In modern electrical appliances, fuses are found everywhere, or, to put it scientifically, fuses. They protect the network and the device itself from short circuits or overload. The design of fuse links is very diverse, as are the sizes. The rated currents and voltages for which fuses are issued correspond to standard values. Its overall dimensions, namely length, depend on the rated voltage of the fuse; the higher the rated voltage of the fuse, the greater the distance between the contacts. The rated current is determined by the cross-section of the wire inside the fuse.
Although self-resetting electrical fuses can now be found in more expensive devices, most devices are still equipped with conventional fuses.
General concepts, introduction to tubular fuses
The most common fuses are the so-called tubular ones. They are a ceramic or glass tube with metal cup contacts at the ends. These cups are connected to each other by wire, the cross-section of which, as already mentioned, determines the rated current of the fuse. This current is indicated on the tube or one of the contact parts of the fuse. For example: F0.5A - this means that this fuse is rated for a current of 0.5 amperes.
On electrical circuit diagrams, a fuse is indicated by a rectangle with a straight line passing through it. Next to the conventional graphic designation its position designation is indicated, for example F1 (F – fuse, fuse in English); and if this does not clutter the circuit - the rated current, for example 100 mA.
Description of the operating principle of a fuse link (fuse)
The principle of operation of the fuse is extremely simple. When a rated current flows through the wire connecting the fuse contacts, this wire heats up to a temperature of about 70 °C. But when the current is exceeded, the wire heats up more, and when the melting temperature is exceeded, it melts, i.e. burns out. It is for this reason that fuses are also called fuses or fusible links. The higher the current, the faster the heating, the faster the melting occurs, and, accordingly, the fuse blows.
Thus, all fuse links operate on the same principle - excess current in the circuit causes overheating and melting of the wire inside the fuse and, as a result, disconnection of this circuit from the power source.
There are two main reasons for the burnout of fuse links: surges in the supply voltage and a malfunction within the electrical appliance itself.
Checking the fuse, fuse fault indicator
You can check the fuse-link with any continuity tester or tester. The goal is to ensure that the fuse circuit is intact and capable of conducting electrical current.
To avoid electric shock, checking the fuse is only allowed when the electrical appliance is turned off!
In addition, you can buy or make your own fuse blown indicator, which will notify you that the fuse has blown.
The circuit diagram of such a device is extremely simple and is shown in the following figure.
LED HL1 is connected in parallel to the fuse contacts, through current-limiting resistor R1 and diode VD1, to protect against reverse voltage. Diode VD1 must be selected based on the reverse voltage exceeding the mains voltage. For a 220 V network, the reverse voltage for the VD1 diode must be at least 300 V; for example, the 1N4004 diode or the domestic KD109B meets these requirements.
The indicator does not light if the fuse is good, and lights up if it is blown.
This circuit is very convenient to complement home-made power supplies.
By slightly changing (simplifying) the circuit, you can get a fuse blown indicator on a neon lamp, although it does not look as effective as an LED.
Selection of fuse according to the rated power of the electrical appliance
After checking the fuse and determining that it has failed, it must be replaced. And to do this, you need to find out its denomination in order to make the correct replacement.
If you know the power consumed by an electrical appliance, it is usually indicated on the nameplate of the device, you can independently calculate the rated current of the fuse using the following formula:
Inom = Pmax / Unom
The rated current (Ampere) is equal to the quotient of the maximum power (Watt) of the electrical appliance divided by the rated network voltage (Volt).
For example, a fuse in a TV has blown, it is not possible to make out what is indicated on the fuse body, its rating, but the power consumption of 150 VA is indicated on the TV nameplate.
150 / 220 = 0.68, rounded to the nearest higher standard value - 1 A.
Please note that when calculating the fuse current rating you are getting an exact current value which may not correspond to a range of fuse ratings. Therefore, the calculated value taking into account the 5% margin is rounded to the nearest standard value.
For simplicity, you can use a ready-made table that shows the ratings of standard fuses for various consumers based on their connection to a 220 V household network.
Replacing the fuse
When replacing a fuse, to avoid electric shock, be sure to unplug the electrical appliance!
There is an unspoken rule: if after the second replacement the fuse blows again, look for a fault in the electrical appliance itself. This means that the electrical appliance needs to be repaired.
Do not install a fuse at a higher current under any circumstances; such attempts will definitely lead to even greater damage to the device, up to the point of its being beyond repair!
