Failed elevator switch fuse / fusible disconnect
ฝัง
- เผยแพร่เมื่อ 15 มี.ค. 2021
- This is a common industrial grade switch-fuse unit used for isolation and protection. The unit in this video had failed, so I thought it would be interesting to see what had gone wrong.
Note that the failed module also had a loose bit of plastic in it, and that may have contributed to the unusual failure.
The contacts are notable for having a ball joint effect at one end, which ensures they always sit flat on the other contact. The spring loaded mechanism is basically two very powerful springs acting as an over centre toggle which will snap open and closed with force, rotating the common switch operation bar.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
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This also keeps the channel independent of TH-cam's advertising algorithms allowing it to be a bit more dangerous and naughty. - วิทยาศาสตร์และเทคโนโลยี
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Regarding skipping or speeding up the video, I personally like to see the whole messy gutting process in detail from beginning to end, including what mistakes not to make and learning old and new methods of how things are put together (helps spot potential embarrassment when taking other things to bits). Your videos are always informative or fun or both.
Yes! This is an essential part of Clive videos for me!
The main reason I watch these videos is to watch a Scotsman slowly and methodically break things in new and unique ways
Yeah for sure one of the reasons I enjoy this channel so much is the satisfying destruction in between learning things about electronics engineering.
The fuse may have failed but that means the elevator won’t let you down!
Let's go crazy
Let's get nuts
Look for the purple banana
'Til they put us in the truck, let's go!
I endorse this message! Haha
Yeah but you can't get it up either
Mind of a Evil Genious😂 Ha ha ha haaaaarh, First I shall take over my Town....Then the World......Har har harrrrr harrrrrrrrh
@@daviddavidson2357 who told you ffs?🤔😳🤪🤪
One thing I've learned, through the unauthorized puncture of my skin from spring loaded bits, is that if you are worried about a spring, first loosen all the screws, and if it's pushing back, stop right there and reassess
Usual trick. Then take one screw out, see how long it is before it's out of the thread so you know how long the rest can come out before they let go. One of the problems can be that the nasty spring is in a loose component - so you don't find it pushing outwards - but then a loose bit inside explodes when you least expect it.
No! Best way is, have someone else do it... :)
Spoken like a garage door replacement person? Those counter-balance torsion springs will happily remove limbs.
@@R.Daneel I just turned 16 on the 12th of april, living in the US I can only legally hold a permanent job now that I'm 16. But I have worked with those springs before and they're scary. I used a magnetic decelerator my uncle gave me (he used to be a roofer and to be osha compliant, you need one) and essentially crossed my fingers and let the spring go attached to that thing. There shouldn't have be much tension on it but the guy that installed was apparently a moron, because when the door was open it'd be under tension and without the garage door opener it'd pull the door about two inches (about 5cm) off the ground
@@R.Daneel I have seriously thought about those as an energy source for starting car engines without electricity. Any multi-wind springs - like on recoil engine starters and tape measures have amazing abilities to spring totally uncontrollably if not securely controlled !
Impressive detective work!
Also I felt so proud when I figured out the arc quenching before he said it aloud.
These vids are like ASMR to me… the voice, the little noises, the clicking and clunking the pauses for thought…. Ahhhhh lovely!
"This spring was made for pingin, and that's just what it'll do... This spring is gonna ping all over you"
No friend, you forgot _One of these days._ But don't edit your comment or you lose the heart.
Many years ago I enjoyed the first Jerasic Park movie. Some years later I went to work at my first maintenance job. I never knew the most realistic thing about that movie was the breakers (disconnects/fuse switch) that you have to pump to restart.
Ha ha ha, great observation. Only a Techie could notice summit like that?😂
Really true! It's common to see spring loaded breakers where you do need to manually load up the spring or the brake has a solenoid/motor to do it.
The most surprising thing for me is that one they used in the movie (Westinghouse SPB-100) was truly expensive (tens of thousands of dollars) yet they still somehow managed to get it into the film, rather than opting for something cheaper mocked up to look fancy - no expense spared I guess. Given my love of electronics and electrics it's one of my favourite parts of the movie.
@@Berkeloid0 Very likely they just borrowed it from the studio maintenance department, as the power demand for a film set is big enough to have power systems more in size for a large industrial area, in an otherwise small space. Easy to pull an entire cabinet from an unused set for this, or even film in situ and cut in the scene later as well, and use a spare in the set for scenes where it is only there for view.
I haven't heard of a "Jerasic Park" movie. Is it anything like Jurassic Park?
Excellent deductive reasoning. The best days at work are figuring out why something failed, but it is also someone else's problem to put it back together.
