakage can be noticed somewhat by observing the rate of discharge when not engaged, I think, so when it begins to drop quickly, I should know that some caps are busted

[Gyro]

An excellent demonstration. (Though I agree with the advice about improvements for your personal safety). Using Photoflash capacitors would be a potential improvement but unfortunately they are only normally rated to 330V.

I've been wanting to do a DC test on a BS1362 fuse for a while. I have a DMM which will only accept a 1 inch fuse on its lower current Amps ranges, so none of the standard SIBA ones will fit. I have a BS1362 1A fuse fitted but have always been a little concerned about how good its DC performance would be, so thank you.

[Ian.M]

Add a 1N5913 3.3V 3W Zener in series with the charging circuit output, between the voltmeter and the cap bank, with a 30mA red LED + a 100R series resistor across the Zener and you'd have a pretty good indication whether or not charging is complete i.e. if the caps are going leaky.   You might need to fiddle with a parallel resistor to allow a little leakage before the LED turns on.

To detect if the caps are going bad you really need some way of instrumenting the discharge.  Possibly a 10:1 attenuator for voltage across the  D.U.T. cap bank and a high ratio current transformer made on a split ferrite core with a single turn primary and 100 turns of magnet wire into a 0.1 ohm burden resistor, then you could hook it up to a DSO in single shot mode and do some waveform maths to get the discharge energy.

Edit: due to the two pole contactor, you cant safely scope the voltage across the DUT, even attenuated 10:1 without a high voltage high bandwidth differential probe, which will be $EXPEN$IVE.

[Neilm]

In addition to your comments on glass fuse hazards, probing the mains could mean the plasma on the arc continuing to conduct for many cycles increasing the energy in the explosion.

IEC61010 (the safety standard for meters) explicitally states that if you can mis-connect any leads for several functions all misconnections must be tested. It is to guard against the very thing. I have tested a very cheap multi-meter on this exact test. It blew the 50A breaker on the input to the lab and we found bits of the case scattered all over the lab.

[Marco]

As the caps aren't rated for pulse discharge applications you can expect them to puke their guts, develop excessive leakage or go Hi-Z sooner or later.

Could you give some evidence or anecdotes to back this up?

[Muttley Snickers]

Well done, I like this stuff but as others have already mentioned perhaps some of the safety aspects could be improved upon particularly with all types of people viewing these videos, qualified and experienced people should know better in regards to risk and safety but some younger or newer viewers may not see all the potential dangers.   

I'm not sure if you are taking requests but could you also run a standard M205 glass fuse or similar with a free fitting heat shrink sleeve over it just for comparison against the one you previously did where the blast was not contained, I have a habit of doing this in some of my own equipment or gear that I have made which is mainly lower voltage stuff and generally pretty safe anyhow.   

Also I found this video the other day where it appears that some manufacturers are opting to do away with fuses altogether, I suspect they may have viewed your earlier exploding video and probably thought it was safer for the user, good on them for caring so much.   

[joeqsmith]

You have built a bit of a death trap. 

It's a bit addictive isn't it?

You may want to consider adding some sort of output network that will control the rise time, source impedance and the decay.  With the line being AC, you may want to set it for something less than a half or quarter cycle.

A faster camera would be a good addition.   You may be interested in one of these:
https://www.kickstarter.com/projects/1714585446/chronos-14-high-speed-camera

I offered to buy one of the initial prototypes before I knew his intent for them.  I never saw anyone attempt to capture an arch like you are showing and I have my doubts it would be fast enough so I did not join the kick start.   

The following clip shows some of my tests.  Normally, I can only supply up to about 20J.   


Have fun and be safe!

[mtdoc]

What do you guys think of my contraption?

I like it. Well done.

Looking forward to seeing more videos.

[randomtronic]

Thanks Everybody for the replies!

joeqsmith: Yes, there is this satisfying feeling... And yes, I would absolutely love to shoot this with Chronos. Unfortunately, even as inexpensive as it is for a high speed camera, it is out of my hobby budget by an order of magnitude 
 
I like the idea of interlock on the lid, and the lid stronger a bit - I will most likely get this done soon. It is annoying having to fully discharge it when there is charge remaining, I think I can use small halogen bulb as a rapid high power discharge resistor ( I have some laying around)

Muttley Snickers: Yes, I am open for suggestions on what to feed to Mr. Joules Heat shrink covered fuse sounds interesting - I will definitely get this one done.

