Top 10 Vacuum Interrupter Brand & Manufacturers

What is a Vacuum Interrupter?

A vacuum interrupter is a key component in high - voltage electrical switching equipment. It is a device that uses a vacuum as the insulating medium to interrupt the flow of electric current. Essentially, it consists of a sealed vacuum chamber that contains a pair of electrodes. When the current - carrying contacts are separated, an arc is formed between them. The vacuum environment in the interrupter allows for rapid quenching of this arc, thereby effectively interrupting the current flow and providing a reliable means of switching in high - voltage applications.

History of Vacuum Interrupter

• Early Origins: The concept of using a vacuum for electrical insulation and current interruption dates back to the early 20th century. However, the early designs were not very practical due to limitations in vacuum - sealing technology and understanding of arc behavior in a vacuum. Initial attempts were mainly in the laboratory setting, exploring the possibility of using vacuum as an alternative to other insulating media like oil or air.
• Development and Refinement: In the mid - 20th century, significant advancements were made in vacuum - sealing techniques and materials science. This led to the development of more reliable vacuum interrupters. The understanding of the physics of arc formation and quenching in a vacuum environment also improved. These developments enabled the use of vacuum interrupters in a wider range of applications, such as medium - voltage switchgear.
• Modern Developments: In modern times, vacuum interrupters have seen continuous improvements. The use of advanced materials for electrodes and the optimization of the vacuum chamber design have led to higher voltage - handling capabilities and longer service lives. They are now an integral part of high - voltage power - distribution systems and various industrial applications, with enhanced performance in terms of current - interrupting capacity and dielectric strength.

Purpose of Vacuum Interrupter

• Current Interruption: The primary purpose of a vacuum interrupter is to break or interrupt the flow of electric current in a circuit. This is crucial in power - distribution systems when a circuit needs to be opened, such as during maintenance, fault - isolation, or load - switching operations. The ability to quickly and reliably interrupt high - voltage and high - current circuits is essential for the safety and proper operation of the electrical grid.
• Arc Quenching: When the contacts of a switch open, an arc is formed due to the ionization of the medium between the contacts. In a vacuum interrupter, the vacuum environment provides excellent arc - quenching properties. The lack of a gas - based medium means that the arc is quickly extinguished as there are no ion - generating substances. This rapid arc quenching helps to reduce the energy dissipated during the switching process and minimizes the damage to the contacts.
• Insulation and Dielectric Strength: The vacuum serves as an effective insulator. It provides a high dielectric strength, which means it can withstand high voltages without allowing current to leak through. This insulation property is vital for maintaining the integrity of the circuit when the switch is in the open state and for preventing flashovers and other electrical breakdowns.

Principle of Vacuum Interrupter

• Arc Formation and Initial Phase: When the contacts of the vacuum interrupter start to separate and the current is being interrupted, an arc is initially formed. The arc is a plasma column of ionized metal vapor from the contacts. As the contacts separate further, the arc is stretched, and the energy density in the arc column changes. In a vacuum, the lack of a gaseous medium restricts the supply of new ions to sustain the arc, which is a key factor in the arc - quenching process.
• Arc Quenching Mechanism: The high - temperature plasma of the arc causes the metal vapor to be ejected from the contact surfaces. In a vacuum, the metal vapor quickly diffuses and cools, leading to a rapid decrease in the ion density. As the ion density decreases, the conductivity of the arc path reduces, and the arc is quenched. The vacuum interrupter's design, including the shape and material of the contacts and the vacuum chamber, is optimized to enhance this arc - quenching process.
• Dielectric Recovery: After the arc is quenched, the vacuum interrupter must quickly recover its dielectric strength. The vacuum environment allows for a rapid recovery of the insulating properties. The absence of residual ionized gases and the quick dissipation of the metal vapor ensure that the interrupter can withstand the system voltage again shortly after the current interruption.

Features of Vacuum Interrupter

• High - Voltage and High - Current Handling: Vacuum interrupters are designed to handle high voltages (up to several tens of kilovolts) and high currents (thousands of amperes). Their construction and the use of vacuum insulation enable them to operate under such extreme conditions, making them suitable for applications in power - transmission and - distribution systems.
• Long Service Life: Due to the absence of a corrosive or deteriorating insulating medium (unlike oil - filled or air - insulated switches), vacuum interrupters generally have a long service life. The contacts and the vacuum chamber can withstand a large number of switching operations without significant degradation, reducing the need for frequent maintenance and replacement.
• Compact Design: Vacuum interrupters have a relatively compact design compared to some other types of switching devices. The use of vacuum as an insulator allows for a smaller overall size, which is beneficial for space - constrained applications such as in switchgear cabinets and substations.
• Low Maintenance: They require less maintenance compared to traditional switching devices. There is no need to replace or monitor an insulating oil or deal with air - quality - related issues. The main maintenance tasks usually involve checking the mechanical integrity of the contacts and the vacuum seal, which can be done less frequently.
• Environmental Friendliness: Vacuum interrupters are more environmentally friendly than some other switching technologies. There is no risk of oil leakage or contamination, and they do not release harmful gases during operation. This makes them a preferred choice in applications where environmental concerns are important.