Clive, you say on your first day in the steel works you were installing slate switch gear, you started work in the "Stone Age"!
That would be large slate slabs used as and insulated panel to mount live contacts and conductors... fully exposed contacts and stuff like knife isolation switches. This was used before plastic and composite panes [stuff contains a asbestos and mineral dust bonded with stinky tar like compound] were developed.
The marble panes I've encountered must have been an 'up market' version of the open stone faced boards - Zero IP rating - NO isolation factor! High danger factor!
At least the marble was a pretty white colour and not a nasty grey.
Bit of a bugga to have to install a new switch or cutout for a meter on the old stone panels... but I seemed to get all the 'good' unique jobs that turned up.
"Bear with me" No, Clive. The bear is with us. 😂
😂
Or beer?
Fur-rocious.
12:20 when he takes off his gloves to work with his bear hands. (These jokes write themselves.)
@@Gameboygenius Yes, they do!
A very sound theory as to why it failed. Brilliant find! Noticing the sand and the potential source of the sand, then what effects said sand would create within an operating unit. How many people would have even seen the sand and realized it was from a broken capacitor, then concluded it was the potential cause of spring failure? Only the Big Clive, that's who!
I helped build a power distribution cabinet for the Albert Hall. Huge thing that needed to be curved and modular to fit it into the switch room. Had many units like that. 2x👍
They don’t explode when being taken apart. They can however undergo ‘uncontrolled rapid disassembly”
Or like SpaceEx, unscheduled, non-commanded self disassembly?!
I love that term. I'm stealing it.
@@whitesapphire5865 - Maybe it blew the lithium battery pack :-)
I’ve had my share of those lol
Pause the video? No way. The narrative during disassembly is always entertaining, especially with the r-r-r-risk of impalement!
HRC fuses were THE best safety improvement over the old domestic rewireable ceramic carriers. Removed the temptation to replace the blown fuse wire with random paperclips (my Grandfather's speciality!) I've got 50A DIIN HRC carriers in both banks of our home distribution board, as a "last ditch protection" strategy should any fault current exceed the (already good) breaking capacities of our RCBOs. If the fault current exceeds the 80kA break capacity of the HRC elements, I think that'll be the least of our problems! :-)
I've never measured a Ze value low enough to cause a fault current more than about 3 kA. I poke my test meter into mainly single-phase supplies in the suburbs of a large UK city, but occasionally 3-phase supplies as well. I've never had to specify circuit breakers with more than the standard 6 kA breaking capacity.
I think even the old BS 3036 semi-enclosed fuses are good for 3 kA as long as there's a suitable cut-out fuse upstream - there's a table in BS 7671 somewhere.
I've seen big HRC switch-fuses in circuits where maximum fault current is 1 or 2 kA, and never understood why a little MCB wouldn't have sufficed.
@@westinthewest The only situation where such a high prospective fault current might arise would be from a significant supply over-voltage, and that's all but impossible (even in rural Australia). It is always impressive how an 18mm wide MCB can handle many kA of fault current, and sometimes they survive (i.e. can be reused until a replacement arrives!)
I really appreciate your videos. I've been binge watching them for the last couple of weeks and am completely fascinated by your knowledge, so much so that I bought a soldering kit, have made a lamp, modified some LED bulbs, and have a nixie tube clock kit on order. Thank you for what you do!
I barely understand most of what you talk about but your troubleshooting abilities are second to none. You have so much experience in electrical work its just mesmerizing to watch you diagnose an issue and find the problem with such high levels of accuracy. Bravo mate!
As a young whipper-snapper I can say that the olds stuff was more robust, reliable, and easier to maintain on average from engines to electronics. They designed it that way. The new stuff is generally computer controlled, complicated, uses specialized tools bought from the manufacturer to assemble or disassemble, made from replaceable assemblies, more efficient, and designed to be replaced by a dealer tech only or to be thrown away so you buy a new one.
I'm very thankful that Clive makes these videos covering the more industrial side of things. I didn't realise how much it would help me with my current job back when I was watching when I was 16. As someone who writes operating and maintenance manuals its nice to understand things on a component level :)
In all the years i have been repairing stuff,i still get a buzz of achieving it (no pun intended) like my mate Vince does,even though i'm a computer technician.
