I like how that waterproof package is basically exactly the same concept and construction as glass envelopes for light bulbs and vacuum tubes, just done with plastics instead of metal and glass.
@@Z-Ack very cool stuff. It's funny how when he started thinking about how the wires are crimped together I was like" this is so interesting!" Probably to only like 5 people! But turns out it's a bit more than 5 :)
Well, that thermal fuse design explains why i keep seeing these getting intermittent! At work we use them in gas reactor tubes that abate gases coming from semiconductor production tools. 184°C fuses. A column that has shut down will often be resetable once it has cooled down, but will turn off after half an hour, and the fuse would still read continuity when you arrive there. That's one of the many traps for young players. Change that fuse based on its paint burned up, not from what the meter tells you :p
Clive, thanks for the video. That is a super low cost defrost bi-metal switch. Definitely not hermetic, as moisture can migrate through that plastic. This design is a step backward, the previous versions clip onto a pipe on the evaporator to sense temperature so, this design will have thermal lag. The "N12-5" number lists the cut-out and cut-in temperature, although with that number, there should be either a F or C suffix which denotes Fahrenheit or Celsius. In the number, the 12 is the cut-out (or open) temperature, most likely in Celsius. The -5 indicates the switch will close 5 degrees below the cut-out temperature. So, the switch will open at +12C and close at +7C degrees as marked. Originally, with "frost free" refrigerators, the defrost cycle was controlled by a motorized timer switch. Since the 1990's, the defrost is controlled by an electronic circuit that makes the decision to defrost based upon the amount of time the compressor runs and the number of door openings. When defrost is activated, it turns on a (typically) 600 watt heating element that is connected to the bottom of the evaporator coil, which runs for 10 - 20 minutes. After the defrost cycle ends, the refrigeration has to remove all of that heat. The defrost algorithm doesn't take into account relative humidity in the room or makes no determination if the ice is actually melted on the evaporator so, in addition to using electric resistance heat (versus heat pump mode), it wastes a lot of power.
Nice vid Clive. I often encapsulate small modules in clear, glue lined heat shrink, I crimp the ends whilst it's still hot, then pump in hot glue in the wire end, re-heat and it's almost potted. Have loads of IoT modules around the house done like this.
In a world where everything seems to have been simplified down to just be some chip or discrete sensor, it's always funny to me to see things like that thermal fuse that are sorta like some medieval contraption but with electricity
Safety devices should be as simple and reliable as possible. Springs opening contacts, energy loss shutting down devices, gas pilot lights with automatic shutoffs, etc.
The design of the thermal fuse is really quite surprising. I also did an autopsy a fuse like this from a broken iron and I wasn't smart about it, so thank you for the helpful information.
Speaking of irons and thermal fuses. This I think was an older model but don't know for sure. I was scrapping an iron for a few things and also use the base/ soul of the iron as a weighted base for something else for a tool Mount I think it was it may have been I was using it to make a soldering iron holder for someone! But the thermal fuse in that iron was something well rather intriguing. It was not standard little cervical thermal fuse like the one in this video was. It was essentially to contacts brass or copper alloy or other that that a bit of a spring to it. There were two circular portions of the contacts that were essentially soldered with a low melting point alloy. And that was the thermal fuse itself! Also I was working on an old movie projector which I wound up salvaging in the end once it died! The Intriguing thing is the internal Motors were actually 240 since this was originally built in Europe. However the power transformer was designed for use with world voltages. So this Transformer also acted not only as the lamp Transformer and a step-down Transformer but also a Step up Transformer! And when I was in there trying to check some voltages I got a nasty surprise happened to bump the terminal on the Transformer they're like whoa that's more in line voltage turns out I I had received a 500 volt shock! So I put it like that that's designed for multiple countries and is produced in Europe be careful that's not something I expected in the least and because it was so dark inside of it it was difficult to see and almost no terminals were labeled besides the input selection terminals for line voltage selection. No mention of very high voltage or whatever inside you think there would be some sort of warning when that voltage is present! And yes it was being powered from 120 volts here in the US! The other interesting thing is instead of a fuse or even a thermal fuse this may have been used for both simultaneously possibly. It had what I would describe as an open link fuse with a spring hooked on one end of the s-shaped hooks of the fuse element. Essentially a low melting point elderly attaching to pieces of either copper or other metal alloy. Essentially two pieces of metal and solder was the actual fuse! And fairly strong extension spring! Not sure if this was intended to be blown by current or heat or both but I suspect both. Also I'd seen something similar to that iron thermal fuse but on a smaller scale inside of some old hair dryers every once awhile but not very often mostly very early ones probably wasn't the best idea to take those apart since their mind have been asbestos! But those hair dryers continued to dry hair! This is long before modern hair dryers but still looked like someone the modern ones back when they were just the two prong cord and no fancy gfrc and ionic whatever where all you had was on off cold high low medium that's about it. Later on they would add a diode to do away with one of the heating elements essentially feed half-wave rectified to the heating element to reduce element power output. Much like the old Radio Shack dual heat soldering irons more old school hi low dimmer switches. I'm wondering if there's anyone that makes a night light fixture that has a diode in series with the socket to increase lamp life and dim it quite a bit as well of course incandescent and this needs to be for 120 volts ac for United States as well! I know when option would be a nightlight size and wattage bulb that would be something like a 220 volt indicator in place of the steering night light bulb but that's harder to find but they do exist probably costly to get potentially as well
I've seen hundreds or these fuses and never knew how they worked-thank you. THIS EXPLAINS WHY I KEEP GETTING CALLS FOR THESE FUSES BLOWING IN WALLOVEN. for some reason they have put these behind the controls of whirlpool wall ovens and if a customer leaves the oven door open too long it blows 👍🤙
@@gags730 that's the plan. Planned obsolescence and intentional murder of the repair market. It's sabotage. It's "products as a service". It's "sustainable income". It's a weapon to kill human prosperity and replace it with turning humans into bags of meat - tax cattle. Unfortunately, trying to explain to a meatbag that they're a meatbag doesn't work. Oh well, not a loss, they ARE meatbags.
