Inventors:
Irving A. Gibbs - Fletcher NC
Charles R. Mummert - Hendersonville NC
Assignee:
Eaton Corporation - Cleveland OH
International Classification:
H02H 7125
Abstract:
An excitation control system includes a circuit breaker, a bridge and a controller. The bridge converts AC phases from the breaker to an excitation voltage. The controller includes an output to open the breaker, a first sub-system inputting voltages corresponding to the AC phases and outputting a sensed voltage, and a second sub-system inputting the excitation voltage and outputting a sensed excitation voltage. A first function detects a trip signal and responsively outputs firing signals to the bridge to provide a negative excitation voltage. A second function determines if a threshold is greater than the sensed voltage and if the trip signal is asserted, and responsively asserts the output to open the breaker. A third function determines if the trip signal is asserted and responsively delays for a predetermined time, unless a negative threshold is greater than the sensed excitation voltage, and after the predetermined time responsively asserts the output.