I really really enjoy the way your brain diagnoses electronic issues Clive. I am not a electrician in any way, shape or form - I'm a student studying Conservation and Environmental Management. The way you look at electronics is the way I look at ecosystems - trying to trace back to that one part that stopped working. Your videos inspire me to think differently about things, being on the spectrum it's easy for me to "A+B must = C". So thank you for sharing your process mate, it's a fine art my friend. 👍🧠
_"Mofo spring"_
Ahh the technical term! XD
Nice to end the day with the soothing sounds of Big Clive's voice
I always thought an audiobook - even of poetry - would make a soothing "after a long day of work" relaxation system.
Now I want mikeselectricsstuff to blow an HRC fuse with an enormous overcurrent and see if it really doesn't blow up. Would probably be quite anticlimactic, but interesting nonetheless.
That's like sand in your shorts at the beach. 🤣
Chaffage.
Natural exfoliation, nowt bad about that shizzle. Part of the The lazy man's grooming routine...my type of easy lifestyle choice....
@@bigclivedotcom Good Chaffage...There's cream for it anyway, so no issues there.🤔😁
Speaking of Phase Failure relays... I remember once working in a hospital doing an 'on load generator test'. The generator failed and we attempted to switch back to mains. It was subsequently discovered after 20 mins of darkness that the Phase Failure relay had, well, failed. Cue linking the contacts out on that unit and a planned shutdown later on that day after finding a like for like replacement in the stores!
My Great Grandfather worked maintenance at a mineral plant, and he used to carry 3 pieces of copper pipe the same size as the fuses they used in their bus bar disconnects. If they blew a fuse and didn't know where the fault was, they would replace the fuses with the copper pipes, close the disconnect and look for the smoke. Safety 3rd really was the motto back then.
I may possibly have used a similar technique in the past, but you have to be careful about causing cable damage.
"I don't know if they changed terminology since, they do that quite a lot"
Well, at least basic components like condensers won't change.
Wait...
or someone felt sorry for the poor thing knowing it was going to spend it's days locked in an enclosure far from light and air . . . so they took it for a day at the beach.
Oh boy when Clive breaks out the gloves you know it's serious
All I know about electricity is enough to be dangerous lol. I wish you did a video for unknowing people about how to use a multimeter without burning it up. I'm not always sure what to set it on. I'll never forget your video on shaving with a funnel.
don't worry, some of us have been using meters for many years since childhood and still blow them up on occasion. I've sent plenty to meter heaven over the years, including vacuum tube models, which I still own some of.
As for the sand, a very common cause for failure is people drilling in walls over electrical cabinets that dont have good ingress protection. Cable ducts/conduits also can blow dust into cabinets due to pressure difference between rooms, which is why it is prefered to have the conduit end before the cabinet and use a cable gland on the individual cables.
Fucking people drilling the entire walls in the house
@@SpeedsGamer Isn't that more like 'demolition' than 'drilling'?
Yeah, and less skilled electricians drilling holes in cabinets with nothing to protect against swarf going into terminals and switch mode power supplies.
@@westinthewest sometimes it sounds like it!
@@bigclivedotcom I have had a few contactors that mysteriously had one pole not make contact anymore, even though they looked fine, just a tad dusty. Under the microscope, there were hard (probably quartz) particles pressed into the soft contact material, keeping the contacts apart far enough not to touch anymore. With 400V and large rounded contacts, it takes surprisingly little not to arc over. Root cause was quite evident, last time some contractors ran pipes above the control cabinets, and didnt bother with a vacuum cleaner or anything while drilling holes to anchor the pipes, and the cabinet had missing and ill-fitting cable glands on the top.
My general rule at work is never throw away anything mechanical/ electrical without taking it apart first. I started to do this as a kid.
My brother in law's favourite saying; If it's not broke, don't fix it.
I was at an event helping with sound and they brought in their own homemade distro which required manual tie and a 40 amp two pole breaker. Apparently it wasn't working right and they had to get a new one prior to me getting there. At the end of the day when they uninstalled everything they were going to throw away the bad breaker and we're wondering how it worked and what might be wrong with it, I'm like no way I'll take that and said I have taken apart a single pole breakers but not a double pole that thing will be apart faster than....
curiosity and thirst for knowledge. it's still the best way to learn many things or the fallacy of them ;)
There's a lot of little subtleties in that switch design that I think you're overlooking. If you notice the center hub actually turns a little bit past the center line so it's actually has a toggle action. There is a spring resistance when you twist it back that it you have to overcome before you break the circuit.
The other interesting thing is that it is obviously designed to apply direct force to breaking contact. The pressure applied to the contacts to make contact is limited by that spring, but you've got a direct mechanical linkage that goes from the contact to that arm to the hub and then out the side to the switch lever that allows you to apply great force to make that thing separate. Usually contacts just get separated by a little spring, there's not that sort of direct mechanical means to apply force.
