摘要 |
<p>An electrical system includes first, second and third power busses; a first interrupter electrically connected between the first and second power busses; a second interrupter electrically connected between the second and third power busses; at least one of a shorting apparatus operatively associated with the second power bus, and the first interrupter comprising a trip coil; a current sensor to sense a fault current of at least a predetermined magnitude flowing in the second power bus and responsively output a first signal; a number of light sensors to sense an arc flash operatively associated with a number of the second and third power busses and responsively output a second signal; and a circuit to delay and invert the first signal to provide a third signal, and to operate the at least one of the shorting apparatus and trip coil responsive to an AND of the first, second and third signals.</p> |