What does Air Circuit Breaker?
Air Circuit Breaker (ACB) is an electrical device used to provide Over-current and short-circuit protection for electric circuits from 200 Amps to 6300 Amps. These are usually used in low voltage applications below 690V, but some special application needs meet 1000V, such as, photovoltaic power generation. Nader manufacture NDW2-4000 series and NDW3 series can meet 1000V AC.
Air circuit breakers operate with their contacts in free air. Their method of arc quenching control is entirely different from that of oil circuit-breakers. They are always used for a low-voltage interruption and now trends to replace high-voltage oil breakers.
How to work Air Circuit Breaker?
Air Circuit breakers generally have two pairs of contacts. The main pair of contacts one carries the current at normal load and these contacts are made of copper metal. The second pair is the arcing contact two and is made of carbon. When the circuit breaker is being opened, the main contacts open first. When the main contacts opened the arcing contacts are still in touch with each other. As the current gets a parallel low resistive path through the arcing contact, during the opening of the main contacts, there will not be any arcing in the main contact. The arcing is only initiated when finally the arcing contacts are separated. Each of the arc contacts is fitted with an arc runner which helps, the arc discharge to move upward due to both thermal and electromagnetic effects.
The arc in the chute will become colder, lengthen, and split hence arc voltage becomes much larger than the system voltage at the time of operation of an air circuit breaker, and therefore the arc is extinguished finally during the current zero.
How many types of air circuit breakers are there?
There are mainly two types of ACB, 3 poles air circuit breaker and 4 poles air circuit breaker.
How do I choose an air circuit breaker?
The current-carrying capacity (In, A) of the breaker should be higher than the expected load in the circuit. ABCs are available 200 up to 6300A, but become less cost-effective for very large ratings (2000A and above). The advantage of ACBs for very large ratings is their big current and breaking capability.