Yes, over centre lever action.
You don't understand that the main priority with that action is to OPEN the contacts as fast as possible... using that snap action.
Closing is much less an issue - make .. not a break that creates and arc.
These are made to open or close under 'on load' conditions, so that fast snap action is needed.
Same principle in home light switches... why they should click.... and why the higher amp rated ones click louder.
These thump open and closed.
this is what Anakin was talking about when he said he doesn't like sand
Turned him into a right little devil
My 1st and only 'spring burnout' was replacing a fuse with a Biro spring when 11yrs old in '64 for my mains Philco valve radio, Then picking it up with the cardboard base not attached. Things that stick in ones mind....9V transistor radios where a god send.
A possible durability upgrade would be to use an nylon leaf/wishbone spring, or spring with insulation at one end so it cannot be the electrical connection. Then if something like that happens, the assembly might make proper contact after cycling the mechanism. This is unlikely to work if a spring meant to ensure the contacts touch as intended no longer functions:)
Cheers Big Clive,
Wait; I was waiting for you to put the bits back together.
Maybe next week?
Cheers,
I wish consumer light switches were available with that kind of umpf. I prefer this kind of tactile feedback to e.g. touch switches.
I agree. The ball and socket went hiZ and the spring became the path of least resistance. They should have insulated the spring in a plastic sheath to preclude this failure mode. 3cent solution, and would have made it last forever. What you did is called a DPA Destructive Physical Analysis in my old field of business.
Fusible springs are new to me...
Just like watching cars race at the track, there's no skipping ahead or pausing the video if there's a chance of blood, injury or death that we might miss out on. A simple guiding principle for TH-cam video production.
Clive is usually nice enough to inform us of any blood with a parentheses in the title.
I supose one option for those that prefer the pauses is to include time codes in the video description (and if you put a time code for each part of the video, including one for 0:00, then the time codes will turn into video chapters, assuming the feature works as it is supposed to)
Well I was going to say I had a brief opportunity to try this, and i get to the end of what you were saying and I was like it actually works amazingly well.
Literally all you have to do is put text with a number and it creates a chapter as in : "0:00 the beginning of life the universe....." Just recently did a video and I was so expecting to have to look it up, I edited the description and boom.
Excellent autopsy! Thanks Clive and Richard.
Electrician in the Navy. We were taught that the first blown fuse was a gimme. You could replace a blown fuse once without a lot of troubleshooting. If that second one blew, you had to tag it out and troubleshoot, figure out why. Same sort of 'tired fuse' idea, sometimes they just blow for no real reason.
"Detective Clive at your service. Ralfy, we have a new case to solve..."
I have an older lift disconnect, made around 1938 (installed 1939, according to the register in the motor room in the commissioning phase) which has no fuses, but instead has oil filled dashpots in an oil bath, with a current coil per phase to provide the force. Then also has an ammeter integrated in the top cover for showing power draw, only though on the one phase. All cast iron and brass construction.
Was replaced during a modernisation, as the dashpot oil bowl was broken long before, and thus trip current was no longer adjustable for delay on starting surge. New replacement was a 3 phase circuit breaker, 30A, with the cable breaker in the supply from the ground being a 40A unit. Also made a LED power indicator, which was integrated into a full size breaker blank and potted in epoxy. Used a red 5mm superbright LED, a bridge rectifier and lots of series resistors for power and voltage handling. 39k 0.5W carbon composition resistors, 3 in series, so LED current was around 3mA, which was bright enough to have a red spot on the far wall. Lift draws around 20A peak on start, and runs around 15A when steady, so no issues with that supply now.
It's it the type with the big button on the top?
@@bigclivedotcom Yes, plus has the optional meter.
Your videos are excellent, enjoy watching them so much. Also always listening out for 'one moment please' :D
I now unconsciously say the exact same thing when dealing with a problem requiring a few more moments thought. Wills never get the BC Accent though!
I've just purchased a pair (2 sets) of Sennheiser HD202's in quite good, but used nic. Got the pair (2 sets) for $40 USD. This video sounds particularly good when enjoyed through these headphones as does my new E-drum set. The bass in your voice is very full, warm and properly bossy.
I once was (at first) blamed for what turned out to be a "tired" fuse when one blew in the disconnect feeding my portable distros and dimmer rack during a load-in.
It somehow instantly took out the entire building as well, which wasn't good in a hockey arena during -30F weather. It got cold inside, but not too cold to ruin anything before it was all back up.
Cold seems like a good thing in a hockey arena in my mind 😉
@@oliverer3 thank you that's what I was going to comment. Yeah I always suspected of house electrics. It's the number one thing I can't test enough.