Low temp alloys would not have the mechanical properties to be draw into wire. It is usually a button or a plug. Honestly the best you could hope for is a tensile of 5k psi with an sn/bi eutectic. The rest are drastically less.
These things often have to conduct the whole current in series with a line voltage (120/230/240V) heater element or heat pump compressor, so you can't really make the wire that fine.
I'm working on a device that needs wires to exit a sealed pouch so I'm interested to see a commercial application. Air does indeed leak down multicore wire, and I guess moisture could also wick the same way, so I'd hope the heat-sealing overcomes that. In my case, I've used enamelled wire rather than stranded to avoid the problem.
I have done something similar in the past with success. I use solid core wire and strip the insulation off the wire, then heat seal. Same premise as what’s shown in the video, but with solid core wire and no insulation at the point of the heat seal. Obviously it’s important to stop adjacent conductors from touching while heat sealing, but it hasn’t been an issue for me yet.
Yes, things can wick down a stranded wire. I have had batteries leak and found the corrosion wick like 6 inches down the wire finding green corrosion the other end.
I've worked with a sensor that had to be waterproof, but had a connector at the end of 20cm of stranded wire. We used "sealed" wire, which had small blobs of silicone sealant added to the strands every two cm or so. That makes the wire more expensive, of course, but it did a good job of preventing moisture from moving down the strands.
Had to have a look and found there are 3 main types of thermal fuse. the sliding contact like the one you had and two with a form of low melting point wire and resin. then the wire melts it forms two balls on end of the broken wire. the resin helps with the balls forming due to surface tension on the molten wire and also to form a insulation gap between them. Used them a lot but never thought about how they worked, just about what temperature they will trip at. Used to solder a few but used pliers as heatsinks to stop them tripping from the soldering. Always a nice little addition to the side of a mains transformer. Or if you want to keep the repair bills up a bit inside the transformer. 🙂
I like when you don't pause and show us the whole process! Few people show what it takes to open or even repair something that seems trivial such as opening that sealed sensor. I find the entire process from beginning to end interesting, it's like a "mental rep" of me following along with my eyes as if I was doing so myself. Love this videos keep it up!
Hey Clive! You did, in fact, already open one of those thermal fuses. It was in one of the older heater videos (Like the pink one, the blue E27-type one and the Clothesdryer one)
I had to do a post mortem on equipment that had a thermal runaway. The factory it was located at suffered a power surge due to a lighting strike and as a result the solid state relay controlling the heater shorted out causing an over heat condition. A thermal fuse would have been the last defense against runaway but the surge cause the thermal fuse to explode and the center pin became welded to the case. Eventually the equipment got so hot that the wire nuts in the solenoid valves, located in the insulation space, started melting and exposed the metal inside which came in contact with the case of the solenoid junction box causing the control circuit fuse to blow which opened the heater contactor.
That's interesting, but brings back bad memories. My fridge was having some issues recently and while trying to fix it I stupidly touched the defroster element while it was running to see if it was working. For some reason I thought: it just needs to melt ice, it can't get that hot. Well I got incredibly painful second degree burns on three fingertips in about half a second. Protip: Don't touch the defroster. That fridge is now in the junkyard.
Fantastic video. As a former home appliance tech, i have replaced that type of defrost stat more times than i can remember. Lots of fun to -see- the insides, not just know how it works. You nailed the explanation of how the timer works as well. A treat too, to learn and see more about the fuse pal, always a pleasure. Thank you kindly!
Good info, I assume that what might appear to be a minor dent on one of those thermal fuses could in fact completely DISABLE/JAM the internal sliding contact break operation! Struth, who would have expected that minor thermal fuse case damage is potentially dangerous? Maybe this vulnerability needs a bit of research & publicity to avoid electrical fires? Thoughtful Moment .... I nearly had a serious house fire a few years ago when a (new but mostly plastic) fan heater was found to be burning furiously in a briefly vacated room. (luckily smoke alarm went off). I couldn't work out why the thermal fuse must have not tripped until after the heater was well alight. I didn't look for dents in the fuse's case.
yes the thermal fuse is working like that, this "compound" or wax stuff or whatever it may be made of has a certain melting point which is melting letting the contacts slide away from each other. it is actually pretty common fuses like this goes open over time even if they don´t pop. soldering them can be a hassle but it is possible even with the 70 degree ones. when I do solder i use freeze spray to frost the fuse body and use a very high temperature on the iron to as quick as possible solder the ends of the leads to the device, wires or PCB and then cool down the legs with the spray before the heat goes into the fuse. it may also work to hold the lead tightly with a thick plier while you do, it depends on the rated temperature of the fuse
I absolutely love that packaging! Now I'm gonna have to figure out how to do that. Hmmm.... If the plastic cover is the same material as the wire insulation it should not be that hard...no reason it would hurt the wires, it could expose copper, but then it would still be covered in melted plastic. I wonder if I could use a modified impulse sealer with some notches for wires. Oooo....then you could inject the entire thing with hot glue or silicone.
thank you for the diagram of the thermal fuse, i've broken plenty of these but i've never investigated further than a tertiary glance at these and never had enough inclination to pull up a patent or anything
These exist for one reason because the thermal barrier to the thermal fuse and when you get massive condensation in a humid environment. The original designs only had one sensor in the fridge or evaporator so there was no software fix to stop it blowing the fuse, the thermal switch allows it to cycle the defrost system and hopefully get it all done before the end of timer. What might be interesting to explore is just how good an insulator ice can be in these situations where you have a defrost system running and parts of the system cooking and the the ice can shield parts of the controller system, its a minefield.
