ARC FLASH ELIMINATION APPARATUS AND METHOD

PROBLEM TO BE SOLVED: To provide an apparatus preventing and reducing arc flashes; and its method. SOLUTION: An arc crowbar is provided with electrodes 34A, 34B and 34C separated by a gap 35 in a protective case. Each electrode is connected to an electrically different conductor of a circuit. A sensor 42, 44 detects an arc flash condition on the circuit and signals a trigger circuit 52 to send an electrical pulse to an arc-triggering device 36 in the arc crowbar gap. The triggering device ionizes a portion of the gas between the electrodes, initiating a protective arc between the electrodes that absorbs energy from the power circuit and trips a breaker, eliminating the arc flash condition. The triggering device may be a plasma gun, especially one that injects plasma of an ablated material into the gap. The sensor may signal a circuit breaker 26 to open in the power circuit. COPYRIGHT: (C)2009,JPO&INPIT