They have big switches like this on large commercial air-conditioning and refrigeration units and such as well. Provides both fuse protection against overloads etc and a way to be absolutely sure the device is off when working on it (without needing to go downstairs and turn off/on the main breakers for the unit all the time)
Another source for contamination are metal parts that has been stone tumbled to take the biting edges of stamped parts, the stones would of course wear to sand in time. The small parts manufacturer are sometimes sloppy in the clean up and the assembly people just didn't notice. The sand would have dried/caked in crevices, and then loosen with the rattle of the spring loaded mechanism.
There was a MEM brand switch in my old workshop that had three fuses like those but they rode in and out on a carrier with two prongs top and bottom for the switching action, made a very loud noise when the lever which was on the side and had to be pulled out was thrown over either way but switching on was slightly softer than off. Very simple and robust,as long as it was greased every so often nothing to go wrong.
The small springs that put pressure on the contacts likely overheated from poor electrical continuity between the main arm and contacts letting excess current go through the spring. I've replaced micro-switches that failed in a similar manner - poor contact between the common post and the switch arm causing current to go through the snap-action spring, causing the spring to overheat and lose its springiness. The loss of contact during mechanical movement does not need to last long for enough inrush current to overheat springs.
Thanks for reiterating exactly what Clive said.
@@xenonram Wrote that before reaching the end of the video. Ideally, that thing should have had braided copper crimped or welded between moving pieces to guarantee a good chunk of the maximum allowed fuse rating and prevent arcing/pitting/welding between moving parts.
We called them CFS Units [Combination Fused Switch]
This type are a simple side way slide mechanism, using heavy over balance mechanism enclosed.
The type I first starting with had a carriage that was also spring loaded to thrust in or out. The carriage could be totally removed for service or absolute isolation of the fed circuit.
They are designed to break 'on line' loads.
The last heavy units I worked with [manufacture of power station switchboard] was 3 phase rated at 660V A.C. @ 2,500A. We used them for a 220V D.C. application by double switching the positive buss feed. Likewise, using 3ph 2,500A A.C. programmable Circuit Breakers in a D.C. distribution board. Heavy 2 x 125mm x 10mm Cu. per phase or pole busbars in these, requiring precision bending to maintain consistent bar gap and very fine tolerance at every lap joint, be that between shipping sections, buss ties or CFS and CB equipment.
This 660V 63A 3ph POS... Can't say I like the design of those spring loaded floating contacts. WFT... not even a heavy welded braid connecting to the fuse mount lug! Like, might be a cute little baby size FS, used as a local isolator... or maybe in a dis. board? I've seen 'em used with solid copper bars instead of fuses as a cheap means of 'on load break' local isolation switches.
No matter how good the 'rocking' contact connection is, the spring will take some small current. All of the springs I could see in the video looked a bit corroded. So if they're the wrong type of metal, as I suspect, the springs would be subject to electrolytic corrosion. Any heat from the high current would just make it corrode faster.
Thank God almighty Clive! At last something nice that is not a cheap led chinese led lamp teardown... Go on, don't waste your talent 👌
Knowing when not to go bareback. Priceless.
I watch some hvac channels and sand in disconnects, contactors and time clocks is a killer. It takes just one grain in right place.
Yeah, it jams gears solid.
Sand in contacts, or dead (dry) insects can and does cause faults. Sand in mechanical components is even worse, especially if it contaminates the grease or oil that is supposed to lubricate moving parts like gears or bearings...
@@Mark1024MAK The dead insect in a relay contact was supposed to be the origin of 'bugs' in computer code. The original 'bug' was supposed to be a dead insect that stopped one of the electromechanical code breakers working at Bletchley Park in WW2. Someone found it and held it up with a pair of tweezers and announced the problem is a bug.
@@johnmurrell3175 - yeah, absolutely. I’ve also had it myself with electro-mechanical equipment that uses electrical contacts. It doesn’t happen very often. But occasionally an insect or similar will get inside the equipment casing and then at some stage the contacts will close. If it’s in the way, it will be trapped, and the contacts may not make properly, hence causing a fault.
And electronic solid state systems are not immune to the problems of nature causing havoc. One failure of a system was due to a slug moving across some 240V PCB tracks, then dying. Then the gunk corroded the PCB tracks which caused a failure...
@@johnmurrell3175 That folk etymology is not correct. Bug was used as slang for a problem in engineering since the 19th century.
We call them CFS units here in Straya.
Combination fuse switch.
Best to pull them apart when they are closed, the springs less “hurty”.