For that fuze - now that you know what the guts of it looks like, get another one and deliberately blow it, then cut it open to see what happened. The functionality will become apparent. I've been in high tech for 32 years now and am rediscovering the tiny component stuff thru you - it's refreshing and tremendous fun. :-)
Speaking of passing air through wires, at work we have pressurised coax cables that run to the satellite hut on the roof. They're fed from a regular air compressor which pushes the air through a multi-stage dryer, since the whole point is to prevent moisture ingress. The coax itself is about 3cm thick, and a complete bastard to handle. Luckily we installed it while the building was under construction. The top floor was completely empty so we could unspool the cable and figure 8 it to feed down the comms riser to our server room, then push the other end up to the roof.
LOL. Clive is a different kind of addict. He doesn't snort the "Normal" powder. He goes straight for the thermal fuse powder for that heated experience. Oh yes. XD
I've been working in the commercial field for refrigeration for many years. I believe that would be a "defrost Terminator"using the thermal disk terminate the defrost cycle and start the timer again for the next defrost cycle and if the defrost trimmer sticks on and that thermal desk doesn't cut the power thermal fuse will cut the power before your refrigerator burns up, those heater coils are like the coil in a oven.
Hey Clive . I gotta say I appreciate All of your videos . You obviously know what is what Re: electronics . 👍. Cheers mate , that Sodastream video got me thinking . Excellent content . 👴🧐🤔👍👍👍
"Do not taste the white powder on the table" LMAO point taken, Clive. But the sliding contact fuse is also kind of new to me, good one ! Fascinating channel!
Fun fact, the little thermal fuse is commonly inside of toasters, if the plug area gets too hot that fuse blows, toaster stops working. I recently replaced mine with a thermal breaker to keep the protection but allow it to reset as needed.
You could definitely have some fun with an x-ray machine ... they used to be ubiquitous in shoe shops when I was a kid. I remember putting a tanner in my sock just so I could see it ! Got told off as it was ever so slightly obvious to the grown ups...lol
Clive, there's a video here on YT that does a teardown of a thermal fuse if you want to see more details. It's called Thermal fuse (how it's made). He came up with a similar response to yours.
Are the wires that get the hermetic seal treatment stranded or solid core. If it is a solid core then the plastic coating will make a nice tight fit but the stranded would need the sheath to melt through all those strands to make it airtight. I'm better the wires are solid core for that reason. Would be nice to find out one way or the other. This assumes there have been no cable coating breakthroughs since I worked in the cable making factory many, many short years ago.
Some oxygen (lambda) sensors use the space between the braided wires for the reference air side. These work through crimps, waterproof connectors, and provide better protection from moisture. Critically, you cannot solder the connections or use dielectric grease in the waterproof connector or they won’t work. They don’t need much air. So my guess is that plastic weld leaks very slightly through the braided wires, unless they’re soldered or oiled on one side.
3:04 i wrap thermal fuses in paper rug soaked with water and i can solder them really nicely and they don't trip. I fix automotive resistor modules like this, typically with 180 deg C fuses. I if would fix in example water heater with 105 deg C fuse i would use alcohol soaked rug
Did you ever teach? Your voice (As I have said in the past, is very relaxing) and the way you explain things (With the help of the drawings) is amazing. Then again, you will probably reach far more people on here. Either way, I always enjoy your videos mate. Thank you.
Good explanation of the workings of thermal fuses. Thank you! Changed hundreds, but never cracked one open. How about for a #short playing with a hot air gun and the bimetallic disk on a desk top. Ought to dance nicely.
interesting on the thermal fuse. so that plug dust should melt at around 75c then. I wonder what it is? Now I am wondering if one time trip bi metalic ones just over distor to the point of no return or also have some special melty stuff in them??
What's it taste like ? lol I used to repair defrost timer Thermostat's fans Never thought about opening one of those Now I'm curious to know what's inside static fuse in back of the dryers In the Kenmore ?
I had a refrigerator that used to pop and crack loudly in defrost mode then it would ether freeze or defrost every thing changed the timer twice and the thermostat and relay the noise was normal they told me after a month of this it got scrapped . When I went to replace it the sales gal told me no matter what you buy it will last about 7 years no matter if it’s one that cost 2Kor just $300 sad my old one was still working but was a manual defrost Philco I’d had owned it over 30 years I gave it to a work buddy 10 years ago and it’s still going strong !
I've been enjoying your channel Clive since i found it, electrical is fundamental part of modern tech. How does an amateur like me learn about PCB basics and their design. I've an understanding of the physics but am curious on how a system is designed? From your other videos, a reverse engineering investigation shows you can do an objective many methods like in computer programming. How do these items get designed (especially to a best practice?). Cheers
Plastic heat crimpers run at a steady temp. It is the duration that varies. A similar pink plastic that is heat crimped and waterproof is the sodium chloride solutions for inhalation.
So... That powdery stuff could be a flux of sorts? Set to melt at a specified temperature to meld and be a soft giiy mess that the stronger spring is pushed into when the fuse "fails"?
Electric blankets have a similar type of thermostat in them, and the way they're made, the may have as many as 3 or 4, with 1 for each temperature setting. They are sealed so that the blanket can be laundered, and also to protect from sharp edges that could poke through the blanket.
Is the PB short for Polybutylene? Though that looks more like clear PVC if I had to guess otherwise. If there's possibly a #3 recycling mark, that would designate it as PVC.
I remember those thermostat bumps in older electric blankets to keep hotspots from forming and catching fire. Problem when you powered up a wadded/folded electric blanket without them every few feet along the heater wire.
The package has been RF welded. welded using radio frequency energy. yes it will probably seal the wire as well (as long as the covering is pvc) I know I repair the machines
@@UberAlphaSirus a "hot bar" could burn the pvc and still not provide a hermetic seal. The time the bar would be in contact would be very critical, too much or too little could ruin the item. RF welding is better for that sort of job. You'd be surprised how many things are RF welded. Just go to B&Q and have a look at all the sealed clear packs .. they're a bitch to open but it stops people messing about with stuff while letting them see what they are getting
@@davestewart2359 I don't see why a "hot bar" would burn PVC unless it was set to max. Why it would not create a hermetic seal. Can you use RF to impresion serial numbers on the other end of the capsule. And would the copper conductors interfer with the RF energy? Just some intrested queastions, no mallace intended.
