Protection against overload currents. Scheme, description

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Electrician

Protection against overload currents. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / Electrician's Handbook

Protective devices shall cut off any overload current flowing through the conductors before such a current could cause a rise in the temperature of the conductors that is dangerous to the insulation, connections, terminals or the environment surrounding the conductors.

GOST 50571.5-94 imposes the following requirements on protective devices.

The performance of any protective device that protects the cable from overload must meet the conditions:

Where

- operating current of the circuit; - admissible continuous cable current; - rated current of the protection device (for a protection device with adjustable characteristics, the rated current is the current of the selected installation); - the current that ensures reliable operation of the protection device, in practice it is taken equal to: the operation current at a given operation time for circuit breakers; melting current of the fuse-link at a given operating time for fuses.

Note. In certain cases, in order to avoid unintended operation of the protection, it is necessary to take into account the peak values of the load currents. In the case of cyclic loading, the values и choose based on values и for a thermally equivalent constant load.

Publication: electro.narod.ru

See other articles Section Electrician's Handbook.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Traffic noise delays the growth of chicks 06.05.2024

The sounds that surround us in modern cities are becoming increasingly piercing. However, few people think about how this noise affects the animal world, especially such delicate creatures as chicks that have not yet hatched from their eggs. Recent research is shedding light on this issue, indicating serious consequences for their development and survival. Scientists have found that exposure of zebra diamondback chicks to traffic noise can cause serious disruption to their development. Experiments have shown that noise pollution can significantly delay their hatching, and those chicks that do emerge face a number of health-promoting problems. The researchers also found that the negative effects of noise pollution extend into the adult birds. Reduced chances of reproduction and decreased fertility indicate the long-term effects that traffic noise has on wildlife. The study results highlight the need ... >>

Wireless speaker Samsung Music Frame HW-LS60D 06.05.2024

In the world of modern audio technology, manufacturers strive not only for impeccable sound quality, but also for combining functionality with aesthetics. One of the latest innovative steps in this direction is the new Samsung Music Frame HW-LS60D wireless speaker system, presented at the 2024 World of Samsung event. The Samsung HW-LS60D is more than just a speaker system, it's the art of frame-style sound. The combination of a 6-speaker system with Dolby Atmos support and a stylish photo frame design makes this product the perfect addition to any interior. The new Samsung Music Frame features advanced technologies including Adaptive Audio that delivers clear dialogue at any volume level, and automatic room optimization for rich audio reproduction. With support for Spotify, Tidal Hi-Fi and Bluetooth 5.2 connections, as well as smart assistant integration, this speaker is ready to satisfy your ... >>

A New Way to Control and Manipulate Optical Signals 05.05.2024

The modern world of science and technology is developing rapidly, and every day new methods and technologies appear that open up new prospects for us in various fields. One such innovation is the development by German scientists of a new way to control optical signals, which could lead to significant progress in the field of photonics. Recent research has allowed German scientists to create a tunable waveplate inside a fused silica waveguide. This method, based on the use of a liquid crystal layer, allows one to effectively change the polarization of light passing through a waveguide. This technological breakthrough opens up new prospects for the development of compact and efficient photonic devices capable of processing large volumes of data. The electro-optical control of polarization provided by the new method could provide the basis for a new class of integrated photonic devices. This opens up great opportunities for ... >>

Random news from the Archive

Healing session of an earthquake 13.11.2003

Many of the survivors of the catastrophic earthquake in 1999 in Turkey (7,4 on the Richter scale, thousands of deaths) still cannot come to their senses: they developed the so-called post-traumatic syndrome.

The victims do not find a place for themselves, do not sleep well, are afraid to stay indoors, and women who survived the earthquake are three times more likely than men to develop this nervous breakdown. Without treatment, only 10 percent of patients recover from such fears.

Turkish physician Metin Basoglu used a powerful geophysical installation - an earthquake simulator to treat post-traumatic syndrome. The platform, on which anti-seismic structures of buildings and machines are usually tested for strength, vibrates with a given amplitude.

An hour stay on such a simulator, as it turned out, cures 80-90 percent of patients, provided that they themselves hold a remote control with which they can regulate the duration and strength of the shocks.

Other interesting news:

▪ instant ice cream

▪ Cosmetics 2000 years old

▪ The Arctic is waiting for new records of melting

▪ Series of ceramic diodes CeraDiode

▪ Mini ion thruster tested in orbit

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Metal detectors. Article selection

▪ article All this jazz. Popular expression

▪ article Since when have handkerchiefs been used? Detailed answer

▪ article Mini bearing puller. home workshop

▪ article Five-band vertical antenna. Encyclopedia of radio electronics and electrical engineering

▪ article Guessing stacks of cards. Focus Secret

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews