Final answer:
The transient voltage across breaker contacts following arc extinction is called recovery voltage. It is crucial for circuit breaker design to prevent restriking, where the arc attempts to re-establish itself. Option 1 is correct.
Step-by-step explanation:
The resultant transient voltage which appears across the breaker contacts at the instant of arc extinction is known as the recovery voltage. This voltage is the potential across the contacts of the breaker after the arc has been extinguished and the current has been interrupted.
It is a critical parameter for the design and selection of circuit breakers in electrical engineering, as it determines the ability of the breaker to withstand the voltage without re-igniting the arc, which could lead to a condition known as restriking voltage.
Restriking voltage is the voltage that appears across the contacts during the transient period when the arc is attempting to re-establish itself after a current zero in an alternating current cycle. For successful interruption of the current, the recovery voltage must be below the level at which the gas between the contacts can ionize and allow the arc to reform.