For anyone interested in more videos like this - Yes, there will definitely be more. I started my YT channel about a year ago, and went through all stages from unwatchable to somewhat OK (I think  ) videos in that period of time. I find YT motivates me to do something interesting just so I can upload a new video. Before I started the channel I just sat on my behind procrastinating. So, please feel invited to subscribe to my channel to see more of my random videos (always electronics related)  and help with my motivation

And please drop in some suggestions what you would like to see in next Mr. Joules videos.

Thanks again for the warm welcome 

[joeqsmith]

That Sony I show was a big step up but no where near fast enough.  Stick with what you have for now. 

I normally test with no cover but you are playing with glass and any time I do that, I cover the thing up.  The  big difference is you trigger yours with your hand.  Mine is off a timer and I am no where near it when I play with the higher energy transients.  I also have a long discharge probe with around a 6K resistor and an LED that I stick on the lines and across the generator before I do anything.  The system is fairly safe in that it turns off the outputs but just in case.....

For the discharge, I am using resistors.  I have some small bleeders, 100M or so but the ones that control the discharge are pretty small in ohms.   The last image in that video I show was a small 40W bulb.  If you try a halogen bulb, make sure you cover that thing up before your try it! 

The one thing that sparked my interest in your video is that longer glass fuse you show.  When it blew, there was a green glow.   You see that same green glow at about 1:35 seconds on mine.  This was the fuse that was in a VC99 meter, sitting in the meter...   

Some things I have thought about running are:
See how many times I have to hit a MOV before it fails.
Add a PTC in series with the same MOV and see how many times I have to hit it before it fails. 
Compare some caps that are rated for the AC mains compared with ones that are not.
Many people post about counterfeit fuses and I have asked for a reputable counterfeiter so I could run their parts.. 

PhotonicInduction has taken out all sorts of things with that large capacitor of his.   That's way out of my league!! 

[MacMeter]

"I have asked for a reputable counterfeiter". Sorry, but this made me laugh! I know your intent, and love your well thought out videos!

The subject of counterfeits and clones is a sore spot for me and I assume lots of consumers, and is basically out of control! For some products, it may just be the loss of your money, in cases of safety fuses, it's downright sinister and of course DANGEROUS. It would of course be welcome if there was a reputable source to BUST all the FAKE fuses on EBay, Amazon etc. but that would most likely be a full time job for a staff of people to attempt. And while it's not just the Chinese, though they may be the king of this sort of unsafe money grabbing, it has become an epidemic.

Here's my little example. I know very little about electronics, but like many, I've used multimeters since I was a kid. I never thought much about their safety and internal fuses. Just recently I did a lot of homework on buying my very first decent MM. (I've used others Flukes etc. over the years). I opted for the EEVBlog BM235, and simply want to buy a few spare fuses, the original ones speced and used in the meter. Being a decent online shopper, I then found myself going down the rabbit hole. Prices for original fuses between $5-$45. Send up the RED FLAG! Hmmm, reputable sources, top dollar, EBay and some Amazon sources, bottom end prices. That price swing alone, made me realize that there is enough of a profit margin to be made, that the FAKES are most likely the reason. That alone makes buying QUALITY fuses more of a potentially dangerous proposition then it should ever be.

I don't know if there is currently a viable solution to this problem, it would be a great fantasy to see all these counterfeit products being busted and outlawed, but that's just a dream, it seems.

[nixfu]

This sort of thing just cries out for a real slow motion camera I think.  That would be fun.

[bktemp]

This sort of thing just cries out for a real slow motion camera I think.  That would be fun.

You could ask Dave to give it a try using the Chronos camera:
https://www.eevblog.com/forum/blog/eevblog-947-chronos-high-speed-camera-review/
21000fps (or 38000fps when the new firmware is ready) should be fast enough to make some nice videos. From my experiments the action happens in about 3ms for 6x32mm fuses and up to 25ms for 5x20mm fuses using 1500uF @ 350V.  That should give at least 50 useful frames. The exposure could be a problem, because the initial arc inside 5x20mm fuses is extremely bright, saturating the first couple of frames. 6x32mm fuses are less violent.