Be careful when purchasing a new fuse. Correctly determine the type and current rating of the replacement candidate. It is better to purchase electronic components from trusted suppliers who guarantee product quality, such as Conrad Electronic. The full range of fuses can be found at the link - https://conrad.ru/catalog/predohraniteli_s_plavkoy_vstavkoy.
Fuse repair
Typical people believe that fuses cannot be repaired; in fact, this is not the case. Most types of fuses can be repaired and given a second, third, etc. life. The fuse housing, as a rule, is destroyed extremely rarely, the wire inside burns out, and the repair consists of replacing it. The main task is to use a wire similar to the one in the fuse.
If you need to replace a fuse very quickly, but you don’t have a spare at hand, you can use the following method:
Remove the paint coating from the wire (clean it until it shines) and wind several turns around each fuse contact, then insert the fuse into the holder. This method is popularly called “bug”. With its help you can very quickly check the serviceability of the device, but it is not reliable and can be used as a temporary solution to the problem.
The next method is the so-called “factory” one. Repairs will require a soldering iron, and perhaps a Dremel or screwdriver, but the fuse after repair will look like it came straight from the factory.
Heat the ends of the cup contacts with a soldering iron and remove the solder from the holes in the ends using a toothpick or something similar. It happens that the holes are too small or completely absent, then you will have to drill them. Use a drill of small diameter 1 - 2 mm.
Pass a wire of a suitable diameter through the holes and solder it to the cup contacts.
The fuse is ready!
Selecting the diameter of the fuse wire
As written above, to repair a fuse, it is necessary to replace the burnt wire with one similar to the one that was in the fuse before it burned out.
Factory fuses use wires made of various metals: silver, copper, aluminum, tin, lead, nickel, etc. At home, it is unlikely that we will be able to determine the material of the wire of a blown fuse, and we also have ordinary copper wire at hand. But just in case, we present a table of wire diameters depending on the rated current of the fuse, containing, in addition to copper, aluminum, steel and tin.
| Fuse current, A | 0,25 | 0,5 | 1,0 | 2,0 | 3,0 | 5,0 | 7,0 | 10,0 | |
| Wire diameter, mm | Copper | 0,02 | 0,03 | 0,05 | 0,09 | 0,11 | 0,16 | 0,20 | 0,25 |
| Aluminum | - | - | 0,07 | 0,10 | 0,14 | 0,19 | 0,25 | 0,30 | |
| Iron | - | - | 0,13 | 0,20 | 0,25 | 0,35 | 0,45 | 0,55 | |
| Tin | - | - | 0,18 | 0,28 | 0,38 | 0,53 | 0,66 | 0,85 | |
| Fuse current, A | 15,0 | 20,0 | 25,0 | 30,0 | 35,0 | 40,0 | 45,0 | 50,0 | |
| Wire diameter, mm | Copper | 0,33 | 0,40 | 0,46 | 0,52 | 0,58 | 0,63 | 0,68 | 0,73 |
| Aluminum | 0,40 | 0,48 | 0,56 | 0,64 | 0,70 | 0,77 | 0,83 | 0,89 | |
| Iron | 0,72 | 0,87 | 1,00 | 1,15 | 1,26 | 1,38 | 1,50 | 1,60 | |
| Tin | 1,02 | 1,33 | 1,56 | 1,77 | 1,95 | 2,14 | 2,30 | 2,45 | |
Calculation of fuse wire diameter
If you need a fuse for a current not listed in the table above, you can use the formula to calculate the diameter of the copper wire depending on the rated current of the fuse.
For low currents (using thin wire with a diameter of 0.02 to 0.2 mm), the formula is as follows:
d = Ipl k + 0.005
For high currents (when using wire with a diameter of more than 0.2 mm), the formula is as follows:
Where Ipl– fuse-link current in amperes, To And m coefficients depending on the conductor material can be determined from the following table.
Determining the diameter of the fuse wire
On factory coils, the wire diameter is indicated along with other parameters. What to do if the wire is taken from a piece of stranded wire? The diameter of the wire can be measured with a micrometer. But even if you don’t have a micrometer, you can use the old fashioned way - measure the diameter of the wire using a ruler or caliper. It may not be as precise, but for our case it is quite acceptable.
We take a ruler and wind 10 to 20 turns on it. The recommended winding width is about a centimeter. At the same time, we try to ensure that the coils fit as tightly as possible. We count how many millimeters our turns took and divide this number by the number of turns. It is not necessary to wind it on a ruler, if the piece of wire is short, you can use a pencil, screwdriver, lighter or any other object for winding. The main thing is that the turns are wound evenly and tightly.
