A fuse is what? Principle of operation of fuses

Electronics in the car is responsible for many systems and subsystems. Lighting, audio, cooling, yes there, you do not even run the engine if the electricity goes out. Unfortunately, many drivers "swim" in this area and are not always able to cope with electrical circuit failures, despite the fact that often problems are associated only with a burnt-out fuse. This is a protective mechanism, which often comes into disrepair and disorients the drivers. In the following material, we will discuss in more detail what the fuse is, how it works, and how to make a replacement in the event of failure of one of them.

What is a fuse?

A fuse is a special switching electrical device whose task is to disconnect the protected circuit by opening it or destroying (burning) pre-arranged conductive parts when an excessively high current flows through them. Roughly speaking, a fuse is a protective mechanism that self-destructs in the event of a threat to all electronics (in a car or electric appliances). A kind of self-sacrifice, if you think metaphorically.

How does the fuse work?

In cars fuses are used and are selected in accordance with the nominal permissible load. In the event of an emergency, when the voltage rises, the fuse link of the fuse breaks down and opens the electrical circuit.

The process of self-destruction starts if:

• Short circuit - occurs if the insulation of conductive parts or incorrect connection of devices has been broken. The problem of frayed insulation cables in the car is generally one of the most frequent causes of fuse blowouts.
• Incompatibilities of the power of the consumer device and the nominal amperage allowed for a particular electrical circuit. This problem is faced by those who decided to install in their car additional electrical equipment (lighting, radio and others like them). Such powerful energy consumers are powered by basic wiring that is not designed for such a high current value. Due to excess current capacity, the wires are fused and lead to a short circuit, which leads the fuses out of order.

Threshold of fuses

From the above, it becomes clear that the fuse in the car is destroyed in case of exceeding the nominal value of electricity. The fuse part of the fuse overheats and burns.

The rated current of the fuse is calculated by the formula: Inom = Pmax / U.

• Inom is the nominal current that is measured in Amps;
• Pmax is the maximum possible load that a given device can handle. The power is indicated on the instruments and is measured in watts;
• U is the voltage level of the network. This indicator is measured in Volts. The voltage level in the vehicle network is 12 Volts.

Fuse types

Fuses are categorized according to the rated power, as well as the size of the fuses themselves.

By size, the fuses are divided into:

• Micro - the most compact.
• Mini - a little more (16 millimeters).
• The norm is the usual size (19 millimeters).
• Maxi is the largest (34 millimeters).

What is more important is the separation according to the strength of the current. For convenience, they are all marked with certain colors, but it is not worth focusing on the color, because in the VAZ cars fuses are marked with colors different from those in foreign cars, because there are no standards in this area.

Fuse Location

The first thing that a motorist will have to face when trying to check the condition of the fuses or replace them is the search for a safety block. The thing is, to find out where the fuse is located, the task is not trivial. In different models of cars, the fuse box is located in different parts of the cabin or even under the hood. Sometimes the number of fuses greatly increases, and the car manufacturer puts several blocks in different parts of the machine. Because of this disorder, it is simply impossible to suggest a universal scheme or instruction for finding a safety block. For example, in the domestic production of fuses are under the hood (the classic version of the location for the "Lada"). In foreign cars the situation is more complicated. The fuses in the Toyota Corolla are located to the right of the steering wheel on the dashboard. It would seem that the producers of one country should be similar in choosing the location of the elements, but in reality everything is different. The fuses in the Nissan Almera are located to the left of the steering wheel, in a small pocket.

Fuse test

A working fuse is first and foremost safety. Therefore, it is necessary to maintain them in working order. If any element of electronics in the car has failed, it is necessary to check up working capacity of a detail. How can this be done? Many drivers simply gain access to the safety block and take out the fuses in turn to visually assess their condition. Owners of cars simply look, whether the jumper in the fuse is damaged. Of course, this method works, but it is typical for dilettantes, and besides, it is not always reliable, because the jumper can remain whole even if the fuse burned out. To check the condition of the parts, it is better to include the circuit that stopped functioning (this could be any electronics, be it lights, a stove or a stereo system), and then use a multimeter to check the voltage level in the fuse responsible for this circuit. Such a test will take much less time and give an accurate result.

Replacing the fuses

If the fuse fails, it must be replaced immediately. First we find the fuse box (if the unit is located under the hood, the battery should be disconnected in advance). Remove bolts from the cover of the safety block. Use a 10-wrench to unscrew the nut, which holds the clamp with the wires. This is done in order to move them (they close access to the fuses). Also, for greater comfort, you can dismantle the panel with fuses, but this is not necessary. Then we simply remove the non-working fuse and put in its place a new (of course, suitable in size and at face value).

Selecting and testing the fuse

Choosing which fuse you need, you need to keep in mind a number of conditions. When choosing a new part, it is necessary to apply only to the proven manufacturers, responsible for the quality of their products. It is advisable to consult with other motorists who have an identical auto and load on the electrical circuit. This is very important, as most fuses are made in China, where nobody controls this process. Because of poor-quality products, you can not only destroy electronics, but the entire car. There have been cases when a block with fuses burned, but the fuses themselves remained intact.

To check the quality of the part, it is necessary to provoke a short circuit outside the car, and if the fuse burns out, it means it's quality and you can take the whole lot to replace the damaged ones in your car.

To create an artificial short circuit, it is necessary to fasten to the ends of the fuse on the wire, and then one of them must be connected to the plus, and the second to the minus and put on them an electric current with a voltage higher than the nominal one.

Installation of additional equipment

If you plan to install additional equipment into the car, it is necessary to find out whether the normal wiring of your car will withstand such a load. If not, for new equipment it will be necessary to conduct separate wiring, and the rated current of the fuse for it must be one and a half times higher than the rated current in the circuit. To calculate the load, you can use Ohm's law and special tables.