I always find it funny how they sell phases in lots of three, and fusses in packs of ten.
First thing I said when I had the factory tour at my current job was have you exercised you're breakers on the subs. Seen too many factories where it's never done and when needed the pneumatic breakers don't work after many years of sitting idle...when they had it tested it had indeed failed... luckily they had the sense to get the dno on site ready in case of a problem.
Clive: Puts unit back together. Builds a small lawn mower with the bits left over.
_"...slight risk of impalement."_ is not a phrase one hears every day, unless one is employed at an archery range. It's giving me the same uneasy feeling as when one of my favorite firearms-related channels happens to point their camera down the occasional gun barrel.
Fault investigation is always fun. The last case I came across was a tripped breaker from a short circuit. I determined the root cause to be a stray metal object bridging the exposed live and ground on a regular American 15A power plug. Our plugs really are the worst, almost every other country's plugs are made so you can't contact live pins.
In the old days, at least in the USA there was a different philosophy, the equipment was designed to take a full fault and remain in service with just a fuse change.. and the fuses are all rated at 200KAIC. When I first encountered ICE components I was shocked that the design philosophy was that it did contain the fault but at the expense of itself and half the the equipment it located in.. We had and still have plenty of crappy designs but Fused Disconnects are particularly hardy.
NEMA OVER IEC all the way! Give me Any Square D or Allan Bradley NEMA rated motor starter or contactor any day! IEC Inferior European Crap! I deal with that stuff every day modifying so they meet CSA and Ontario ESA standards. From fuse holders to contactors and many cases design issues from grounding and bonding to the misuse of auto transformers instead of step down transformers, just simple build quality when it comes to electrical
@@carlubambi5541 Agreed on the NEMA and UL standards but take it from me (someone who has sold over 200 million in electrical equipment over the last 40 years) SqD and the other US manufacturers are a ghost of their former self.. Most are to owned by US companies and are not taken seriously by their parent companies.
Allen Bradley (now owned by Honeywell) is still a quality oriented company..
The new moto for these formerly great companies. NOT ENOUGH MONEY TO DO IT RIGHT, PLENTY OF MONEY TO DO IT TWICE!!
Interesting! I've never seen such a combination in the Netherlands before. I can only relate to fuse-disconnects that have the fuses (we call them knife-fuses) clamped into a cover that one pulls open to break the circuit if needed (and of course pushes shut again when power needs to be restored)
Switches are always single parts added when breaking the circuit by actually removing the fuses isn't such a good idea anymore (I think above 63 Amps) or (probably) when the fault-current exceeds a certain value (when the switch-cabinet is located close to the transformer and the circuit before thus has a very low impedance)
At first I thought you said to "bear with me as I "fiddle about" and I immediately had a vision of Kieth Moon as Wicked uncle Ernie. Now I feel like getting electroshock therapy to hopefully remove that vision...
Don't you mean 'Cousin Kevin'?
When in doubt, put on gloves and remove all the screws.
I find myself looking for the Explosion Containment Pie Dish, even if nothing will explode, it would also be handy to capture liquids.
Ok, that's really cool. The huge spring in the actuator makes sure the contacts close really FAST, but the little spring makes sure they don't close HARD. Do you thing it was running hot enough to distort the spring without messing up the adjacent metal?
It looks as though the spring took the full load. The adjacent metal wasn't obviously overheated.
@@bigclivedotcom Yeah, I posted my comment before you discovered the sand. I should wait till the end of the video before commenting... Astonishing how just a tiny bit of debris knocked out the whole thing.
I don't think they care about contacting hard, The small spring would just allow tolerance in the range of motion of the device (pin arm push assemblies like that are terrible for maintaining tight tolerances in the final position of the end of the contact), so they can have error/wear in the assembly but still make proper contact/disconnection. But you are right about the spring cartridge in the back causing a hard fast snap to bring ALL contacts together with as little as possible time to arc and timing variance between making connection between the legs. Maybe also causes the contacts to separate in a speedy manner as well to limit arcing.
@@Tom89194 I figure that repeated hard contacts might flatten or damage them, although that might be a good thing, if it had closed hard, the sand might not have affected it.
I thought that was a zoomed in shot until your hand came into frame. That breaker is massive.
It's a tiny little baby 660V 63A 3phase Fuse Switch. Seriously... it's very small.
Thank you Clive!
Cheers Clive! I can't believe that's all it was. You could be right about the sand, as another engineer did replace a fuse after the lift developed a fault a year or 2 ago.
Where is the lift located - in what kind of building? How old is it?