For example, the width of the wound turns is 9 mm, with a number of turns of 20. Dividing 9 by 20, we find that the diameter of the wire, if we discard another 0.05 mm for the gaps between the turns, is approximately 0.40 mm. Using this wire it will be possible to restore a 20 A fuse. That's so simple and quite accurate!
And finally, a video demonstrating the burnout of the fuse link:
It would be a crime not to mention fuses here. Like other types of safety devices, they are designed to protect a section of the circuit from harmful surges in the supply current.
Fuses
A distinctive feature of such fuses is their obvious simplicity. The device is nothing more than a piece of wire of small diameter. The latter easily melts when the current exceeds a given threshold.
Of course, this method of protection has an obvious drawback - the reaction time (melting of the wire does not occur instantly). That is, it will not save you from short-term, but no less destructive, current impulses. But it is very effective in case of short circuits in the network or when the permissible load is exceeded.
The principle of operation is based on the thermal work that current does when passing through conductors (and voltage does not really matter here).
Amperage = Maximum permissible circuit power / Voltage
That is, the maximum current that a fuse in a 220 V power circuit must withstand at a maximum load of 3 kW is about 15 A.
Due to the fact that fusibility depends on many factors (diameter of the wire, heat-removing capacity of the environment, material from which the wire is made, etc.), most often the burnt element is changed according to ready-made calculations from the table below (for the most popular metals) .
Table 1
Fuses on relay
As mentioned above, fuses have a serious drawback - reaction time. In addition, the burnt element must be completely replaced (the wire or the entire fuse must be replaced).
An alternative might be to consider a relay.
One example of the implementation of such a scheme is below.
Rice. 1. Relay diagram
During a short circuit in the powered circuit, the current sharply increases, as a result of which the composite transistor (VT1 VT2) is turned off and all the voltage is applied to the first relay, which, as a result of operation, opens the second relay and the current remains only on the closed composite transistor.
The designated block is designed only for circuits whose supply current does not exceed 1.6A, which may be inconvenient for various tasks.
It can be modified a little like this.
Rice. 2. Redesigned relay circuit
The R4 rating is not specifically stated, since it requires calculation depending on the parameters of the powered circuit.
You can use the ready-made indicators in the table below as a basis.
table 2
Both of the above circuits are designed to operate only on 12 V power supply circuits.
Electronic fuses without relay
If your circuit supplies current up to 5A and voltage up to 25V, then you will definitely like the circuit below. The response threshold can be adjusted using a trimming resistor, and the response time can be set using a capacitor.
Rice. 3. Fuse diagram without relay
Due to the fact that the transistor can heat up under constant load, it is best to place it on a heat sink.
As an alternative implementation, but with the same principle.
Rice. 4. Scheme fuse without relay
An even simpler electronic fuse with a minimum of parts is shown in the diagram below.
Rice. 5. Electronic fuse circuit with a minimum of parts
If a short circuit occurs, the transistor is blocked for a short time. If the blocking is removed, but the short circuit remains, the “fuse” will trip again, and so on until the problem in the powered circuit is eliminated. That is, such a fuse does not require turning on or off. Its only drawback is the constant inclusion of a direct load in the circuit in the form of resistor R3.
Electronic fuse for 220 V
The electronic fuse circuits shown above can only operate on constant power circuits. But what if you need a fast-blow fuse to protect power on 220V AC circuits?
You can use the overload protection block diagram below.
Rice. 6. Overload protection block diagram
The maximum operating current of this circuit, made on a 7906 stabilizer, is 2A.
T1 is a TIC225M transistor, and
T2 - BTA12-600CW (replacement not allowed).
The following may be simpler alternatives for AC circuits.
According to research from insurance companies, 93% of car fires occur due to the use of low-quality car fuses and faulty wiring. Therefore, if you want to reduce the causes of fires to a minimum, monitor the condition of the wiring as closely as possible. Considering the invaluable role of fuses in the correct functioning of automotive electrical appliances, we decided to talk about them in today’s article. You can learn everything about fuses - their purpose, differences, and most importantly - how to replace fuses yourself.
1. The true purpose of fuses is to prevent short circuits in wiring.
The role of the fuse is to protect against short circuit currents and overload currents, and thereby prevent various types of breakdowns or fire.
For convenience, all fuses are collected in one or two blocks. The entire fuse block is responsible for the functioning of the entire system of electrical appliances, and each individual element is responsible for a specific device. In addition to those fuses that are included in the electrical circuit, there are also spare fuses on the block. The most commonly used fuses are plug-in fuses.
