CB

A pneumatic circuit breaker (CB) is a type of high-voltage circuit breaker that uses compressed air (gas) as the arc-quenching and insulating medium. When a fault occurs, the contacts open, and a powerful blast of compressed air is directed into the contact gap. This high-pressure airflow rapidly cools and sweeps away the ionized gases, effectively extinguishing the electric arc and restoring the insulating strength of the medium, thereby interrupting the current. They are primarily used in high-voltage (HV) applications, such as transmission systems and substations.