What is the effect of the blowout coil on the arc when a contact opens?

• A. Arc dissipates faster
• B. Arc length shortens
• C. Arc energy increases
• D. Arc stops immediately

Answer: (A)

When a contact opens, the current in the circuit wants to keep flowing, so an arc forms. A blowout coil creates a magnetic field that interacts with that arc and pushes it away from the contact area into the arc chute, while stretching it longer. That elongation increases the arc’s impedance and improves cooling, which helps the arc dissipate its energy faster and extinguish sooner. So the effect is that the arc dissipates faster, not that it shortens, increases energy, or stops immediately.