You can often find multiple-action thermobimetallic fuses in blocks. How they function can be understood from the name. Their design is also quite simple: two plates with silver ends; thanks to the elasticity of the plates, the contacts are constantly in a closed state. During short circuits, the bimetallic plate overheats and bends. The current will begin to flow through the plate again only after it has cooled and returned to its original position. As a rule, this type of fuses is installed on the headlight circuit.
Automobiles also use fuse designs in which the thermobimetallic plate does not return to its original position. At their base there is another additional button and a spring. In this case, the plate cannot bend on its own, because it is held in place by a spring. In order to make the mechanism work again, you need to press the button, which will allow you to release the spring.
Fuses differ in their rating, which is expressed in amperes. During production, manufacturers use plastic of different colors, thus they indicate one or another electrical conductivity rating. Below is a table of ampere rating to color, although shades may vary:
Often, car enthusiasts tend to troubleshoot the fuse box in a very simplified way. They place a metal object (“bug”) in place of the fuse, or wind wire instead of a blown fuse. In such situations, it should be understood that if, subsequently, the pseudo-fuses fail to operate, all the electrical equipment burns out, or even worse, a fire occurs in the car, then there will be no one to blame.
2. When do you need to replace fuses?
First you need to figure out when you need to replace fuses. If you notice that devices such as a fan, lamp, high and low beam headlights, fuel pump, climate control system or other devices in your car have stopped working, then do not rush to run to the nearest store and buy new equipment. Often the cause of problems with such devices is only a short circuit in the network, which makes it necessary to check the car fuses. And the price of the fuse itself is significantly lower than the prices of the above electrical appliances.
Since the fuse boxes in each car are located in different places, we will not indicate where to look for them, just remind you that Modern cars most often have two fuse blocks. One of them is located in the cabin, and the second is in the engine compartment. The interior unit is often located behind the unscrewing steering column panel, in the luggage compartment area, or under the seat. To make it clear which device this or that fuse belongs to, there is a marking diagram on the back of the case. The name of the devices or the corresponding icons are written on it.
First, you should familiarize yourself with the meanings of the markings. Fuse box diagrams for cars are different. As a rule, along with the operating instructions for the car, explanations for the diagrams for operating the fuse box are also provided. If you buy a used car, the details of the fuse box can be found on the website of the official representative of your car model.
For example, a Renault Megane car has the following markings on the fuse box:
"A"- an element of the fuse system responsible for the operation of the power windows;
"WITH"- heating system fan;
"D"- power windows on the rear passenger doors;
"E"- automatic hatch covers;
"F"- anti-lock braking system;
"G"- cigarette lighter, audio system, heated seats, glass and headlight washers, alarm system;
"N"- brake lights;
"L", "M"- power windows on the front doors;
"N"- is responsible for the operation of instruments located on the car panel, the multimedia system, and the adjustment of rear-view mirrors;
"ABOUT"- sound beep;
"R"- rear wiper;
"R"- climate control system;
"S"- sensor for changes in temperature in the cabin;
"T"- heated front seats;
"U"- locking all doors at the same time;
"W"- heated rear view mirrors.
Once you have compared the section of electronics that is supposedly out of order with the letter markings on the block diagram, it will not be difficult to find the fuse that has failed. Next, you need to make sure that the fuse is actually blown. Many people think that it is enough to remove the damaged fuse from the block and carefully inspect for the presence of a blown jumper. But in fact, a visual inspection is not enough, especially in situations where the fuse jumper has not lost its integrity, but the fuse still does not work. This can happen due to the oxidation of metal elements that are no longer able to perform their functions.
We can advise you on the most accurate method for checking the fuse. To do this, it is not necessary to remove the fuse from the socket. First, you need to turn on the failed circuit, be it lifts, headlights, horn, etc. Next, check the voltage at both terminals of the specific fuse. If there is no voltage at one of the terminals, this indicates that the fuse has blown. Therefore, such a fuse must indeed be replaced. This verification procedure takes a minimum of time, and the results are as accurate as possible. As you can see for yourself, it is not difficult to understand when a fuse needs to be replaced; now all that remains is to figure out how to do it correctly.