@@milcotto4153 It's in a 2 storey office building in the UK and is around 30 years old.
forensic clive finds springy fuse! Thanks it was interesting.
As a Sparky from Australia I would describe that as a CFS unit. With CFS standing for combined fuse switch.
Think I need to add some new pieces into the BigClive Cludo set ... it was the silica sand, in the fuse box worth the high current!
Good investigation ... not sure we have enough to convict... think you need to sample the sand, ponder a bit, and then explain which beach it comes from, hence the production line and ultimately lead us to the discontented employee with a grudge against lifts. 👍
Here in the US we just call them 'fusible disconnects'.
You bloody well would?😂
Should you order "chips" or "fries"? Rent a "truck" or a "lorry"? Stand in "line" or "queue"?
Anything can be fusable with enough power...
@@groovejet33 if you get lonely you can dress up your carriages in boots and bonnets and take them out for a jaunt
Everyone's a bloody comedian 😂😂😂🤣🤣🤣
@@groovejet33 See we 'Mericans are simple folk. We don't call our chips crisps, nor our fries chips. The only queues we have are sweet and we don't name out trucks Larry. Honestly, what's with you British folk calling every truck Larry? He a local legend or somethin'?
It would be interesting to cut / break one of the fuses open to see if the sand in the fuses is similar. The 'snap' action is required to minimise the contact arcing as they are opened or closed..
As an aside Lifts are quite interesting as electrical loads as they regenerate when the control system controls the lift speed when it is imbalanced. We had a couple of lifts that caused problems due to this - one the electricity meter (rotating disc type) went backwards when the lift regenerated and it got very confused about the power consumption. In another case there is a station that has 4 AC lifts on a feeder from the street supply. When the lifts got into phase so most of them regenerated at the same time the voltage to the local shops went above the normal supply limits ! In normal buildings you do not see this as the lift power is only a small fraction of the building consumption. However in the two cases above a new feeder was put in just to supply the lifts the other supplies for the station being derived from other sources.
Loosing a neutral is always fun when it turns into a star point!
I must admit I am quite fascinated by really high current gear. We are having a new machine line installed at work and they have just had about 20 people in to pull through a great big fcuk off SWA cable the size of my thigh from the substation along the cable trays suspended from the roof! You should have seen the size of the drum it came on! Was talking to one of the guys who looks after our substation and he was saying when they liven up really big stuff they don a flash suit that wouldn't look out of place on an episode of Captain Scarlet, stand off to one side and then twat the breaker with a long big of wood! When you are playing with power levels above a certain level it's not the electricity that gets you, it's the flash and the bang!
I mean the electrical load just for the *lighting* in one of the machine halls is probably about 40kw... God knows how much the total load for the whole site with all the machinery is!
Having installed similar cables I don't recommend it for fun.
Not in the industrial application, but I remember bits of card with different fuse wires wrapped them, for the home. Then if the fuse blew, you simply picked out the right wire (well hopefully right wire) wrapped it on the post and off you went again.
Yeah, as I kid in the UK I remember that as well. And I was always putting plugs on appliances. They cam without back then.
Featured in an older video on this channel.
You can still buy fuse wire cards:-
cpc.farnell.com/pro-elec/fusewire/fusewire-5a-15a-30a/dp/PL09979?st=fuse%20wire%20card
switching on a 2000 amp 3 phase disconnect is fun, the handle has a long pipe like rod that come out of it and you need a exert pipe over it to leaver it on
Fantastic analysis. That was fun.
I first heard the expression "old and tired fuse" in my teens, after a "mystery student" caused a high-rated DNO phase fuse to expire without disturbing the sleep of lesser-rated fuses downstream.
The high current was caused by inserting two keys (hanging on the same metal ring) into the L & N of a socket outlet, and turning on the switch. The keys made it across the room before the lights dimmed and then went out. It was an incredibly stupid thing to do, perpetrated by one of the smartest students in the school. I merely watched and encouraged him, feeling simultaneously fascinated by his idea and in dread of the possible outcome.
It took hours for the school to diagnose the problem and then for the DNO to attend and replace the fuse. In hindsight, they might have had to do more work than just insert a fuse - if the carrier[s] was[/were] ancient and made of hewn slate then I can see them wanting to do an upgrade on the spot.
I'm sure the incident is long enough ago that nobody in authority at the school will get to read this or take retrospective action but, just in case I'm wrong, my name is Boris Johnson.
