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.
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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:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
These vids are like ASMR to me… the voice, the little noises, the clicking and clunking the pauses for thought…. Ahhhhh lovely!
In my world, industrial automation, these are referred to as "fused disconnects".
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)
This is gold
i was kinda thinkin the same thing, along the lines of fixability, when u were takin that screw out of the side of it, i was surprised it was a screw n not a rivet
Don't like that fuse style, knife edge fuses seem safer and more reliable to me, no nut or stud to strip ;p
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)
"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
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.
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.
Quite different to North American NEMA rated gear. IEC stuff is much less robust, and way more complicated. NEMA stuff uses sliding contacts. Usually, they are a single contact per pole, so the fuse is still connected to the load when the switch is open. This could not have happened here. Once the switch is made, it is made, and it won't fail open. In theory, a FDS can be opened under load, in practice, don't do it! Out of curiosity, how can auxiliary switches be added to that device, if you wanted interlocks or indication of the switch position? As for the neutral: I worked mostly with 3 phase, 3 wire, 600 V, 60 Hz, usually with a high-impedance ground. Some installations were completely ungrounded, but that was real old-school, not much of that left. Makes for very high reliability, as one phase can go to ground and not shut down the plant or even blow a fuse.
I think maybe the violence of the snap action mechanism had sprung that spring loose from the nubs holding it in place, and it had fallen onto the contacts.
👍.
Always called them fuse blocks.
Vote for no pause. If you pause inevitably we all miss the exciting moment when the thing explodes and vaporises a digit or two 😀
As viewers we can skip or playback at x2 at our reclined leisure.