A Comprehensive Guide of Air Circuit Breaker

Among various devices for circuit protection, air circuit breaker (ACB) and miniature circuit breaker (MCB) are the two most common. This comprehensive guide will delve into how these two devices work, their applications, and how they can help you protect your circuits and ensure the safety and stability of the electrical system.

What is air circuit breaker

Air circuit breaker uses air as the extinguishing medium to break the circuit. It is designed to handle high-voltage, high-current environments and is commonly found in industrial distribution systems, substations and large commercial buildings. Compared with other types of circuit breakers, air circuit breaker has higher breaking capacity and better resistance to overload current, which can quickly and reliably cut off the circuit under extreme conditions and effectively prevent the occurrence of fire accidents.

Working principle and structure

The working principle of air circuit breaker is based on electromagnetic and thermal effects. When there is a short circuit or overload in the circuit, the electromagnetic coil will generate enough magnetic force to push the mechanical mechanism and drive the operating mechanism to separate the contact.

During this separation process, the thermal effect element will also heat when the current is overloaded, resulting in the bending of the bimetal sheet, and the incoming arc is generated in the air gap and is rapidly cooled and stretched, and finally extinguished, so as to cut off the fault current. This process is completed in almost milliseconds, ensuring efficient protection and quick recovery of the power system.

Air circuit breaker (ACB) is a complex electrical device whose structure is designed to ensure efficient and reliable circuit protection. The following are the main components of air circuit breaker.

Functions and characteristics

According to different functions and designs, air circuit breaker can be divided into three types.

With its efficient and reliable design, air circuit breaker has several significant advantages.

First of all, air circuit breaker is equipped with high score breaking ability, which makes it suitable for high voltage, high current occasions, and can effectively deal with short circuit faults.

Secondly, due to the use of high-quality materials and advanced technology, long-term stable operation is guaranteed.

Then, the maintenance of the air circuit breaker is simple thanks to its structure and is easy to check and update.

Finally, artificial intelligence has gradually entered the air circuit breaker design. Modern air circuit breaker is usually equipped with electronic trips, which can perform remote monitoring and fault warning, and improve management efficiency.

What is miniature circuit breaker

If air circuit breaker is the giant in the field of power safety, then miniature circuit breaker is the meticulous guardian. Designed for low-voltage distribution systems, miniature circuit breaker is widely used in homes, offices and small shops, which is ideal for protecting short circuits, overloads and ground faults.

Working principles and structure

The working principle of miniature circuit breaker is based on the electromagnetic and the thermal effect, and the protecting function is realized through the internal thermal magnetic release. When the current exceeds the rated value, the heat element heats up and bends, pushing the trip mechanism to act; When the short circuit current is encountered, the electromagnet quickly draws, and the trip is also triggered to realize the rapid disconnection of the circuit.

First of all, electromagnetic effects are mainly used for short circuit protection. When a short circuit occurs, the current will increase sharply. The electromagnetic coil inside the breaker then generates a powerful magnetic force, pushing the mechanical mechanism to act quickly and disconnect the circuit. The response time is very short, usually within a few milliseconds, which can effectively prevent short-circuit current damage to electrical equipment.

Secondly, when the current in the circuit continues to exceed the rated value (such as overload), the bimetal sheet inside the circuit breaker will bend due to heat. The bending of the bimetal will trigger the mechanical mechanism and disconnect the circuit. The response time of the thermal effect is relatively slow, which is suitable for the case of long-term overload and can effectively prevent the equipment from overheating and damage.

Thirdly, miniature circuit breaker is usually equipped with a hand-operated handle through which the user can manually disconnect or switch on the circuit. After troubleshooting, the manual handle can reset the circuit breaker and restore power to the circuit.

Functions and characteristics

According to different functions, miniature circuit breaker can be divided into main two categories.

1. Classification by number of poles

2. Classify by trip characteristics

With its unique design, miniature circuit breaker has many characteristics and advantages.

First of all, miniature circuit breaker is small and flexible, easy to install in a compact distribution box, saving space.

Secondly, it can provide diversified protection, such as overload, short circuit and leakage protection to meet the needs of different scenarios.

Then, due to the handle design, it has higher security. When the human body is electrocuted, it can quickly cut off the power supply and effectively prevent electric shock accidents.

Of course, it is also more economical with moderate price, suitable for large-scale popularization.

Comparison of air circuit breaker and miniature circuit breaker

Air circuit breaker (ACB) and miniature circuit breakers (MCB) are both electrical devices used for circuit protection, but they differ significantly in design, application, and performance.

For design and structure, air circuit breaker is larger in volume and more complex in structure, suitable for high current applications. At the same time, it uses air medium and has strong extinguishing ability.

While miniature circuit breaker is compact in size and simple in structure, suitable for low current applications. It uses air or small arc extinguishing chamber, and the arc extinguishing ability is relatively weak.

For actual application, air circuit breaker is suitable for main distribution systems in industrial, commercial and large residential projects, high current circuits (usually 630A to 6300A). Suitable for protecting large motors, transformers and main switchboards.

But miniature circuit breaker is more commonly used in branch circuits, low current circuits (usually 6A to 125A) in homes, offices and small business locations. Suitable for protecting lighting, sockets and small electrical equipment.

For installation and maintenance, the installation of air circuit breaker is complex and requires professional and technical personnel to operate. Moreover, regular maintenance of this type of equipment is required to check contacts, interrupters and operating mechanisms.

While the installation of miniature circuit breaker is simpler and can be completed by ordinary users. Maintenance requirements are low, usually only needed to check regularly whether the operation is normal.

Air circuit breaker vs miniature circuit breaker: how to choose the right one?

Choosing between air circuit breaker and miniature circuit breaker depends on several factors, including the application, electrical load, and specific requirements of your electrical system.

As the previous sections have illustrated from their working principle to application, in short, air circuit breaker (ACB) is suitable for high current (above 630A), industrial and large commercial scenarios, providing comprehensive overload, short circuit and ground fault protection, but large size, high cost and complex installation; Miniature circuit breaker (MCB) is suitable for low current (under 125A), home and small business applications, provide basic overload and short circuit protection, and are small, low cost and easy to install. Just select an appropriate circuit breaker based on current requirements, applications, and budgets.

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The End

Air circuit breaker and miniature circuit breaker all provide reliable protection for a variety of circuits through different designs and applications. Hopefully, through this comprehensive guide, you can get a better understanding of the two types of circuit breakers and choose the most suitable one for your own electrical system