Indoor Vacuum Circuit Breaker

A: An air circuit breaker is a type of circuit breaker that uses air as the arc quenching medium. A vacuum circuit breaker is a type of circuit breaker that uses vacuum as the air quenching medium. ACB is suitable for low voltage range up to 450 volts. VCB is suitable for medium voltage range from 11 kV to 33 kV.

A: A breaker that uses a vacuum as an arc quenching medium is called a vacuum circuit breaker. The arc is extinct as the contacts are separated in a high vacuum. It is mainly used for medium voltage ranging from 22 kV to 66 kV.

A: The vacuum circuit breakers can be reliable in cases of providing high insulating strength. Therefore, they carry better arc quenching features than other methods. Vacuum circuit breakers have a longer life, therefore, they can make a good investment, and can be reliable as well.

A: The Earthing Switch is a manually operated device with safety interlocking keys. It is a safety device designed to ground electrical circuits on both sides of the AC Vacuum Circuit Breaker when the AC Vacuum Circuit breaker is open.

A: You can expect longer service life in case you are using VCB over other types of circuit breakers. Unlike oil circuit breakers, you don’t have to worry about fire mishaps while using vacuum circuit breakers. Your VCB panel is environmentally friendly and user-friendly. There is no complexity faced by the user or engineer while replacing a faulty or damaged vacuum interrupter.

A: Vacuum circuit breaker or VCB works when the current exceeds its rated value. In other words, the circuit breaker will be operated if there is an overload current in the system. Inside the circuit breaker, it is a vacuum, therefore arc formation within the circuit breaker is totally extinguished and cannot occur due to the absence of moisture or ionization particles.

A: You check the vacuum on the vacuum breaker using three tests: (1) the contact resistance test, (2) the high potential withstand test, and (3) the leak-rate test. Also, you can check by observing it from the outside, if the enclosed glass looks blurry compared to the initial time, then you can say that the degree of vacuum inside the breaker is reduced.

A: VCB is considered one of the most reliable current interruption technologies for medium-voltage current switchgear. A vacuum circuit breaker has many advantages such as high-cost life, high efficiency, safety, long operation life, and high interruption capacity. Due to its high performance and low performance compared to the other technologies, new promising products are on their way. For the past years, vacuum circuit breaker technology has been on the rise, even though its applications are not feasible at high commercial levels, it is highly suitable for medium-voltage applications. It does not produce any harmful gases like in the case of SF6 circuit breakers. Hence, they are ideal for the environment and humans. The scope of the vacuum circuit breaker is likely to increase in the future because of the high accessibility and simple circuit mechanism.

A: When the circuit breaks due to any reason, the moving contacts move away from the fixed contact and this produces an arc between the contacts. The arc is produced by the ionization of the metal ions and the reaction depends on the material of the contacts. When the contacts separate, they release metallic vapor that fills in the space. The vapors have positive ions from the contacts’ materials. The vapors help in the elimination of the arc. The rate of vapor release depends upon the rate of current. When the current starts to decrease, the level of vapors also decreases. Gradually the current decreases to zero, and so does the rate of vapors. This leads to the medium regaining its dielectric strength. When the current voltage is high, the arc is condensed in a small region. This leads to swift vaporization of the surface. When the arc is in a diffused stage, the interruption is possible. Otherwise, the arc will strike again. After the arc is interrupted finally, the dielectric strength builds up rapidly which is uncanny of the vacuum breaker. High voltage vacuum circuit breakers are ideal for capacitor switching and perform free from re-strikes. The whole process of arc extinction is highly influenced by the shape and material of the contacts: Fixed contact and Moving contact. It also depends on how the metal vapor condenses. This is all about vacuum circuit breaker construction and working.

A: Vacuum circuit breakers, also known as VCBs, use a vacuum to extinguish the arc created when the circuit is tripped and the contacts move apart. VCBs work quickly and effectively, making them a solid choice for medium- and high-voltage systems.

A: The indoor vacuum circuit breaker is generally used in the switch cabinet, mainly used to break the current. The outdoor high voltage vacuum circuit breaker is larger than the indoor circuit breaker. The height of the bare conductor to the ground is greater than 2.5 meters, 0.125 meters.

A: The moving and stationary contacts are kept open air in a sealed package in an air circuit breaker. Thus, the arc is quenched by air every time the circuit breaker opens. Air circuit breakers are easily ionized because it contains less air, and air acts as the dielectric medium. However, the vacuum acts as the arc quenching medium in a VCB. The ability of a vacuum circuit breaker to break short circuits is pretty impressive since free electrons cannot exist in the presence of a vacuum.

