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Forum Index : Microcontroller and PC projects : Blowing up capacitors....
| Author | Message | ||||
Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9610 |
This is quite entertaining: Blowing up capacitors Smoke makes things work. When the smoke gets out, it stops! |
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Mixtel90 Guru  Joined: 05/10/2019 Location: United KingdomPosts: 7938 |
Brilliant! Now we know why those little vent areas are so important. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9610 |
Yeah, I always knew WHY they were there, but awesome to see them doing what they were designed to do.  The smaller values WITHOUT the pressure relief stampings were most impressive in ultra-slow-mo.  Smoke makes things work. When the smoke gets out, it stops! |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 5091 |
Wauw, never seen that before. Nice.... PicomiteVGA PETSCII ROBOTS |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7938 |
Makes me wonder what a *proper* capacitor would do - say 10,000uF :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9610 |
Yeah, I would LOVE to see a 10,000uF cap in slo-mo. Perhaps we should suggest it to them. Might be more like a bomb then a bang though!!! Hell, let's go to the 1F super-caps!!!!  Smoke makes things work. When the smoke gets out, it stops! |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 5091 |
That would blow away the camera. But you do not need this high speed, it goes much slower. And you need significantly more current. The variable transformer they use would simply blow the fuse. Volhout PicomiteVGA PETSCII ROBOTS |
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| Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 534 |
I used to teach at TAFE part time many years ago. After telling students to be very careful to make sure their circuits were the correct polarity, guess what , some still managed to connect electrolytic caps back the front. A few were caught in time but one student managed to leave his circuit on during morning tea, ( I think it was on purpose) and yep it exploded. We did not have a slow motion camera to record it but the room had a lot of smoke and smelt for quite a while. I often wonder what would happen if my bank of 500 Farad capacitors let go. They are in parallel with my batteries on our stand alone solar system. They work wonderfully, soaking up starting currents on induction motors really well. I did put a 250 amp fuse on them, hopefully that will catch them before they head off to bring down low orbit satellites. Pete |
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retepsnikrep Senior Member  Joined: 31/12/2007 Location: United KingdomPosts: 134 |
I love the smell of a blown electrolytic in the morning. Gen1 Honda Insights. |
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| KD5ZXG Regular Member  Joined: 21/01/2022 Location: United StatesPosts: 53 |
I wouldn't trust a single fuse of any Amperage. An entire bank discharging through the first cap or battery to fail totally bypasses such protection. Each wants a modest individual fuse to the buss that only together can pass large Amps. Edited 2022-03-11 18:06 by KD5ZXG |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7938 |
The possibility of a single device in the bank failing to a low resistance is severely scary when all the rest can discharge through it. ULP! Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9610 |
You know what is funny and somewhat ironic? I had a wireless decoder board to service today, and it was totally dead. I had replacements, so I plopped one of those in there, and powered up. BANG!  A cap on the PSU input was installed back-to-front, and so it blew it's top just like those in the videos.  Quite a shock though, physically. They do make quite an impressive "POP!" when they go if you are not expecting it!!! Smoke makes things work. When the smoke gets out, it stops! |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 4044 |
Wow - good catch! John |
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| Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 534 |
I am not sure how the capacitors are connected as they came in two 12 volt banks They are shrink wrapped and have some sort of balancing circuitry on them. I guess I could put a fuse between the two series banks as well. But taking the packs of series connected caps apart would not be easy. Originally the capacitor banks are used to start trains. I will have a look again at them and see if there is a way to add more protection. Any suggestions welcome Pete |
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| Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 534 |
I just had a look online at the banks I have, they are 16 volt banks and I have two of them as my system is 24 volt. There is a youtube video by an electrical engineer on safety of them, so I will look at it. Some of the installations on youtube look far scarier than mine. Still I would like to make sure that the system is safe. Thanks for jogging the thinking bones Pete |
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