@@UberAlphaSirus ok ..... Direct heat is very difficult to control. It takes time to transfer through the material, so while the inside is still solid the outside has already melted. Sometimes there are molecular changes that go on due to the heat and the material becomes brittle. Conversely with RF welding the tool is "cold", the heat is generated inside the material (a little like a microwave). The applied energy needs only to be on for a few seconds and the whole of the material where the tool is in contact becomes molten. Yes you can imprint text as you are welding, the tool needs to be designed for it though. Finally, yes, having wires poking out is not a good idea, but as long as the tooling and the process is properly designed, there "shouldn't" be any problems. Though accidents do happen. I remember working on a machine where thin steel backplates were encapsulated in the spine of a binder. The plates had to be placed perfectly as there was only about 1mm space all around. If the tooling hit the steel plate there would be a hell of an "arc" which would burn a hole in the upper tool AND the base causing a few hours downtime.
@@stepheneyles2198 I bought engineer ph-55 and ph-57 scissors from ebay couple years ago. I don't know who the hand model for those was, as it actually hurts to use them. Or I have been spoiled with classic fiskars handles here in finland, where fiskars has been THE scissor brand since the sixties and basically everyone has them on their kitchen. I bought those engineer ones just because I wanted to know if i have been brainwashed to use Finnish brand and to see if Japan would give us better tools, but it seems to be pretty hard to reach for the green ones, when my orange scissors are available. I'm not sure if the blades are any sharper/harder/whatever, as it does not matter if I would not want to touch the handles.
So can you take an old refrigerator that no longer gets cold. Bypass the over temp protection. And have a low temperature cooker. I wonder what temperature you could get it to. And would it melt the plastic pieces inside.
I've done something similar with my rc airplane/drone components with heat shrink tubing and a hot glue gun. The hot glue shrinks and seals it all nicely
I do this too, I buy the glue lined heatshrink and once hot I use an old set of heavy pliers to cold crimp the open end, then at the wire end pump in hot glue and reheat so it looks like it's been potted around the wires.
Clive or anyone in the know… I have a device with a .01 ohm current sense resistor. The actual circuit serves as an on/off switch that has a display that shows battery voltage, and automatically cuts out at lvc for Lipo battery packs. The oled display doesn’t show current. I replaced a fan that adds a tiny bit more current draw to the circuit and the stm chip cuts out and shuts down after showing an overcurrent error. If I raise the value of that .01 ohm resistor to decrease the voltage drop, would that be enough to run the higher output fan. The old fan was rated at .25a the new one is .75a. My thought is this may mess with the low voltage cutoff…
Still at the robot repair shop. :-] "Ahahhh... I finally figured out what's wrong with Grandpa's thermostat." @:-) "Oh. What is it?" :-] "Well. After 50 years of dribbling down his leg, it fused the contacts together." 8o]~~
I like how that waterproof package is basically exactly the same concept and construction as glass envelopes for light bulbs and vacuum tubes, just done with plastics instead of metal and glass.
Yep and single dose suppositories and those little ammonia packets you snap to wake somebody up as well..
@@Z-Ack very cool stuff. It's funny how when he started thinking about how the wires are crimped together I was like" this is so interesting!" Probably to only like 5 people! But turns out it's a bit more than 5 :)
Makes me wonder when we will see a renaissance of tubes, but flexible ones
The pooploop has been completed.
I thought it looked like a tube for toothpaste, myself.
Well, that thermal fuse design explains why i keep seeing these getting intermittent!
At work we use them in gas reactor tubes that abate gases coming from semiconductor production tools. 184°C fuses. A column that has shut down will often be resetable once it has cooled down, but will turn off after half an hour, and the fuse would still read continuity when you arrive there.
That's one of the many traps for young players. Change that fuse based on its paint burned up, not from what the meter tells you :p
Clive, thanks for the video. That is a super low cost defrost bi-metal switch. Definitely not hermetic, as moisture can migrate through that plastic. This design is a step backward, the previous versions clip onto a pipe on the evaporator to sense temperature so, this design will have thermal lag.
The "N12-5" number lists the cut-out and cut-in temperature, although with that number, there should be either a F or C suffix which denotes Fahrenheit or Celsius. In the number, the 12 is the cut-out (or open) temperature, most likely in Celsius. The -5 indicates the switch will close 5 degrees below the cut-out temperature. So, the switch will open at +12C and close at +7C degrees as marked.
Originally, with "frost free" refrigerators, the defrost cycle was controlled by a motorized timer switch. Since the 1990's, the defrost is controlled by an electronic circuit that makes the decision to defrost based upon the amount of time the compressor runs and the number of door openings. When defrost is activated, it turns on a (typically) 600 watt heating element that is connected to the bottom of the evaporator coil, which runs for 10 - 20 minutes. After the defrost cycle ends, the refrigeration has to remove all of that heat. The defrost algorithm doesn't take into account relative humidity in the room or makes no determination if the ice is actually melted on the evaporator so, in addition to using electric resistance heat (versus heat pump mode), it wastes a lot of power.
There's something quite lovely about these sorts of things that are low cost but very highly engineered.
indeed.. : )
Nice vid Clive. I often encapsulate small modules in clear, glue lined heat shrink, I crimp the ends whilst it's still hot, then pump in hot glue in the wire end, re-heat and it's almost potted. Have loads of IoT modules around the house done like this.
In a world where everything seems to have been simplified down to just be some chip or discrete sensor, it's always funny to me to see things like that thermal fuse that are sorta like some medieval contraption but with electricity
Safety devices should be as simple and reliable as possible. Springs opening contacts, energy loss shutting down devices, gas pilot lights with automatic shutoffs, etc.