Types of Vacuum Interrupter

• Axial Magnetic Field (AMF) Vacuum Interrupter: In this type, an axial magnetic field is generated around the contacts during the arc - formation stage. The magnetic field causes the arc to rotate, which helps in evenly distributing the heat and energy of the arc. This type is effective in handling high - current interruptions and is commonly used in medium - to high - voltage applications.
• Transverse Magnetic Field (TMF) Vacuum Interrupter: Here, a transverse magnetic field is used to control the arc behavior. The magnetic field is perpendicular to the axis of the contacts and helps in driving the arc in a specific direction. TMF vacuum interrupters are suitable for applications where the current - interrupting requirements are more complex and where a more precise control of the arc is needed.
• Self - Blast Vacuum Interrupter: These interrupters use the energy of the arc itself to create a pressure - differential that aids in the arc - quenching process. The arc - generated gas pressure helps in expelling the ionized metal vapor and enhancing the dielectric recovery. Self - blast vacuum interrupters are often used in applications where a quick and efficient arc - quenching mechanism is required.

Precautions for using Vacuum Interrupter

• Proper Installation: Vacuum interrupters must be installed correctly according to the manufacturer's instructions. The installation process should ensure that the mechanical and electrical connections are secure and that the interrupter is properly aligned. Incorrect installation can lead to poor contact performance, increased arcing, and reduced service life.
• Vacuum Integrity Check: Regularly check the vacuum integrity of the interrupter. A loss of vacuum can significantly affect the performance of the device. Use appropriate vacuum - testing equipment to monitor the vacuum level and look for signs of vacuum leakage, such as a decrease in dielectric strength or abnormal arcing behavior.
• Contact Wear and Erosion: Although vacuum interrupters have a long service life, the contacts can still experience wear and erosion over time due to the arcing process. Monitor the contact condition through visual inspection and electrical testing. Replace the contacts if the wear exceeds the acceptable limit to ensure reliable current - interruption performance.
• Over - Voltage and Over - Current Protection: Even though vacuum interrupters can handle high voltages and currents, they still need to be protected from excessive over - voltages and over - currents. Install appropriate surge - arresters and over - current - protection devices in the circuit to prevent damage to the interrupter during abnormal operating conditions.
• Environmental Conditions: While vacuum interrupters are relatively less affected by the environment compared to other switching devices, extreme environmental conditions such as high humidity, temperature fluctuations, and corrosive atmospheres can still have an impact. Consider using appropriate enclosures or protective measures to shield the interrupter from such conditions.[!--empirenews.page--]

Things to consider when purchasing Vacuum Interrupter

• Voltage and Current Ratings: Determine the maximum voltage and current that the vacuum interrupter will need to handle in your application. Make sure to choose a device with appropriate voltage - and current - handling capabilities, with some margin for safety and future expansion of the system.
• Type of Interrupter: Select the most suitable type of vacuum interrupter based on your specific requirements. Consider factors such as the current - interrupting mechanism (AMF, TMF, or self - blast), the application's complexity, and the expected arc - handling requirements. Different types have different advantages in terms of arc control and current - interruption performance.
• Service Life and Maintenance Requirements: Look for a vacuum interrupter with a long - expected service life and minimal maintenance requirements. Consider the cost and complexity of maintenance tasks such as contact replacement and vacuum - integrity checking. A device with a longer service life and easier maintenance can reduce the overall cost and downtime of the system.
• Compactness and Space Constraints: If space is a concern in your installation, choose a vacuum interrupter with a compact design. Ensure that the physical dimensions of the device fit well within the available space in your switchgear or other equipment.
• Environmental Compatibility: Consider the operating environment of the vacuum interrupter. If it will be exposed to harsh conditions such as high humidity, corrosive chemicals, or extreme temperatures, choose a device that can withstand such conditions or look for appropriate protection methods.
• Cost: Establish a budget for the purchase of the vacuum interrupter. The cost can vary depending on the voltage and current ratings, the type of interrupter, and other features. Consider not only the initial purchase price but also the long - term costs, such as maintenance and potential replacement costs. A more expensive, high - quality interrupter may be a more cost - effective choice in the long run if it offers better performance and a longer lifespan.
• Brand and Reputation: Choose a reputable brand with a good track record in manufacturing vacuum interrupters. Read customer reviews and ask for recommendations from other users or industry experts to assess the quality, reliability, and performance of different models. A well - known brand is more likely to provide reliable customer service and replacement parts.

Terms of Vacuum Interrupter

• Dielectric Strength: The ability of the vacuum interrupter to withstand an electric field without breakdown. It is usually measured in kilovolts per millimeter (kV/mm) and is a crucial parameter for determining the maximum voltage that the interrupter can handle.
• Arc Voltage: The voltage that appears across the contacts during the arcing process. The arc voltage affects the energy dissipated in the arc and the overall performance of the current - interruption process. Understanding and controlling the arc voltage is important for the efficient operation of the vacuum interrupter.
• Interrupting Capacity: The maximum current that the vacuum interrupter can interrupt under specific conditions. It is usually specified in kiloamperes (kA) and is a key factor in determining the suitability of the interrupter for a particular application.
• Contact Material: The material used for the contacts of the vacuum interrupter plays a significant role in its performance. The contact material affects the arcing behavior, wear rate, and the ability to withstand high - current and high - temperature conditions. Commonly used contact materials include copper - chromium alloys and other high - conductivity and high - melting - point materials.
• Vacuum Pressure: The level of vacuum inside the interrupter chamber. Maintaining a proper vacuum pressure is essential for the device's performance. The vacuum pressure affects the arc - quenching ability and the dielectric strength of the interrupter.