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The medium employed for extinction of arc in air circuit breaker is
SF6
Oil
Air
Water
Air
An Air Circuit Breaker (ACB) utilizes atmospheric air as the arc quenching medium. When the contacts separate, the arc is elongated and cooled by the surrounding air to achieve current interruption.
An Air Circuit Breaker (ACB) utilizes atmospheric air as the arc quenching medium. When the contacts separate, the arc is elongated and cooled by the surrounding air to achieve current interruption.
VarcтАЛ=VaтАЛ+VcтАЛ+ElтАЛ тАФ where VaтАЛ,VcтАЛ are electrode drops and E is the gradient per unit length
RarcтАЛ=IarcтАЛVarcтАЛтАЛ тАФ relationship between arc resistance and current
As the contacts separate, the air between them becomes ionized due to the high temperature of the arc. To extinguish the arc, the breaker forces the arc into an 'arc chute' containing metallic splitter plates; this splits the arc into smaller series segments, increasing the effective arc voltage and cooling the plasma until extinction.
ACBs are primarily used in low-voltage distribution systems (up to 660V).
Uses high-pressure air blast or natural atmospheric air to elongate the arc.
Splitter plates increase the effective arc length and cooling surface area.
Non-inflammable medium
Simple maintenance and inspection
No risk of explosion
Not suitable for very high voltages
Requires large space due to bulky arc chutes
Higher noise level during operation
Low-voltage AC distribution panels
Industrial motor control centers
Power station auxiliary equipment
Option A (SF6) is used in high-voltage gas-insulated switchgear.
Option B (Oil) was used in legacy designs but poses fire risks.
ACBs are typically limited to voltages below 1kV.
C is correct тАФ Air Circuit Breakers use atmospheric air to cool and split the electric arc for interruption.
Always remember that Circuit Breaker classification is primarily based on the arc extinguishing medium; for low voltage, air is preferred, while for high voltage, SF6 or Vacuum is preferred.