How Does a Vacuum Circuit Breaker Work

Submitted by Kristian on Fri, 03/31/2023 - 06:21

How Does a Vacuum Circuit Breaker WorkA vacuum circuit breaker is a device that helps to prevent unintended currents caused by short circuits in electrical systems. It works by interrupting the current after a fault has been detected, thereby preventing damage to the system. Vacuum interrupter technology was first introduced in 1960, and since then, it has seen significant improvements in size reduction due to advancements in engineering capabilities.

After the contacts of a vacuum circuit breaker are opened within the vacuum, an arc is generated due to metal vapor ionization in the contacts. But this arc can be extinguished quickly as electrons, ions, and metallic vapors produced during it condense over the outside of the circuit breaker contacts, restoring their dielectric strength. This quick recovery rate of dielectric strength is an essential feature that makes vacuum circuit breakers more efficient than other types of breakers.

The arc quenching process in vacuum circuit breakers also helps reduce maintenance costs since this type of circuit breaker does not need to be replaced nearly as often as other types. These systems are ideal for use in medium voltage applications where safety is critical, and reliability should remain at maximum levels over long periods without replacement or maintenance costs.

The arc is produced due to the ionization of metal ions, and its characteristics depend very much on the material of these contacts.

In terms of arc interruption, it works differently than other circuit breakers. When the contacts separate, the vapor is released and filled instead in the contact space. It consists of positive ions liberated from the contact material, and its density depends on the current in the arc. However, after reaching current zero, if the vapor density is reduced, it regains its dielectric strength

Working Principle

Multiple parallel arcs form for small currents in vacuum circuit breakers, dividing the total current into many paths that repel each other while spreading over contact surfaces. This process is known as a "diffused arc," which can be quickly interrupted due to its nature. Moreover, such vacuum circuit breakers have higher resistance towards thermal stresses caused by overloads and less maintenance required for optimal operation since no arcing or sputtering products accumulate on their contacts like with other circuit breakers.

Current chopping in vacuum circuit breakers mainly depends on the pressure of vapor and the properties of electron emission in contact material. As a result, it is also influenced by the thermal conductivity of this material — the lower the thermal conductivity, the lower the chopping level. It is possible to reduce current chopping levels by selecting a contact material with ample metal vapor that allows the current to reach a shallow value. However, it should be used cautiously since it can negatively affect dielectric power.

Overall, vacuum circuit breakers are highly efficient and reliable compared to other circuit breakers and offer reduced maintenance costs due to their long lifespan before repair or cleaning is needed. Their quick improvement rate in dielectric strength also helps reduce arc interruption times. It makes them ideal for use in medium voltage applications where safety is critical while reliability remains at maximum levels over long periods without replacement or extra maintenance costs.

Contact Us Today

If you're in the mining industry and looking for a reliable and safe way to protect your electrical equipment, consider the vacuum circuit breakers from Becker Mining. These high-quality breakers offer superior performance and durability, ensuring that your equipment stays protected against dangerous electrical faults.

With a range of models to choose from, Becker Mining's vacuum circuit breakers are designed to meet the specific needs of the mining industry. Contact us today and learn how vacuum circuit breakers can help keep your mining operations running smoothly and safely.

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