Thanks! I could have sworn I'd seen that somewhere.
It's medieval stuff like these that save your house from burning down!
The design of the thermal fuse is really quite surprising. I also did an autopsy a fuse like this from a broken iron and I wasn't smart about it, so thank you for the helpful information.
Speaking of irons and thermal fuses.
This I think was an older model but don't know for sure.
I was scrapping an iron for a few things and also use the base/ soul of the iron as a weighted base for something else for a tool Mount I think it was it may have been I was using it to make a soldering iron holder for someone!
But the thermal fuse in that iron was something well rather intriguing.
It was not standard little cervical thermal fuse like the one in this video was.
It was essentially to contacts brass or copper alloy or other that that a bit of a spring to it.
There were two circular portions of the contacts that were essentially soldered with a low melting point alloy.
And that was the thermal fuse itself!
Also I was working on an old movie projector which I wound up salvaging in the end once it died!
The Intriguing thing is the internal Motors were actually 240 since this was originally built in Europe.
However the power transformer was designed for use with world voltages.
So this Transformer also acted not only as the lamp Transformer and a step-down Transformer but also a Step up Transformer!
And when I was in there trying to check some voltages I got a nasty surprise happened to bump the terminal on the Transformer they're like whoa that's more in line voltage turns out I I had received a 500 volt shock!
So I put it like that that's designed for multiple countries and is produced in Europe be careful that's not something I expected in the least and because it was so dark inside of it it was difficult to see and almost no terminals were labeled besides the input selection terminals for line voltage selection.
No mention of very high voltage or whatever inside you think there would be some sort of warning when that voltage is present!
And yes it was being powered from 120 volts here in the US!
The other interesting thing is instead of a fuse or even a thermal fuse this may have been used for both simultaneously possibly.
It had what I would describe as an open link fuse with a spring hooked on one end of the s-shaped hooks of the fuse element.
Essentially a low melting point elderly attaching to pieces of either copper or other metal alloy.
Essentially two pieces of metal and solder was the actual fuse!
And fairly strong extension spring!
Not sure if this was intended to be blown by current or heat or both but I suspect both.
Also I'd seen something similar to that iron thermal fuse but on a smaller scale inside of some old hair dryers every once awhile but not very often mostly very early ones probably wasn't the best idea to take those apart since their mind have been asbestos!
But those hair dryers continued to dry hair!
This is long before modern hair dryers but still looked like someone the modern ones back when they were just the two prong cord and no fancy gfrc and ionic whatever where all you had was on off cold high low medium that's about it.
Later on they would add a diode to do away with one of the heating elements essentially feed half-wave rectified to the heating element to reduce element power output.
Much like the old Radio Shack dual heat soldering irons more old school hi low dimmer switches.
I'm wondering if there's anyone that makes a night light fixture that has a diode in series with the socket to increase lamp life and dim it quite a bit as well of course incandescent and this needs to be for 120 volts ac for United States as well!
I know when option would be a nightlight size and wattage bulb that would be something like a 220 volt indicator in place of the steering night light bulb but that's harder to find but they do exist probably costly to get potentially as well
I've seen hundreds or these fuses and never knew how they worked-thank you. THIS EXPLAINS WHY I KEEP GETTING CALLS FOR THESE FUSES BLOWING IN WALLOVEN. for some reason they have put these behind the controls of whirlpool wall ovens and if a customer leaves the oven door open too long it blows 👍🤙
@@gags730 the one with the appliance Manger board and the dsi (direct spark ignition) board for the oven?
@@gags730 that's the plan. Planned obsolescence and intentional murder of the repair market. It's sabotage. It's "products as a service". It's "sustainable income". It's a weapon to kill human prosperity and replace it with turning humans into bags of meat - tax cattle. Unfortunately, trying to explain to a meatbag that they're a meatbag doesn't work. Oh well, not a loss, they ARE meatbags.
No broiling allowed.
lazy design engineers; providing work for thousands of installation/repair techs the world over
@@frogz they're not lazy, it's intentional.
Interesting bit on the fuse. I always figured they were made with a fine wire with a low melting point.
Low temp alloys would not have the mechanical properties to be draw into wire. It is usually a button or a plug. Honestly the best you could hope for is a tensile of 5k psi with an sn/bi eutectic. The rest are drastically less.
*drawn
These things often have to conduct the whole current in series with a line voltage (120/230/240V) heater element or heat pump compressor, so you can't really make the wire that fine.
I'm working on a device that needs wires to exit a sealed pouch so I'm interested to see a commercial application. Air does indeed leak down multicore wire, and I guess moisture could also wick the same way, so I'd hope the heat-sealing overcomes that. In my case, I've used enamelled wire rather than stranded to avoid the problem.
A good high temp wire is coated in silicone and woven fiberglass.
Maybe silicone at the end of the insulation.
I have done something similar in the past with success. I use solid core wire and strip the insulation off the wire, then heat seal. Same premise as what’s shown in the video, but with solid core wire and no insulation at the point of the heat seal. Obviously it’s important to stop adjacent conductors from touching while heat sealing, but it hasn’t been an issue for me yet.
Yes, things can wick down a stranded wire. I have had batteries leak and found the corrosion wick like 6 inches down the wire finding green corrosion the other end.
I've worked with a sensor that had to be waterproof, but had a connector at the end of 20cm of stranded wire. We used "sealed" wire, which had small blobs of silicone sealant added to the strands every two cm or so. That makes the wire more expensive, of course, but it did a good job of preventing moisture from moving down the strands.
