What is an air circuit breaker?
Device
When the load is disconnected, powerful consumers, an arc arises between the diverging contacts for disconnection, the strength is not inferior to the rated current. During this phenomenon, plasma is formed, the temperature rises, as a result of which an uncontrolled self-sustaining arc can form, which can melt the switch contacts and even spread to the neighboring phase, causing a phase short circuit, which can result in the failure of expensive equipment. To avoid this phenomenon, a device was developed - an extinguishing chamber.
The design of the air circuit breaker is clearly illustrated in the diagram below (click on the image to enlarge):
Operating principle
At the moment of breaking contacts arcs occur. Reaching the lattice of the extinguishing chamber, it begins to stretch, and under the influence of heat, the air in the chamber flows out through the lattices, dragging the products formed by the plasma further behind, stopping its manifestations physically.
Understanding the processes occurring in switched circuits, as well as methods for suppressing undesirable phenomena, helped to create devices that are quite compact in size and weight, capable of shutting down the current in hundreds of amperes. The photo below shows a typical representative of a circuit breaker:
Scope and purpose
Aerial machines are used for industrial needs, in the energy sector, in the private sector. To date, protective devices of various sizes and sizes have been developed. From residential circuit breakers to withdrawable type protective switching equipment with an integrated parameter controller.
Now let's talk about what machines of this type are used for. The main purpose of air circuit breakers is to protect electrical equipment and power lines from short circuit currents, as well as from excessive power consumption by controlling the amount of current passing through the contacts of the machine.
Requirements for modern air circuit breakers:
- unlimited time of passage of rated current;
- repeated shutdown of short circuit currents;
- short response time;
- resistance to repeated thermodynamic loads;
- the presence of internal protective mechanisms;
- selectivity.
Due to the relative simplicity of the design, they firmly took their place under the sun and also continue to improve in technical terms.
Finally, we recommend that you watch the video, which clearly shows what the air machine consists of:
So we examined the purpose, principle of operation and the design of an automatic air circuit breaker. We hope the information provided was useful and interesting for you!
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