VINCENT C OXLEY
Engineering in Waltham, MA
License number
Massachusetts 25807
Expiration Date
Jun 30, 1992
Type
Electronic Engineer
Address
Address
Waltham, MA 02454
Professional information
Current Monitoring Apparatus
US Patent:
4428021, Jan 24, 1984
Filed:
Aug 6, 1982
Appl. No.:
6/405818
Inventors:
Wen T. Chen - West Newton MA
Vincent C. Oxley - Waltham MA
Vincent C. Oxley - Waltham MA
Assignee:
GTE Laboratories Incorporated - Waltham MA
International Classification:
H02H 902, H02H 300
US Classification:
361 94
Abstract:
Apparatus for monitoring the fault current in the ground conductor of a polyphase AC electrical power system. When the fault current exceeds a predetermined level, the magnetic field produced causes a magnetic reed switch to close and open at twice the AC frequency. Pulse producing circuitry connected to the reed switch responds to the switch action to produce pulses at the same frequency. The pulses are counted by logic circuitry, and when a predetermined number of pulses have been counted, an output signal triggers circuitry which trips circuit breaker apparatus in the power system. The delay period between first detecting the fault current and tripping of the circuit breaker apparatus can be adjusted by changing the number of pulses to be counted by the logic circuitry before it produces an output signal.