[f4eru]

Hello,

When you say :

fuses are put in circuits to prevent users to have electric shocks

That's incorrect. The purpose of fuses is to prevent fire.
To protect against electric shock, you need an RCD.

Also, exploding fuses are not necessarily "bad fuses".
Each fuse has a rating of rupture capacity, and in most application, this rating can be quite low.
Explosion is not a problem if the fuse is embedded inside an equipment and this enclosure contains the explosion.

[randomtronic]

Hi All,

Thanks for all advice. I have upgraded Mr. Joules to v1.1

I liked the idea of having interlock on the door - it is now in place, all it took was a micro switch and a relay. Now when the flap is open, a 30W halogen bulb is connected to cap bank for quick discharge, and at the same time power coming to HV generator  is cut off. When I close the lid, bulb disconnects, and power connects to HV gen.

The lid also has changed, not polycarbonate (don't have any... ) but I got some 4mm thick acrylic - i think it will do the job, but i still am cautious with this.

Here is the update on Mr. Joules v1.1:


And here, just for fun, is Intel Core i5 inside Mr. Joules

[chickenHeadKnob]

Mistah Randomtronic I have a request. Please do a follow-up test of a glass fuse (m205 20x5mm) type inside one of those cheap ebay panel mount fuse holders like:

http://www.ebay.ca/itm/New-Screw-Cap-Panel-Mount-Fuse-Holder-For-M205-5x20mm-Glass-Tube-Fuses-Case-/400736510659?hash=item5d4dc1e2c3:g:AEgAAOSwFAZTtLlB

To see if the blast containment is adequate. Also test of other styles of enclosed fuse holders would be appreciated, if you are looking for righteous things to blow up.

On a personal note, I am trying to place your accent. It is as if a viking child washed up on the shores of East Anglia and was raised by local sheep shaggers punters ***.
The not knowing your back story is driving me crazy!

***What? - it could happen

[randomtronic]

Hi chickenHeadKnob. You made me laugh lol, no, i am not a viking, although you are not the first person suggesting this (maybe I should check my family tree?)
Have a look here:
https://www.eevblog.com/forum/chat/new-member-please-introduce-yourself/msg1022340/#msg1022340

[randomtronic]

Mistah Randomtronic I have a request. Please do a follow-up test of a glass fuse (m205 20x5mm) type inside one of those cheap ebay panel mount fuse holders like:

http://www.ebay.ca/itm/New-Screw-Cap-Panel-Mount-Fuse-Holder-For-M205-5x20mm-Glass-Tube-Fuses-Case-/400736510659?hash=item5d4dc1e2c3:g:AEgAAOSwFAZTtLlB

To see if the blast containment is adequate. Also test of other styles of enclosed fuse holders would be appreciated, if you are looking for righteous things to blow up.

On a personal note, I am trying to place your accent. It is as if a viking child washed up on the shores of East Anglia and was raised by local sheep shaggers punters ***.
The not knowing your back story is driving me crazy!

***What? - it could happen

I just ordered a bunch of those holders and some other ones with a couple boxes of fuses.
I will post a video once this arrives

[joeqsmith]

I would think in most cases where a fuse holder like this is used there is some sort of current limit in line with it.  The fuse may not see a direct hit like it would for example with 10 ampere shunt like in a multimeter.   Would a brand name fuse holder like the one shown with a glass fuse survive? 

[joeqsmith]

In the video where you run the 30mm 1A 250V fuse, I was not sure if that was a 3AG, fast or slow?  I picked up some 20mm and 3AG fuses. Both fast and slow blow.  Both 1A 250V.  UL and CSA approved name brand.   Also a name brand holder.  Thought it would be interesting to compare results. 

[randomtronic]

The big fuse was fast blow. I think thats why it worked ok. So far from my observations, the worst thing to put in multimeter is 20mm slow/time delay fuse. Guaranteed explosion I am waiting for more variety to arrive and will pop some more fuses. For the time being I am blowing up random stuff
Btw. I was wondering if to post more exploding components here, what do you think? Maybe a separate thread, because its not only fuses, but still satisfying to watch