I was always taught that a switch-fuse is a combined isolating switch with a fuse affter it, the fuse being permanently connected to the output
A fused-switch is like the MEM (the ones you can remove the carriers) switches where the fuse carrier moves and makes contact both ends, so when it's turned off, the fuses are disconnected totally
Not sure how that one would be specified, but closer to fused switch
.........and on the fuse replacement subject; you absolutely must, in every circumstance with three phase loads, replace all three fuses as a set!
Length is good for you and choice is good for us.
hahahahaha i was nervous about the spring the entire time, even with the glove on.
Fill them with water and freeze them before taking apart.
Paraffin sounds like a better idea.
Why does europe use currents like 63 amps for this specific instance and 32 for a ring main in the house. Why not use round numbers like 30 and 60 or 65 like you'd see commonly in the US
I think the currents were based on standard cable sizes.
Round numbers are hard to mount, the slightest tilt and they roll of into the most difficult places, so when youu need 60 they include an extra 3. "/
@@snakezdewiggle6084 Smarta**
It's clearly a calculated size.
One answer is that you should not be able to run a fused network on the edge by using 2x32amp fuses on a 63(64) amp fused main. So you can add only use a 16 amp fuse and or 6/10 ones and still have a security margin to not overload the wires and contacts. That's why there are odd numbers. A security precaution.
"you hit the nail on the head" with the failure diagnosis, which probably stemmed from a phase loss and slow cooking fuses in the past. when slow cooked they tend to be real brittle and will shatter when replacing, dumping their shmoo everywhere. lol
That reminds me of a similar case in a very different appliance. I replaced a blown 3 A fuse inside a 12 V cigar lighter plug by a 12 A one because I did not have any other of this size. It was only for a short test with short periods of maybe 6 amps. Suddenly the current was broken and I wondered why the 12 A fuse should have blown. Further investigation showed that the spring holding the fuse in place did not like those amounts of current and got so hot that it melted the plastic nearby. This resulted in the relaxation of the spring thus loss of contact pressure pretending a blown fuse.
Oh that is wonderful!
As someone who's done electrical work for a place that effectively lives in a constant sandstorm of extremely fine-grade sand, I can say sand kills literally everything. We've had Class1Div1 equipment come back nonfunctional because the sand got inside. It's insane. Sand gets literally everywhere. You could have a sealed bottle of gatoraide and at the end of the day it'd have sand inside it despite not leaking a single drop of liquid out of it.
And I still don't understand why people want to go to the beach for many reasons. Number one on my list Sand. They always come back and complain about it but I'm like you went to the beach!
This is apparently is one of the trickiest parts of designing a base on the moon. Lunar dust is very fine, which renders it difficult to filter, but highly abrasive, which means it will destroy mechanical systems over time.
@@allenlutins It was a sandblasting company. Equipment rated for fine dust with 10 year warranties was garbage in 3 months. Insane.
Big switches like that used to have spot welded braid wire to the moving contact. This switch is missing the current carrying braid, so the current can travel the piviot and spring, resulting in heating of the support components. If the spring was on an insulator to prevent it's heating from current conduction, the other higher resistance points would have heated instead. The spring failed and the contact opened. The spring should not be a current carrying component in the switch. A low resistance path around the spring is lacking.
Again an interesting video :-)
Could they have installed the whole thing horizontally? That way the fuse silicon falls into the mechanism.
Greetings from Nederland.
If you could get your hands on an elevator relay assembly that would be cool. I built a small scale version once. Works great but I would still say slightly dangerous.
I didn't think you would struggle with those gloves for long. I wonder if the manufacturer would be interested to see that video if it is still a current model.
My dad is a PSE with the city and had one of these fail when he was changing some 600V meters one morning. One of the disconnect modules failed to disconnect and when he inserted a new meter it arc flashed in his face. He wasn't wearing a shield, but luckily he had his safety glasses on as well as a flame retardant jacket to save most of his vital bits from being flashed. It's pretty scary when electricity discharges uncontrollably.
Something similar happened to me in the '80's. Overhead Crane Hoist contactor in a steel mill shorted out. Woke up in the ER as a Doctor was picking beads of copper out of my face. Safety glasses were so well copper plated you could see yourself in them. Pretty singed, but mostly recovered in a couple of weeks.
Forensic excellence! 👍😁
63A? Is that a typical fuse size over there? How interesting. Any large new construction project with fuses (not that often in the last decade) I specify a fuse cabinet in each large electric room with at lease one full set of each of the larger size used, and a few sets of the smaller ones (20A, 30A).
No sliding contacts. That's the weaker construction, also when used in corrosive environments like paper mills.
The ones we sell have knife contacts sliding between a springed fork. Wipes clean at every action. Will not try to disengage on short circuit, cannot bounce. 100kA @690V rated.