Detailed explanation of circuit fault types and causes
Source: Date:2022-04-22 16:31:06
We all know that circuit failure is a physical phenomenon. Then, do you know the types of circuit faults? What is the cause of the fault? Next, please follow Xiaobian to have a look!
There are two types of circuit fault, short circuit and open circuit.
Short circuit is divided into power short circuit and electrical short circuit.
1. The power supply is short circuited, and the guide wire is directly connected to the two poles of the power supply without passing through the electric appliance. This will cause excessive current in the circuit and burn out the power supply. This is not allowed.
The power supply is short circuited, as shown in the figure. One is that the switch is closed and the wire is directly connected to the two poles of the power supply; The other is that the switch is closed and the ammeter is directly connected to the two poles of the power supply.
2. Short circuit of consumers means that one or more (of course not all) of the series connected consumers do not work in the circuit, which is caused by wiring or circuit failure. Generally, this situation will not cause great damage.
Cause analysis:
(1) Leakage: the line insulation is damaged or aging, and the current leaks out from the insulation structure. This part of leakage current does not form a loop through the original circuit, but forms a loop through the building and the earth or forms a local loop between the phase line and the neutral line. If the leakage is not serious, there is no obvious fault phenomenon; When it is serious, there will be such fault phenomena as building electrification and unreasonable increase of electricity. The causes of leakage can be summarized as follows: ① during construction, the insulation structures of wires and lighting accessories were damaged. ② The wiring and lighting accessories are out of repair for a long time and the insulation is aging. ③ Illegal installation, for example, the conductor is directly buried in the paint layer of the building.
(2) Overload: the actual electric quantity exceeds the rated capacity of the line conductor. The fault phenomenon is: the protection fuse is burnt out and the temperature of the overload device rises sharply. If the protective device fails to play a protective role in time, it will cause serious electrical accidents. The main causes of overload fault are as follows: ① the conductor section is small, the original design line is not matched with the actual application, or it is caused by blind excessive power consumption. ② If the power supply voltage is too low, the electric fans, washing machines, refrigerators and other equipment whose output power cannot be reduced correspondingly will increase the current to make up for the shortage of voltage, thus causing overload.
(3) Short circuit: many electrical fires are caused by short circuit. There are many reasons for short-circuit, mainly including: ① poor construction quality and failure to process according to the requirements of standardization. ② It is caused by short-circuit fault inside the electric appliance. ③ The line is in disrepair for a long time. ④ Lead or accessories are damaged by external force.
