Advantages of Air Circuit Breakers
Air circuit breakers is one of the oldest, simplest and most widely used circuit breaker in the field of low voltage. The advantages are significant and can be understood in the following ways:
I. Extremely High Safety-this is its biggest advantage
Air circuit breakers use air as an arc extinguishing and insulating medium and have no oil, gas or vacuum bulbs. What does this mean?
There is absolutely no risk of fire or explosion. Oil circuit breakers use transformer oil to extinguish the arc, and in the event of an internal failure, oil may splash or even explode. SF6 circuit breakers are not flammable, but there is a risk of suffocation if SF6 gas leaks. However, air circuit breakers depend entirely on air; even if the contact or arc fencing burns, there will be no fire, explosion or toxic gas.
Therefore, air air circuit breakers preferred in locations where safety requirements are extremely high,such as data centers, hospitals, shopping malls, residences, etc.
ii. The structure is simple and High Reliability compared to other types of air circuit breaker. The internal structure of an air circuit breakers is very simple: a bimetallic strip (thermal trip), electromagnetic coil (electromagnetic stroke) and arc gatearc) --the three main components. There are no ageing vacuum bulb, no SF6 gas tests and no oil replacements.
The simpler the structure, the fewer potential points of failure and the higher the reliability. Air-circuit breakers typically have a mechanical lifespan of tens of thousands of people and an electrical lifespan of thousands, making them extremely durable compared to similar products.
III. Lowest Cost-King of Cost-Effectiveness in low-pressure areas, which is a huge advantage:
Cheap to procurement cost: air circuit breaker (MCB) can cost only a few to a few dozen yuan, factory-molded case circuit breaker (MCCB) can cost hundreds to thousands of yuan, and large frame air circuit breaker (ACB) can cost thousands to tens of thousands of yuan. By comparison, vacuum circuit breaker with the same parameters cost 30 to 50 per cent more and an SF6 circuit breaker cost several or even 10 times more.
Running costs are virtually nil: there is no need to replace vacuum bulbs, replenish SF6 gas or change oil. After a fault, simply reset the circuit breaker to continue working, and the fuse requires to be replaced after it has blown. Daily maintenance involves only dusting and tightening screws at little cost.
Low installation costs: simple structure, easy wiring, no complex auxiliary systems (e.g. gas monitoring system for SF6 circuit breakers, air compressor system for compressed air circuit breakers).
IV. INTRODUCTION Strong breaking ability, suitable for largecurrent condition.
In low-voltage applications (380V/690V), air circuit breakers have a crushing capacity of 10kA to 100kA or higher, making them ideal for low-voltage applications. In particular, racktype air circuit breakers, rated current up to 6300A or higher, are the main equipment in low-voltage distribution network to deal with large current.
In addition, since the arc extinguishing medium is air, there is no problem of reducing the crushing capacity caused by the corrosion of vacuum bulb. As long as the arc gate remains intact, the breaking capacity remains the same.
V. Comprehensive Protection Functions – One Unit Does the Work of Four
air circuit breaker combines four protection functions, essentially combining knife switch, fuses, thermal relays and undervoltage relay:
Overload Protection (Thermal Trip): The bimetallic strip can sense a prolonged overcurrent and delay tripping to prevent circuits from overheating.
Short-circuit protection (Electromagnetic Trip): The electromagnetic coil senses a large instantaneous current and jumps in milliseconds to prevent cable from burning.
Undervoltage Protection (Undervoltage Trip Unit): Automatic tripping when the voltage is too low, preventing the equipment from operating abnormally at low voltage.
Normal on/ off: manual or electric off and on, connecting and disconnecting circuits at all times.
Buying an air circuit breaker is equivalent of buying four protective elements at once, saving space, money and wiring.
VI. INTRODUCTION Easy to operate, remote-controlled
air circuit breaker come with accessories:
Electric operation mechanism: press a button to achieve remote closure and opening, do not need to manually operate the lever to the distribution cabinet.
Shunt trip unit: only a control signal can be tripping circuit breaker, with fire alarm linkage, emergency disconnection and other functions.
Auxiliary and alarm contacts: These contacts feed back to PLC or to the monitoring system the the circuit breaker's status (closed/open/fault) for automated management.
These features are highly useful in modern smart distribution systems and are much cheaper to implement using air circuit breakers than other types of circuit breakers.
VII. Green and pollution-free
This is becoming increasingly important today:
Oil pollution and leakage problems were eliminated by not using oil.
No SF6 gas is used, thus eliminating greenhouse gas emissions (SF6 has a greenhouse effect 23,900 times greater than CO2).
No chemical arc-quenching media is used, and post-treatment recovery is simple.
In the context of "dual carbon" (carbon dioxide dioxide, carbon dioxide, carbon emissions), the environmental advantages of air circuit breakers are unparalleled by other types of circuit breakers.
VIII. Simple maintenance and Short Downtime.
The components of air circuit breakers were mechanical, without any high-tech features. Replace the bimetallic bars when they fail, the contact points when they burn out, and the arc fences when they fail. These are standard worn parts that can be replaced on site and do not need to be sent back to the factory for repair.
Instead, if the vacuum bulb of the vacuum circuit breaker fails, the entire device must be sent back to the plant for replacement. SF6 circuit breakers require professional gas leak testing and gas replenishment, while oil circuit breakers require to be replaced and oil filtered. Maintenance cycles and costs are much higher.
IX. The advantages of air circuit breakers can be summed up in one sentence: safety, affordability, durability, versatility, environmental protection and easy maintenance. This is undoubtedly the ``king of value for money"in low-voltage distribution. Air circuit breakers are air circuit breakers switches in domestic distribution boxes, large switches in your factory's distribution cabinet cabinets, and major switches in shopping malls and office buildings. The air circuit breakers have been replaced by SF6 and vacuum circuit breakers in the high-pressure arena, but they are still the unreplaceable kings on the main battlefield of the 380V-690V.
