Blowing a high voltage fuse

I found this high voltage fuse on the transformer in a microwave. It seemed a good idea to blow it for educational reasons.

Note that most modern home-microwave magnetrons do not use beryllium oxide insulators, despite the negatarian folklore. But always play safe and assume the worst.

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#ElectronicsCreators

[jasonkuehl]

I'm not sure exactly what I expected from that fuse, but was still surprised by the amount of motion. Simple and effective, the way things should be! 🙂

[robertleifeld]

Oh MY... Shades of PHOTOINDUCTION !!! The channel was live about 10 months ago and lasted for 2 months with a promise of returning. Lets all hope that he returns soon as it certainly lightened my day -- literally with flames, motors running at 100X (or more) rpm until all their parts fly out and it grinds to a halt making a wonderful screeching noise. A seriously great channel to watch while we wait for the next Big Clive.

[Sylvan_dB]

Very nice! Even at 1/10 speed there is a brief glow and then when it blows the retraction is instantaneous. It'd be wonderful to see this with a high speed camera.

[SeanBZA]

Beryllium oxide is actually very white, no colour at all, mainly because the intended use is for high voltage and really good heat transfer, so it is very dense, and normally quite thick. I have some, and the only way to actually tell is with a X ray diffraction, to tell apart from aluminia. Only warnings about them were in the service manuals, telling to handle with care as they contained beryllia. Incidentally a lot of spacecraft alloys, and all high pressure gauges, contain beryllium copper in them, used in spacecraft to make thin high strength parts, and in gauges for the actual Bourden tube used to sense the pressure.

[lildvsvevo]

Clive: “you shouldn’t really play around with these”

Also Clive: “hehe fuse go pop”

*This is such a mood*

[ParedCheese]

Cool! 👍
Would have been interesting to see how big the arc would have been with a HV source. 🤔

[JayJamsSpams]

Some types of fuses in medium voltage substations fire a spike out of the end cap when the fuse blows. The spike pushes a lever which shuts off all 3 phases. Would be good to see Clive play with one of these!

[WineScrounger]

The alumina/chromium oxide insulator is exactly the same colour as the refractory gas shrouds used in TIG welding gear. I’d bet they’re very similar in composition.

[jonpattison]

High voltage fuses can be quite interesting. In the early eighties I worked on a piece of equipment that provided directional info for military pilots. The final amplifier used 3000 volts and was contained in a drawer of the cabinet. If you tried to open the drawer with the high voltage enabled, it shorted the supply with a ceramic resistor about the size of a paper towel core. The resistor didn't would experience "very audible instantaneous disassembly". So after everyone within 100 yards stopped laughing and you changed your underwear, you had a lot of ceramic dust to clean out of the equipment.

[cwcordes]

This spring loaded fuse reminds me of a previous life. About 50 years ago in high school in electronic shop class we were trying to make a video switch for our fledgling video lab . The single pole switch did not work. The video would just leak across the switch gap. We had to reduce the capacitive coupling. Someone came up with the idea of using an eight pole switch and connect all the contacts in series thereby cutting the signal 4 times increasing the gap and reducing the capacitance .. It was a splendid success.

[gusmartin]

I love that Clive always gives sensible advice. Not being over cautious or wireless, just making people aware of the nasty bits, and leaving it up to them to do what they will with the advice.

[jordsoo]

I love your videos Clive, I had a bit of a worry recently as I had been pulling apart microwaves just to scrap their parts. The first one I did I took apart quite a few things, even components without 100% realising. You touched on the thing I was concerned about in retrospect after I had watched a video from someone warning about Berillium oxide. I now know that it can be aluminium oxide with a bit of chromium oxide. I just wanted to take the time to say I've always found your videos highly informative and thank you :)

[lifeoftekki]

Well since Mr. Photon seems to be lost again, thanks for popping things.

[CRWhiteside]

Big Clive channelling photonicinduction with this!

[boahneelassmal]

any video that begins with the words "while dismantling" you know it's gonna be good

[MisterTalkingMachine]

I have opened many microwaves over the years and I have never seen a fuse like this built into a plastic housing, They are usually glass bodied fuses, same structure, inside a protective plastic shell

[BeanyFTW]

That is, from a relative layman's perspective, quite neat - the risk of high voltage over normal voltages is arcing, so make a fuse that can't arc.

Nicely designed.

[walula]

This was much more than just blowing a fuse, thanks for clarifying the beryllium misconception.

[TomsBackyardWorkshop]

I've found blown high voltage fuses at work that have exploded. The equipment I work on is extremely high voltage and when a fuse blows it creates an arc. The spring is there to pull the conductors apart and extinguish the arc. If it doesn't work the arc grows until it explodes. The explosion is relatively small but still quite dangerous.

[billsmith]

In the old electro-mechanical telephone exchanges and associated equipment a spring loaded fuse often referred to as grasshopper or hopper fuses were commonly used. This would be a insulated material like bakelite with two spade terminals each connected to a piece of flat spring metal each with a hole in it where the fuse wire would be threaded through and soldered. When reaching melting point the fuse wire would melt causing the two spring to jump apart. The bottom spring would be on the supply side and on springing apart would make contact with the fuse alarm busbar. This would bring up an alarm and indication of the locality of the blown fuse. These fuses had different colors to indicate the amperage. On some radio equipment we had fuses similar to the one you demonstrated except they were glass tube encased with the coil spring. Often referred to as high speed fused. Then we also had glas tube slow-blow fuses. Similar glass fuse with some granular substance inside and I forget right now what the granules were.