Vacuum circuit breakers (VCBs) use a vacuum to interrupt arcs, unlike air circuit breakers and molded circuit breakers. This enables them to have a long life and offers greater safety for the operative personnel.
VCBs are oil-free equipment that has a higher dielectric strength than other types of breakers. When the contacts separate, they release a vapor that comprises positive ions. This vapor density depends on the current. Circuit breaker for sale at surplusrecord.
Used Circuit Breakers
While air circuit breakers and vacuum circuit breakers are both essential components for transmission lines, one performs much better in terms of handling line spikes and surges. Vacuum circuit breakers also require less maintenance than their counterparts, and they are safer to use due to the fact that there is no arcing between the contacts. This makes them ideal for electrical systems that need to be accessed frequently.
Vacuum circuit breakers and used circuit breaker use a combination of elements to create a safe arc-interrupting environment. Some of these devices are filled with special oil that prevents the arc from taking place, while others utilize an ionizing agent to sever the connections between the contacts. Once these elements are sever, electricity is no longer able to flow through the system. The arc is then extinguished by a vapor that is created when the contacts separate from each other.
These devices are commonly used in industrial and mining organizations, power plants, substations, and other high-voltage electrical equipment. They are available in center cabinets, double-layer cabinets, and fixed cabinets.
If you’re in the market for a new or used vacuum or air circuit breaker, contact National Power Equipment today. We offer a wide range of used circuit breakers to suit your needs, and we can also help you select the best type for your specific application. We also provide a comprehensive rental program to ensure your facility always has a spare in the event of an emergency.
Molded Breakers
Molded circuit breakers (MCCB) are a type of electrical device that protects against overload and short circuit. They contain all components within an insulated case and can be used in residential, commercial and industrial systems. They can also be mounted in a number of positions, including vertical, horizontal and up/down.
There are many different types of MCCBs, and each has its own unique tripping characteristics. The differences are usually related to the breaker’s trip curve and its tripping capability. For example, a type B MCCB will trip when it detects a current that is 3-5 times its rated current. This is important for ensuring that the breaker can protect the system from dangerous overloads.
Typically, a molded case circuit breaker has several components, including the mold case, terminals, operating apparatus, and the trip unit. The operating apparatus is the device that controls and operates the breaker, while the trip unit is the mechanism that trips it. There are various types of trip units available, including electromechanical-magnetic and thermal magnetic. In addition, some breaker models may feature electronic trip elements, which offer additional features and flexibility.
The global molded case circuit breakers market is growing at a fast pace due to rapid urbanization and industrialization in the LAMEA region. Additionally, an increase in investment in power generation projects to expand the power infrastructure is boosting the growth of this market.
Vacuum Circuit Breakers
Vacuum circuit breakers have high interruption capability, long operational life, safety and good cost-performance. They are usually used in medium voltage power systems up to 38,000 volts. They are also popular in generator switchgears because of their high interruption capacity and good arc quenching ability.
Unlike oil circuit breakers and SF6 breaker, vacuum circuit breakers do not use any gas for arc quenching. The arc is broken by ionization of metal vapors on the contacts in the vacuum chamber which is kept at a vacuum pressure between 10-7 and 10-5 torr. After the arc is broken, the dielectric strength of the contacts recovers quickly and the arc is extinguished.
The advantage of vacuum circuit breakers is that they are able to interrupt currents at the very first contact separation. This is because they have a much higher insulation strength than other circuit breaker types. Additionally, they can achieve a very low contact surface temperature which makes them safe to operate in high temperatures.
Vacuum circuit breakers also have the benefit of requiring less maintenance than other types of breaker. They do not need to be refilled with gas or oil and they do not require an auxiliary oil system or oil handling. This also means that they are environmentally friendly and do not emit greenhouse gases. Moreover, their external envelope is constructed of glass which helps in the examination of the entire unit from outside after operation. This is done to ensure that a proper vacuum is maintained. If the glass turns milky from its original silvery mirror shine, it means that a loss of vacuum has occurred.
Air Circuit Breakers
Air circuit breakers are a type of electrical circuit breaker that uses compressed air to perform its opening and closing actions. They are a reliable choice for preventing damage to electrical components from overloads and short circuits. They can be used in residential, commercial, and industrial applications. They also offer a variety of benefits, including low maintenance costs and high fault current ratings.
The arc interruption process in a vacuum circuit breaker is different from that of other types of circuit breakers. The difference lies in the material that is used for the current-carrying contacts, which determines the way the arc interrupter works. It is best suited for applications with low voltages, and it has very good short circuit breaking capacity. It is a popular choice for industrial and mining organizations, power plants, and electrical substations.
There are two main kinds of air circuit breakers: axial blast and cross-blast. The axial blast ACB has a fixed contact and a moving contact that are connected by an arcing probe. When a failure occurs, the arc is broken by an axial blow of air, which pushes it into a chute consisting of arc splitters and baffles that prevent the arc from resuming.
The cross-blast ACB has a fixed contact and arcing rings that are attached to a rotating support. When a failure occurs, the ring is pushed into a chute by an air blast. The arc is then separated from the contacts and stretched until it is extinguished. The cross-blast also allows the breaker to operate reliably in heavy fault current conditions.