Had to have a look and found there are 3 main types of thermal fuse. the sliding contact like the one you had and two with a form of low melting point wire and resin. then the wire melts it forms two balls on end of the broken wire. the resin helps with the balls forming due to surface tension on the molten wire and also to form a insulation gap between them. Used them a lot but never thought about how they worked, just about what temperature they will trip at. Used to solder a few but used pliers as heatsinks to stop them tripping from the soldering. Always a nice little addition to the side of a mains transformer. Or if you want to keep the repair bills up a bit inside the transformer. 🙂
I like when you don't pause and show us the whole process! Few people show what it takes to open or even repair something that seems trivial such as opening that sealed sensor. I find the entire process from beginning to end interesting, it's like a "mental rep" of me following along with my eyes as if I was doing so myself. Love this videos keep it up!
Hey Clive! You did, in fact, already open one of those thermal fuses. It was in one of the older heater videos (Like the pink one, the blue E27-type one and the Clothesdryer one)
I had to do a post mortem on equipment that had a thermal runaway. The factory it was located at suffered a power surge due to a lighting strike and as a result the solid state relay controlling the heater shorted out causing an over heat condition. A thermal fuse would have been the last defense against runaway but the surge cause the thermal fuse to explode and the center pin became welded to the case. Eventually the equipment got so hot that the wire nuts in the solenoid valves, located in the insulation space, started melting and exposed the metal inside which came in contact with the case of the solenoid junction box causing the control circuit fuse to blow which opened the heater contactor.
i'll bet anyone who witnessed it happen will never forget the dull orange glow of the heater before it blew
Wow, that was really interesting.
Imagine being on the design team for that thermal fuse.
That tiny thing is very clever and easily overlooked.
That's interesting, but brings back bad memories. My fridge was having some issues recently and while trying to fix it I stupidly touched the defroster element while it was running to see if it was working. For some reason I thought: it just needs to melt ice, it can't get that hot. Well I got incredibly painful second degree burns on three fingertips in about half a second. Protip: Don't touch the defroster. That fridge is now in the junkyard.
Heh! Blame the fridge why don't you?
Not glowing=/=Not hot is a lesson we all learn at some point.
Fantastic video. As a former home appliance tech, i have replaced that type of defrost stat more times than i can remember. Lots of fun to -see- the insides, not just know how it works. You nailed the explanation of how the timer works as well. A treat too, to learn and see more about the fuse pal, always a pleasure. Thank you kindly!
Wow, the thermal fuse is fascinating! Such a brilliant design!
Just proves I have to watch every single one of your videos, always. I've always wondered what was inside a thermal fuse, and there it is...
Good info, I assume that what might appear to be a minor dent on one of those thermal fuses could in fact completely DISABLE/JAM the internal sliding contact break operation!
Struth, who would have expected that minor thermal fuse case damage is potentially dangerous?
Maybe this vulnerability needs a bit of research & publicity to avoid electrical fires?
Thoughtful Moment .... I nearly had a serious house fire a few years ago when a (new but mostly plastic) fan heater was found to be burning furiously in a briefly vacated room. (luckily smoke alarm went off). I couldn't work out why the thermal fuse must have not tripped until after the heater was well alight. I didn't look for dents in the fuse's case.
yes the thermal fuse is working like that, this "compound" or wax stuff or whatever it may be made of has a certain melting point which is melting letting the contacts slide away from each other. it is actually pretty common fuses like this goes open over time even if they don´t pop. soldering them can be a hassle but it is possible even with the 70 degree ones. when I do solder i use freeze spray to frost the fuse body and use a very high temperature on the iron to as quick as possible solder the ends of the leads to the device, wires or PCB and then cool down the legs with the spray before the heat goes into the fuse. it may also work to hold the lead tightly with a thick plier while you do, it depends on the rated temperature of the fuse
I absolutely love that packaging! Now I'm gonna have to figure out how to do that. Hmmm....
If the plastic cover is the same material as the wire insulation it should not be that hard...no reason it would hurt the wires, it could expose copper, but then it would still be covered in melted plastic. I wonder if I could use a modified impulse sealer with some notches for wires.
Oooo....then you could inject the entire thing with hot glue or silicone.
So that's how thermal fuses work! You've answered a question that nagged at me for twenty years and the post mortem of more than a few of them.
thank you for the diagram of the thermal fuse, i've broken plenty of these but i've never investigated further than a tertiary glance at these and never had enough inclination to pull up a patent or anything
These exist for one reason because the thermal barrier to the thermal fuse and when you get massive condensation in a humid environment. The original designs only had one sensor in the fridge or evaporator so there was no software fix to stop it blowing the fuse, the thermal switch allows it to cycle the defrost system and hopefully get it all done before the end of timer. What might be interesting to explore is just how good an insulator ice can be in these situations where you have a defrost system running and parts of the system cooking and the the ice can shield parts of the controller system, its a minefield.
For that fuze - now that you know what the guts of it looks like, get another one and deliberately blow it, then cut it open to see what happened. The functionality will become apparent.
I've been in high tech for 32 years now and am rediscovering the tiny component stuff thru you - it's refreshing and tremendous fun. :-)
Speaking of passing air through wires, at work we have pressurised coax cables that run to the satellite hut on the roof. They're fed from a regular air compressor which pushes the air through a multi-stage dryer, since the whole point is to prevent moisture ingress.
The coax itself is about 3cm thick, and a complete bastard to handle. Luckily we installed it while the building was under construction. The top floor was completely empty so we could unspool the cable and figure 8 it to feed down the comms riser to our server room, then push the other end up to the roof.
Always wondered how those type of thermal fuse worked, very interesting.
Reason for crimping !! Makes perfect sense, thanks Clive
That little thermal fuse was designed by a devious mind!
LOL. Clive is a different kind of addict. He doesn't snort the "Normal" powder. He goes straight for the thermal fuse powder for that heated experience. Oh yes. XD
Speaking of cost engineering, can we just take a moment to appreciate that this video is precisely 10 minutes long?
Oh nice love fridge related Video it's simple but so much efficient
Very cost engineered... well put
I've been working in the commercial field for refrigeration for many years.
