Tripped again! Who is protecting the circuit at home?

Speaking of tripping, we all know that when the total power of household appliances is too large, a large current will be generated in the circuit, which will cause the circuit to automatically trip.

Sometimes, even though the power of the electrical appliances is not large, the current will be too large. Why?

　　This situation(2021 hermes bags) is often due to errors in the circuit modification, damage or aging of the wire insulation, which directly connects the live wire and the neutral wire, resulting in a short circuit. A short circuit in a household circuit can cause power outages and burnout of electrical equipment, or cause electric shock, fire and other disasters, which is very dangerous.

　　If the current is too high, it will trip, so what is the principle of the trip? And who is taking on the role of defender of the safe operation of home circuits? All this has to

The incoming wire is the wire connecting the outdoor power supply circuit. There are generally two wires, which are what we usually call the "live wire" and the "zero wire". The voltage between the two is 220V, and the voltage between the live wire and the ground wire is 220V. The voltage between the neutral wire and the ground wire is 0V. Therefore, it is safe to touch the ground wire or the neutral wire under normal conditions, while touching the live wire will cause electric shock. Of course, if the neutral wire is poorly grounded, it is very easy to get an electric shock, so we try not to touch any wires.

Meter

　　The electric energy meter is generally installed on the main road of the home circuit. With the electric energy meter, the power consumption in the circuit can be accurately measured, which is also the main basis for the power supply department to calculate the electricity bill. Commonly used household electric energy meters are mainly electronic and inductive.

Socket

　　 Sockets need to be connected in parallel in the circuit to energize various mobile appliances such as refrigerators, TVs, washing machines, air conditioners, etc. Generally speaking, there are two sockets and three sockets.

　　 switch

　　 The switch device is connected in series on the main trunk road, which can control the on-off of the entire family circuit. It can not only facilitate the detection of circuit replacement equipment, but also cut off the circuit in the event of a short circuit or overload. It is the commander of the entire circuit operation.

　　Safety device

　　The safety device is also connected in series on the main road, which can automatically cut off the circuit before the current increases to a dangerous degree. Both are the protectors of home circuits and are important core components of home circuits.

　　How does the safety device protect the circuit?

As we mentioned earlier(sitemap), if the total power of electrical appliances is too large, or the circuit is short-circuited, it will cause excessive current in the circuit and generate too much heat, which will cause a fire. Therefore, in order to prevent danger from excessive current, it must be installed in the circuit Switch devices and safety devices, fuse or air switch are often used in home circuits.

　　 The fuse is called the "guardian of safe electricity use" and was invented in 1880 by the well-known "father of electricity" Thomas Edison (Thomas Edison). At that time, incandescent lamps were expensive, so fuses were originally used to protect expensive incandescent lamps.

Fuses are generally made of lead-antimony alloys with higher resistivity and lower melting points. We have learned in the physics class of junior high school that when the current in the circuit is too large, the heat generated will increase the temperature to the melting point of the fuse, and the fuse will blow and automatically cut off the circuit, thus playing a protective role.

　　The commonly used fuses include chip fuses, alarm fuses, miniature fuses, tube fuses, and so on.

The core of the function of the air switch is the tripping mechanism. The tripping mechanism is a set of connecting rod devices. When a fault occurs in the circuit and an excessive current is generated, the electromagnetic tripping device will generate enough suction force to attract and hit the armature. The lever causes the hook to rotate upwards around the shaft seat to release the lock. The lock breaks the three main contacts under the action of the reaction spring, thereby completely disconnecting the circuit.

　　 Different from the high-temperature fuse of the fuse, the working principle of the air switch is a series of interlocking electromagnetic chain reactions. After the fault in the circuit is eliminated, the switch can be turned on again. This reusability is also its biggest advantage compared with the fuse.

　　 But on the other hand, because the air switch has a certain thermal hysteresis, the action of the air switch has a certain delay at the moment when a large current passes, and it cannot be opened immediately, but the fuse can be blown immediately. In this case, the advantages of the fuse appear, so in some occasions, the fuse is still used as an important protection element in the circuit.

　　 In short, after installing a fuse or an air switch, the operation and use of the home circuit can be reliably guaranteed.

Of course, although the fuse and air switch have always adhered to the attitude of "sacrifice one, protect thousands of families", jump in danger and perform their duties, I still hope that everyone can also master some basic common sense of safe electricity use in peacetime, and develop Good electricity usage habits, try to avoid various safety hazards~