A: VCBs have many applications, and various industries can use them, including power plants, commercial and manufacturing buildings and industrial plants. They work well in both medium- and high-voltage systems and are typically considered the most reliable option. When dealing with sensitive and expensive equipment, it is essential to have a device that will consistently and quickly extinguish the arc. Equipment and even lives could be at stake. VCBs are particularly useful in volatile situations where a breaker is tripped often and needs to be reset quickly. A VCB can recover quickly, often saving time and money. They also work well in situations with high voltage and low currents. VCBs work best in a range of 11 to 33 kV. High-voltage circuit breakers often use SF6 gas as an insulator to extinguish the arc. While effective, SF6 is harmful to the environment in the event of a leak. As VCB technology advances, they likely will replace many SF6 breakers in high voltage systems. VCBs are also capable of interrupting DC currents. They are highly effective and can often do so in a compact vessel.

A: Pros
● VCBs are safer than circuit breakers that use other insulating mediums like oil or air blast. There is less chance of a fire or explosion, and they do not use any harmful chemicals.
● VCBs have a long life. When well-constructed, they require very little maintenance and you will not have to replace them as often.
● A vacuum is one of the most effective dielectric mediums. It can quickly extinguish an arc and rest for frequent use.
Cons
● While VCBs are affordable, their cost increases with higher voltages. They may need to be more economical for extremely high voltages.
● While damage or malfunctioning is unlikely, VCBs can be challenging to fix. They typically cannot be repaired on-site.

A: You can expect longer service life just in case you're exploiting VCB over different styles of circuit breakers. In contrast to oil circuit breakers, you don’t have to worry about fireplace mishaps while using vacuum circuit breakers. Your VCB panel is environmentally friendly and easy.

A: A vacuum circuit breaker is one that uses a vacuum to quench the arc in a circuit breaker. Because of its aesthetic features, the vacuum enhanced arc has a strong insulation power. The majority of these can be used in normal voltage applications. Despite the fact that it is not commercially viable, this technology was created specifically for high-voltage applications. Within the vacuum chamber of the breaker, the current-carrying conductor and its accompanying arc interruption are regulated. A vacuum interrupter is what it’s called. In the heart of this resistively symmetric ceramic insulator lies a metal arc chamber.

A: ● Frequency withstand voltage method. Make the circuit breaker in the disconnected state, add voltage between the contacts of the vacuum interrupter chamber to determine, can withstand 42kV, Imin frequency withstand voltage test, the vacuum bubble should not have a continuous discharge, then considered normal.
● Vacuum tester test. At present, the more accurate method is the magnetic control method, suitable for the manufacturer as a vacuum interrupter detection. The vacuum degree is not more than 5*10-4Pa.
● Spark meter method. Only for the glass tube vacuum interrupter, when using, let the spark detector in the interrupter surface movement, in its high-frequency electric field under the action of different internal luminescence. If there is a light green glow inside the tube, then the vacuum degree is above 1.33 * 10-5; if the red and blue light, that the tube has failed; if the tube has been in the atmosphere, it will not glow.

A: The vacuum bubble needs to be replaced if
● when the vacuum interrupter has reached the guaranteed number of interruptions by the manufacturer (mechanical life I million times).
● The vacuum interrupter has reached the specified inspection cycle (when the number of divisions and closures reaches I million times and the short-circuit current reaches 100 times, the interrupter's voltage test is conducted and the vacuum interrupter is replaced when it reaches 20,000 times).
● When abnormalities are found in the appearance. Inspection basis: The life of vacuum circuit breaker is judged by 2 indicators of contact and vacuum degree.

A: Control parts Control parts are an indispensable part of operating circuit breakers. Mainly check whether the terminals are loose and discolored, whether the micro switch and auxiliary switch are in place, and whether the contacts are burnt out. The insulation resistance of each electrical and control circuit element shall not be less than 2mΩ. There should be no obvious difference between the DC resistance value of the opening and closing coil and the closing contactor coil and the product factory test value. If there is a handheld remote control device, the remote control test should be carried out, and the linear remote control distance is generally not less than 8m.

A: The high-voltage vacuum circuit breakers are designed and manufactured in accordance with latest IEC standard, IEC 60056, IEC 2300, and for indoor switchgear purposes. The circuit breakers shall be applied according to normal service conditions specified.