What Is An Air Circuit Breaker And How It Works?

The modern power system is beginning to make more use of air circuit breakers that can protect power systems and electrical equipment from possible risks of faults and provide stable power supplies in various situations. This article will introduce in detail the concept, operating principle, characteristics, applications, and future trend of air circuit breakers.

What is an air circuit breaker?

Air circuit breaker is one of the most crucial switching devices protecting power systems and electrical equipment. In case of an overload, short circuit, or ground fault, it can rapidly cut off the circuit to prevent the damage of equipment or fire risk. Its core characteristic is that air is used as an arc-extinguishing medium for rapidly disconnecting the circuit to interrupt fault current.

Working Principle of Air Circuit Breakers

The working principle of air circuit breakers is based on arc extinguishing technology. When a short circuit or overload fault occurs in the circuit, the contacts in the circuit breaker quickly separate and generate an arc. Air circuit breakers extinguish arcs through the following steps:

Contact separation: When a fault occurs, the contacts separate to generate an arc.

Arc stretching: Use arc guide plates with special shapes to stretch the arc, so as to increase the length of the arc.

Cooling and extinguishing: Reduce the temperature of the arc through air and thus cut off the current.

This design makes the circuit breaker capable of cutting off the circuit in a very short period of time and reduces the impact of the fault on the power system.

Main features of air circuit breakers

High reliability

Air circuit breakers have compact structures and stable performance, which allows them to work for a long period in complicated power conditions.

Multifunctional protection

It provides a range of functions, including overload protection, short circuit protection, earth fault protection, and undervoltage protection, among others, that effectively improve the safety of the power system.

Fast Arc Extinguishing

It has been designed to use air as the arc extinguishing medium so that under high current, the arc is extinguished rapidly to reduce the effect on equipment and systems.

Visual operation and monitoring

Most air circuit breakers have status display panels and intelligent monitoring functions to observe circuit operation in real-time.

Primary application of air circuit breaker

The main applications of an air circuit breaker are within low-voltage and medium-voltage power distribution systems in:

Power plants and substations: These are applied in key equipment for protection and ensure stability within the grid.

Industrial manufacturing: Offer safety protection against heavy load on the equipment to avoid damages due to any kind of failure.

Commercial buildings: Building power distribution system protection against overload and short circuits, which lead to fire breakouts.

Data center: For the continuity of the key equipment operational and also avoid data losses caused by a power outage.

Classification of air circuit breakers

According to the purpose and technical characteristics, air circuit breakers can be divided into the following types:

Frame air circuit breaker (ACB)

Normally used in low voltage power distribution system with high rated current.

Molded case air circuit breaker (MCCB)

The shell is made of plastic material and suitable for protection of small and medium currents.

Intelligent air circuit breaker

Equipped with intelligent module, it realizes the function of parameter setting, real-time monitoring and fault diagnosis.

Key factors in selection of air circuit breakers

In the selection of an air circuit breaker, rated current, breaking capacity, and installation method shall be selected based on actual needs.

Rated current: The selected circuit breaker should be able to bear the normal operating current.

Breaking capacity: The selected model should meet the requirements of short-circuit current breaking.

Installation method: Fixed or drawer-type circuit breakers shall be selected according to the distribution cabinet or on-site requirements.

Intelligent requirements: If remote monitoring and control are needed, models with intelligent functions can be chosen.

Maintenance and maintenance of air circuit breaker

For long-term and stable operation, air circuit breakers require regular maintenance. Here are some common suggestions for maintenance:

Keep the outside and inside of the circuit breaker box clean to avoid erosion on performance because of dust accumulation.

Check the wear at contact points and change the contacts, if needed.

Test the protection function to make overload and short-circuit protection mechanisms work normally.

Check the installation environment to avoid getting wet and exposing the circuit breaker to corrosive gases.

Future trends

With the development of smart grids and Industry 4.0, air circuit breakers are developing towards intelligence, modularity and high performance. Intelligent air circuit breakers equipped with IoT functions can achieve remote monitoring, fault warning and energy efficiency management, providing safer and more efficient solutions for modern power systems.

Summary

Air circuit breakers are important equipment to ensure the safety of power systems, with advantages such as multi-function protection, fast arc extinguishing and intelligent control. Whether in industrial, commercial or residential areas, the correct selection and proper maintenance of air circuit breakers are the key to ensuring the safe and stable operation of power systems. If you are looking for high-performance air circuit breakers, it is recommended to choose a reliable manufacturer to ensure product quality and technical support.