Views:235 Author:Site Editor Publish Time: 2020-12-03 Origin:Site
Electrical circuit failure, such as the short circuit in power system, has always been a problem that plagues a safe power supply. Failure accidents account for almost 2/3 or more of line loss and cost. Therefore, seeking more effective line fault prevention measures and maintenance methods has always been the concern of electric power workers.
The wires that connect electrical equipment and transmit electrical energy can be called electrical lines, ranging from high-voltage overhead power lines to small-to-light current control.
(1) Insulation damage; (2) Poor contact; (3) Severe overload; (4) Wire break; (5) Insufficient spacing and poor protection; (6) Live protection of the conductor, etc.; (7) Power supply voltage, frequency, three-phase imbalance; (8) heating of the equipment; (9) poor surrounding environment; (10) insulation breakdown of insulating materials.
Because there is an electrical short circuit, the resistance value of the circuit is very small or close to zero, so use a multimeter to measure the resistance value at both ends of the circuit. In order to measure more accurately, it is best to set the resistance gear to a low gear. When the reading is small or zero, the line must be short-circuited. When inspecting the line fault, it is found that the electrical line has large-capacity capacitor equipment, and the capacitor needs to be thrown off for measurement. If the electrical circuit is in an electric wire short circuit in parallel, check the branches one by one until the short-circuit branch is detected. Sometimes the electrical circuit seems to be broken and not broken. It is better to use a shaking meter to measure it. If there is a cable short circuit, it will prevent it from being zero. But it is best to check whether the insurance is damaged first to avoid wasting time.
Electrical circuit breaks include loose connections, excessive short-circuit current burns, fuse burns, and some electrical component faults, such as defective switch contacts, such as contactors, relays, rotary switches, reset switches, etc.
Electric circuit faults can be checked with or without power. Check with power is to measure whether there is the voltage at both ends of electrical components. Because the circuit is disconnected, there must be no current in the circuit, and it is impossible to produce a voltage drop in each electrical component. Use a multimeter to measure the voltage at both ends of each component or wiring in the circuit, indicating that there is an open circuit in the section where the test leads are overlapped. Sometimes the light bulb can be checked to find out the position of the open circuit. The power-off inspection is to check whether the resistance is infinite. The measurement is to find that the resistance value of the test pen section is infinite, and there must be a break point, and gradually reduce it until the break point is determined. When encountering some electrical components, such as contactors, relays, and various switches, manually operate to determine whether there is a false open circuit, so as to avoid unnecessary maintenance.
Finding a short in a circuit or other electric faults, you can try the fault circuit indicator. According to different situations, there are earth fault indicator testers, fault passage indicators for overhead lines, earth leakage indicators, etc.