3. How to change fuses to prevent short circuits in your car?
Unfortunately, not all drivers are able to appreciate the importance of having a good fuse. And not everyone understands what needs to be done if the fuse has blown or melted. Therefore, we would like to offer you step-by-step instructions for replacing the fuse. But before you start replacing the fuse, you need to make sure that it is really blown:
1. Find the fuse box to which the allegedly burnt-out devices are connected.
2. Find the fuse connected to your electrical appliance. A diagram on the outside with markings will make it easier to find.
3. Remove the fuse from the block. This can be done using special tweezers. As a rule, they are sold in a set with a block system.
4. Inspect it carefully; if external damage is visible, then this element of the block undoubtedly needs to be replaced.
You can replace a blown fuse with a new one when it is available. You can buy a car fuse in almost any store, but it is much more difficult to buy a high-quality fuse. The word “high-quality” means a fuse that will not burn out in a matter of hours, much less cause a fire. Therefore, before making a purchase, take a close look at the appearance of the sample. The plastic should be smooth, the metal should not have changes in cross-section. If you have doubts about the quality of the purchased fuses, then before installing the purchase in the block, it is advisable to conduct a small test. You can do it like this:
1. First, buy another fuse - a spare one;
2. Tape wires to the metal ends of the fuse;
3. Connect one to positive, the second to negative;
4. A high-quality fuse should blow, a low-quality fuse will melt.
After installing such a low-quality fuse, the system in the car will also melt, and this, you know, what can lead to. After this, you can proceed to the main stage - replacement. To do this, you need to install a new fuse in place of the old one, but before that you need to familiarize yourself with the following nuances:
1. Before installing a new fuse, it is necessary to eliminate the cause of the short circuit. Otherwise, the new fuse will suffer the same fate as the blown one.
2. Automotive fuses are divided into three sizes: mini, medium and maxi. Each of them is assigned its own place in the mounting block.
3.
The rated current in the fuse must be greater than the rated current in the device. In the case when the ampere value is less, the electrical appliance will quickly burn out, and the fuse will not even have time to react.
4. The ampere designation can be determined by the color of the plastic case.
5. Fuses from the primary circuit series must withstand at least 0.1 seconds ten times the primary rated current.
6. The time-current characteristic of the load must be higher than the time-current characteristic of the fuse.
7. In no case should there be exposed wires on the fuse box in contact with the housing, as this will inevitably lead to a short circuit. After installation is complete, check how correctly all electrical components in your car work. A replacement can be considered successful if no problems arise with the operation of the equipment.
Proven over many decades, the best means of protection against excessive overloads of the electrical network are fuses that are installed at the input of current supply systems. Their design and principle of operation are aimed at timely disconnecting the consumer from the network, thereby warning him about equipment failure and the possibility of replacing the fuse.
Device, types and principle of operation
A fuse is an electrical switching device that is intended to disconnect a protected electrical circuit by opening it or destroying (burning, melting) specially designed current-carrying elements during the passage of high voltage current through them. Its main elements are the body, the fusible metal insert and the contact part.
The principle of operation is quite simple: if high voltage is supplied to the network, the insert, which is usually made of porcelain or fiber materials, melts. The insert is a mandatory element of all fuses; inside it there is an arc extinguishing device. All devices that are used to protect electrical installations can be divided into four classes:
Fusible protective elements are considered the most reliable and are relatively inexpensive. They are very easy to diagnose for serviceability. To do this, you just need to look at the part in the light - you will see whether the melt is intact or not. They are produced in a glass case. When using them, you don't even need to install transformers. Fuses according to their size are divided into micro, mini (14-15 mm), normal (18 mm) and maxi (34 mm).
To work in high voltage circuits, other types of protective mechanisms are used: gas, liquid. There are even shooters. Under normal conditions you cannot see them - they are very powerful equipment.
In ordinary life, car enthusiasts troubleshoot fuse problems in the simplest old-fashioned way: they install a so-called bug. But here you should use your mind and take into account that one day this pseudo-device will not work, and a fire may occur. If some parts of the car have failed, then there is no need to rush to the store to buy new ones.
Often the reason is only a short circuit, and you need to check the car fuses. Modern cars usually have two of these units. One of them is located in the cabin, and the second is in the engine. The interior unit can most often be found behind the steering column panel, where the luggage compartment is, or under the seat. There is a marking on the back of the block body that indicates the name of the devices or icons corresponding to each of them.
Once a failed section has been found, it is not difficult to find the burned one among all. Then you need to make sure that it actually burns. Visual inspection will not give anything. It happens that the jumper remains intact, but the fuse itself does not work. This can happen due to oxidation of the metal on the element. There is a more accurate verification method. To do this, you don’t have to remove the element from the socket. First you need to turn on what stopped working: headlight, horn, lift, etc.
