Forskellen mellem luftafbryder og vakuumafbryder

Arc Quenching Medium

Air Circuit Breaker (ACB): In the case of a fault or at the time of switching off, the medium of arc extinction is air at atmospheric pressure. The arc cools due to the air present around it.

Vacuum Circuit Breaker (VCB): A high vacuum is used as the arc quenching medium in this type of circuit breaker. An arc is extinguished within a vacuum chamber where the absence of particles facilitates quick arc suppression.

Arc Quenching Method

ACB: Relies on air blast or magnetic blowout for elongation and cooling of the arc. Typically, it is also provided with metal contacts and arc chutes to guide the arc and to control the arc energy.

VCB: When the contacts open, a small arc is formed. This arc, in the vacuum, is quickly extinguished due to condensation of the metal vapor that assists in the quick extinction of an arc without auxiliary cooling mechanisms.

Applications

ACBs: These are normally meant for applications involving low voltage, usually up to about 1 kV, and hence see their usage in commercial and industrial buildings, panel boards, and other low-voltage systems.

VCB: These are mainly applied at medium voltages of up to 36 kV or higher. It is very ideal for substations, industrial plants, and critical systems that demand reliable arc interruption.

Maintenance

ACB: The maintenance has to be done more frequently as the parts are exposed to air, which may cause oxidation and erosion of contacts.

VCCB: Service life is longer, since the vacuum inside reduces the contact wear and contamination. Thus, it requires less maintenance.

Reliability and Strength

ACB: It is not that strong in arc interruption for high current or high voltage conditions, since the air medium may not prevent the re-ignition of the arc at all times.

VCB: Very reliable and robust for arc interruption, owing to efficiency in vacuum to impede arc re-ignition; hence, suitable for frequent operations.

Size and Cost

ACB: In general, bigger in size and more economical in its unit cost for low-voltage applications.

VCB: More compact and energy-saving but usually higher in price because of the vacuum chamber technology applied, and it has been suitable for medium voltage systems.

Summary Table

These differences highlight why ACBs are often chosen for low-voltage applications while VCBs are preferred for medium-voltage applications where durability and reliability are paramount.