Air circuit breakers are used to protect power lines and electrical equipment against overloads, short circuits, undervoltage conditions and abnormal current flow conditions. Furthermore, they interrupt current in cases where abnormal conditions exist.

An ACB is designed with main and arcing contacts. When the main contacts separate, an arc moves into a chute where it can be safely cooled and extinguished.

Arc Chute

Arc chutes are used in used circuit breakers, Contactors, Isolators and other high current interruption devices to confine, cool and extinguish electric arcs produced when contacts separate. Arcs produce heat which can damage contacts as well as melt them completely if left uncontrolled - thus making its rapid extinguishment an absolute priority - Arc chutes do this by: circuit breaker for sale at surplusrecord.

The arc chute contains an array of metal plates which are mutually insulated from one another and comprised of ferromagnetic materials that attract and magnetize an arc, drawing it closer. As it moves in closer, these shortening plates break up its path into multiple shorter arcs (arc segmentation), increasing arc length while helping cool it. After further progression into the chute it gets extinguished.

Arc chutes not only limit and dissipate arc energy, they also protect main contacts from excessive heat while prolonging switching life at rated currents. Arc chutes typically feature hard materials like silver, cadmium, tungsten or zinc alloys to withstand higher temperatures while remaining hard so as not to degrade over time as quickly. Also, their higher temperature tolerance allows them to interrupt at lower voltage levels for greater safety of operators and equipment alike.

Arc Runner

In certain embodiments, arc runners are used to draw an arc from a stationary contact on a line conductor and direct it toward an arc chute. They typically feature two portions that engage or abut this contact and another that engages a recess on housing for maximum effectiveness.

Arc runners are typically constructed of nonferromagnetic conductive material and feature forward extending segments with spaced out joints that form a gap space, typically on opposing lateral sides of a stationary contact arm/contact contact, to form an arc runner. They may also feature upper portions with spaced apart fingers facing (and being adjacent) the stack 25.

Each finger of an arc runner can have downwardly extending planar walls 40w that protrude downwardly from each fingertip, as shown in FIGS. 7A-7E and 8A-8D. As can be seen from these figures, an arc runner may feature an uncurved lower end portion than seen previously.

Arc runners can feature an upper end portion with spaced-apart fingers that face (and reside adjacent) the stack and taper upward at their forward most end 40e, tapering forward at a forwardmost point 40e of this planar wall arc runner. Finger surfaces should be substantially flat for comfortable usage; additionally, this planar wall may extend downward from planar walls 40w of this arc runner which may feature downwardly extending planar walls 40w for added support when connected to line conductors by brazing, welding, adhesives snap fit features bayonet features or frictional engagement for attachment purposes.

Arch Shoot

Air circuit breakers are widely used for controlling power stations' auxiliary equipment such as industrial plants, capacitors, electrical machines and generators. Furthermore, they protect power distribution networks against fire and explosion risks in indoor environments as well as controlling low voltage devices.

Normal operation for an air circuit breaker involves current flowing through its contacts, with these being disconnected when there is a short circuit. Once disconnected, electromagnetic and thermal effects drive any formed arc towards an arc chute where it cools off before finally dissipating entirely.

An arc chute consists of several metallic plates placed within an equal air gap of an ACB to increase arc length by separating and cooling it, thus intensifying and carrying higher currents.

Air circuit breakers are experiencing fast global growth due to increasing electricity demands across industries and residential applications, especially with smart technologies providing new avenues for remote monitoring of power systems and management. Furthermore, increasing emphasis is placed on safety and reliability within industries; driving demand for air circuit breakers that protect systems against overcurrents or short circuits.

Arcing Contacts

To control an arc, a circuit breaker must differentiate its resistance-to-arc role from its current carrying function. This is typically accomplished using tungsten alloy-based contacts called "arcing contacts" that close first upon closing and open last upon opening; they do not come into direct contact with the arc, therefore do not erode. An arc is drawn between these contacts through both thermal and electromagnetic action before traveling along an arc runner and being split up using splitting plates; additionally these arcing contacts conduct any decomposition products from an arc so that at natural current zero concentration of SO 2, SOF 2, and CS 2 reduces as opposed to before contact erosion occurred.

These arcing contacts are made from hard, heat resistant copper with silver plating on either main or auxiliary contacts, designed to withstand high current interruption, but their lifespan is limited due to erosion caused by arcing processes. Miniature and molded case circuit breakers typically feature replaceable main contacts; power and SF6 circuit breakers may have fixed or replaceable main and auxiliary contacts that must remain permanently in place for proper function.

Air circuit breakers differ from oil circuit breakers in that they utilize blowout coils which provide magnetic control of arc lengthening at its contacts, rather than traditional arc blowout mechanisms used in oil circuit breakers. This type of arc quenching may prove more efficient for safety as it reduces chances of arcing occurring at unsafe spots while guaranteeing that its proper location will be reached and its arc will be extinguished quickly and safely.