You should then check to see if there is voltage at the specific fuse. If there is no voltage on at least one of the terminals, the fuse has blown and needs to be replaced. Step-by-step replacement instructions:
It is worth noting that it is not so easy to go to the store and buy a quality product that will not burn out in a few hours and will not cause a fire. Before you pay money for a purchase, you must carefully examine the appearance of the product. If you have doubts about the quality of your purchase, you should test it before installation.
The test order is as follows:
- Buy a spare just in case.
- Connect the wires to the metal ends of the device, one to the plus, the other to the minus.
- If you get a good fuse, it will burn out immediately, a low-quality fuse will only melt and cannot be installed.
Now you can proceed to the most important stage - replacement. To do this, you need to put a new one in place of the burnt one, but There are some points to pay attention to:
After everything is finished, you need to check again all the operating electrical components in the car. The replacement will be successful if no more problems arise in the operation of the machine.
Algorithm for working with a microwave oven
Most modern microwaves do not have high-voltage fuses, so the mains protector takes over the responsibility. But it burns out only if the transformer receives double load. In case of breakdown you need to do the following:
For those users who are new to the oven, additional recommendations are needed. To remove the top cover without any problems, you first need to find all the fasteners and carefully remove them from their sockets. During a visual inspection, you can use a magnifying glass to accurately determine the presence of a thread, and also clearly see the markings on all elements. A new fuse must be purchased with a blown one, so that they are identical, otherwise the thread may burn out immediately after switching on.
Primary interest in the topic arose due to the lack of commercially available 200 mA fuses, the same ones used by the manufacturer in the Mastesn multimeter. I tried setting it to 160 mA, but nothing good came of this idea - they “burn” almost after every measurement. I set it to 250 mA (no incidents so far). And since I go towards achieving my goal with a bit of passion, and besides, I’m no stranger to finding a way out of difficult situations “at random,” it’s not so rare to have to change burnt fuses. My next voyage to places selling electronic components, this time regarding 0.5 and 1 ampere fuses, was again disappointing. Fortunately, radio amateurs don’t have the habit of throwing anything away (they can only pick it up and get it in any available way), so a certain number of blown fuses have already accumulated.
Repairing a fuse or, as they used to say in the old days, “installing a bug,” as I initially imagined, is not at all a tricky matter. There are plenty of instructions on this matter on the Internet. All it takes is finding wires of suitable thickness, and the rest is a matter of technique.
True, there was no information on where to find the necessary wires with a diameter of 3 microns (0.03 mm).
However, we were lucky, and a wire with a diameter of 0.03 mm was found in the coil of the frame of the measuring head that could not be restored. From where it was taken using a powerful watch magnifying glass, acetone and a certain amount of patience.
A wire with a diameter of 0.05 mm was found on the board of the Slava electronic-mechanical alarm clock. There were no more problems here, you just had to dip it in acetone, and the wire from the reel began to unwind on its own. After communicating with a wire with a diameter of 0.03 mm, this one was already like a “rope”.
The next step was opening the fuses. This became possible only after heating the metal caps with a soldering iron. Now, wise from practical experience, I know that you only need to shoot one of them. The next step in the end part of the caps, using a well-heated soldering iron with a thin tip, was to remove the tin from the holes through which the wire that functions as a fuse is passed directly.
First repair operation. A wire of the required diameter equal to twice the length of the fuse being repaired is passed through the hole in the first cap, the glass body and sealed. With the obligatory preliminary removal of varnish insulation from the edge (if it remains after acetone).
The second step is to place the cap on the glass body using glue (the most convenient brand is BF-6).
The final operation is to pass the wire into the hole of the second cap and also solder with subsequent gluing. Immediately after soldering, you need to check the fuse with a multimeter.
After trimming the ends of the fuse wires protruding from the outside, you can lay out the ready-to-use products in even rows, but so that they do not get mixed up in any case, and admire the creation of your hands. I was especially pleased that we managed to repair miniature specimens. Sometimes these are really needed.
And the last step - the previous markings were removed from the metal caps, now serviceable fuses, using a file (now I know that it is much more convenient to do this at the very beginning of the repair). Everything is packaged in bags and ready to use.
Epilogue: in case of emergency, repairing fuses is possible, even with a nominal value of 0.5 A. A micrometer is required.
Using a similar strategy, you can repair car fuses (fuse links) and many others. I imitated the Tula "Lefty" Babay.
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