I believe that would be a "defrost Terminator"using the thermal disk terminate the defrost cycle and start the timer again for the next defrost cycle and if the defrost trimmer sticks on and that thermal desk doesn't cut the power thermal fuse will cut the power before your refrigerator burns up, those heater coils are like the coil in a oven.
You make this world so interesting, man!
"Let's cut all the wires."
I wouldn't recommend you getting a job in bomb disposal. 😁
Interesting take on thermal fuse.
Hey Clive . I gotta say I appreciate All of your videos . You obviously know what is what Re: electronics . 👍. Cheers mate , that Sodastream video got me thinking . Excellent content . 👴🧐🤔👍👍👍
Thanks from Texas Clive
"Do not taste the white powder on the table" LMAO point taken, Clive. But the sliding contact fuse is also kind of new to me, good one ! Fascinating channel!
"This is where a sharp pointy object can be used to stab fingers."
Too true, lol!
Oh i learned something too about those thermal fuses! Thanks for digging in to one and explaining it in your usual clear manner! :D
Fun fact, the little thermal fuse is commonly inside of toasters, if the plug area gets too hot that fuse blows, toaster stops working. I recently replaced mine with a thermal breaker to keep the protection but allow it to reset as needed.
4:08 - "... occasionally checking the screen to ensure I am on the shot" says Clive as everything disappears out of the bottom of the frame. :-P
I was waiting for you to put it back together.
Awesome video big Clive
You could definitely have some fun with an x-ray machine ... they used to be ubiquitous in shoe shops when I was a kid. I remember putting a tanner in my sock just so I could see it ! Got told off as it was ever so slightly obvious to the grown ups...lol
With that clicky bit i momentarily thought Mr Clive had gone ASMR on us 🤣
My guess, based on the thickness, on the outer plastic is some strong polymer that heat binds the ends strongly together.
Nice scissors ✂️!
Looks very PVC-ish.
Clive, there's a video here on YT that does a teardown of a thermal fuse if you want to see more details. It's called Thermal fuse (how it's made). He came up with a similar response to yours.
Are the wires that get the hermetic seal treatment stranded or solid core. If it is a solid core then the plastic coating will make a nice tight fit but the stranded would need the sheath to melt through all those strands to make it airtight. I'm better the wires are solid core for that reason. Would be nice to find out one way or the other.
This assumes there have been no cable coating breakthroughs since I worked in the cable making factory many, many short years ago.
Some oxygen (lambda) sensors use the space between the braided wires for the reference air side. These work through crimps, waterproof connectors, and provide better protection from moisture.
Critically, you cannot solder the connections or use dielectric grease in the waterproof connector or they won’t work. They don’t need much air.
So my guess is that plastic weld leaks very slightly through the braided wires, unless they’re soldered or oiled on one side.
Kewl! Thanks Big Clive.
Thank goodness we got the doodle at the end of the video.
Very clever fuse design.
3:04 i wrap thermal fuses in paper rug soaked with water and i can solder them really nicely and they don't trip. I fix automotive resistor modules like this, typically with 180 deg C fuses. I if would fix in example water heater with 105 deg C fuse i would use alcohol soaked rug
Pretty cool man! I never thought about a thermostat for defrost, I’m not in the appliance/reefer/freezer game though
Engineer scissors are the best. I have a pair and they cut everything with ease. (Apart from wires obviously, got Knipex cutters for that)
Did you ever teach? Your voice (As I have said in the past, is very relaxing) and the way you explain things (With the help of the drawings) is amazing. Then again, you will probably reach far more people on here. Either way, I always enjoy your videos mate. Thank you.
Yes, more on thermal fuses please.
4:09 - Comments about checking to stay in shot, immediately goes out of shot
That cracked me up way more than it probably should have 🤣
Good explanation of the workings of thermal fuses. Thank you! Changed hundreds, but never cracked one open.
How about for a #short playing with a hot air gun and the bimetallic disk on a desk top. Ought to dance nicely.
I never knew that thermal fuses worked like that, I'd have never guessed it either. 👍
interesting on the thermal fuse. so that plug dust should melt at around 75c then. I wonder what it is? Now I am wondering if one time trip bi metalic ones just over distor to the point of no return or also have some special melty stuff in them??
I see the waterproof package is make of PINK plastic... Very tasteful.
That Peking Duck has been in your freezer to long anyway! Good luck 👍
What's it taste like ? lol
I used to repair defrost timer Thermostat's fans Never thought about opening one of those Now I'm curious to know what's inside static fuse in back of the dryers
In the Kenmore ?
Well...as you said: "Good stuff"👍
Between admiring the engineering and fidgeting with the bimetallic disc I'm sure there's an hour of entertainment in one of these for me. 😅
I had a refrigerator that used to pop and crack loudly in defrost mode then it would ether freeze or defrost every thing changed the timer twice and the thermostat and relay the noise was normal they told me after a month of this it got scrapped . When I went to replace it the sales gal told me no matter what you buy it will last about 7 years no matter if it’s one that cost 2Kor just $300 sad my old one was still working but was a manual defrost Philco I’d had owned it over 30 years I gave it to a work buddy 10 years ago and it’s still going strong !
I remember replacing a thermo fuse on a coffee maker. It was back in the 80's.
@7:15... shouldn't lick fingers... lol ... interesting little tear down. Like the extra at the end, very cool.
I've been enjoying your channel Clive since i found it, electrical is fundamental part of modern tech. How does an amateur like me learn about PCB basics and their design. I've an understanding of the physics but am curious on how a system is designed? From your other videos, a reverse engineering investigation shows you can do an objective many methods like in computer programming. How do these items get designed (especially to a best practice?). Cheers
good stuff indeed, thank you
Plastic heat crimpers run at a steady temp. It is the duration that varies. A similar pink plastic that is heat crimped and waterproof is the sodium chloride solutions for inhalation.
For some reason when you cut it open, I expected it to be filled with a gel of some sort... Also very appropriate choice in color :)
4:40 I can be wrong, but i guess it's ultrasonic crimped.
So... That powdery stuff could be a flux of sorts? Set to melt at a specified temperature to meld and be a soft giiy mess that the stronger spring is pushed into when the fuse "fails"?
Electric blankets have a similar type of thermostat in them, and the way they're made, the may have as many as 3 or 4, with 1 for each temperature setting. They are sealed so that the blanket can be laundered, and also to protect from sharp edges that could poke through the blanket.
Is the PB short for Polybutylene? Though that looks more like clear PVC if I had to guess otherwise. If there's possibly a #3 recycling mark, that would designate it as PVC.
That bimetallic disc seems to use the same principle as a Belleville washer. Nice.
I remember those thermostat bumps in older electric blankets to keep hotspots from forming and catching fire.
Problem when you powered up a wadded/folded electric blanket without them every few feet along the heater wire.
I found a lot of images: Mettler Toledo PB302 scales, some valves, power banks, blenders, a thermostat and even a paper PCB by this query.
Hmmmm! ;D
The package has been RF welded. welded using radio frequency energy.
yes it will probably seal the wire as well (as long as the covering is pvc)
I know I repair the machines
why would they use RF rather than a hotbar? What's the benifit?
@@UberAlphaSirus a "hot bar" could burn the pvc and still not provide a hermetic seal. The time the bar would be in contact would be very critical, too much or too little could ruin the item.
RF welding is better for that sort of job. You'd be surprised how many things are RF welded. Just go to B&Q and have a look at all the sealed clear packs .. they're a bitch to open but it stops people messing about with stuff while letting them see what they are getting
@@davestewart2359 I don't see why a "hot bar" would burn PVC unless it was set to max. Why it would not create a hermetic seal. Can you use RF to impresion serial numbers on the other end of the capsule. And would the copper conductors interfer with the RF energy? Just some intrested queastions, no mallace intended.
@@UberAlphaSirus ok ..... Direct heat is very difficult to control. It takes time to transfer through the material, so while the inside is still solid the outside has already melted. Sometimes there are molecular changes that go on due to the heat and the material becomes brittle.
Conversely with RF welding the tool is "cold", the heat is generated inside the material (a little like a microwave). The applied energy needs only to be on for a few seconds and the whole of the material where the tool is in contact becomes molten. Yes you can imprint text as you are welding, the tool needs to be designed for it though. Finally, yes, having wires poking out is not a good idea, but as long as the tooling and the process is properly designed, there "shouldn't" be any problems. Though accidents do happen. I remember working on a machine where thin steel backplates were encapsulated in the spine of a binder. The plates had to be placed perfectly as there was only about 1mm space all around. If the tooling hit the steel plate there would be a hell of an "arc" which would burn a hole in the upper tool AND the base causing a few hours downtime.
@@davestewart2359 thanks. Sounds like I will have to look into it more.
White powder on the table? Sounds like a good time!
SNAP ! I bought a pair of those exact scissors last week - so far they have been awesome. I might have a penchant for Japanese tools :)
Can you give us a clue as to where they're available? They look well-made...
@@stepheneyles2198 I bought engineer ph-55 and ph-57 scissors from ebay couple years ago. I don't know who the hand model for those was, as it actually hurts to use them. Or I have been spoiled with classic fiskars handles here in finland, where fiskars has been THE scissor brand since the sixties and basically everyone has them on their kitchen. I bought those engineer ones just because I wanted to know if i have been brainwashed to use Finnish brand and to see if Japan would give us better tools, but it seems to be pretty hard to reach for the green ones, when my orange scissors are available. I'm not sure if the blades are any sharper/harder/whatever, as it does not matter if I would not want to touch the handles.
So can you take an old refrigerator that no longer gets cold. Bypass the over temp protection. And have a low temperature cooker. I wonder what temperature you could get it to. And would it melt the plastic pieces inside.
I'm not sure what temperature it would get to, or if the plastic would deform.
The next time I replace a fridge I’m definitely going to test this on the old one. Maybe I should video it incase it bursts into flames. :)
Have you ever come across one of these thermal switches that used a mercury switch instead of dry contacts?
Are many fridges that aren’t frost free sold anymore? I haven’t seen a fridge that needs a defrost cycle in years.
Clive, what're your thoughts on those Engineer scissors? I keep thinking about grabbing a set...
They're pretty handy.
I've done something similar with my rc airplane/drone components with heat shrink tubing and a hot glue gun. The hot glue shrinks and seals it all nicely
I do this too, I buy the glue lined heatshrink and once hot I use an old set of heavy pliers to cold crimp the open end, then at the wire end pump in hot glue and reheat so it looks like it's been potted around the wires.
Yes, good stuff. 👍
Can you make a short where you freeze the bi-metallic discs to see if they go snap?
Now that was cool to watch. thermal breaker fuse. very well though out...no? DVD:)
It reminds me of the thermostat that's used with those pipe heater tapes...
Clive or anyone in the know… I have a device with a .01 ohm current sense resistor. The actual circuit serves as an on/off switch that has a display that shows battery voltage, and automatically cuts out at lvc for Lipo battery packs. The oled display doesn’t show current. I replaced a fan that adds a tiny bit more current draw to the circuit and the stm chip cuts out and shuts down after showing an overcurrent error. If I raise the value of that .01 ohm resistor to decrease the voltage drop, would that be enough to run the higher output fan. The old fan was rated at .25a the new one is .75a. My thought is this may mess with the low voltage cutoff…
Big fan of your work! Any way to get a defibrillator and the human heart as a circuit with schematic and all? Maybe a boom for fun? 😉
I replaced one in my fridge this year and fridge works perfectly saving lots of money but not sure how it works ;-)
Still at the robot repair shop.
:-] "Ahahhh... I finally figured out what's wrong with Grandpa's thermostat."
@:-) "Oh. What is it?"
:-] "Well. After 50 years of dribbling down his leg, it fused the contacts together."
8o]~~