H - Electricity – 02 – H
Patent
H - Electricity
02
H
348/26
H02H 3/093 (2006.01)
Patent
CA 1255782
RMD-1268 MICROPROCESSOR CONTROLLED CIRCUIT BREAKER TRIP UNIT ABSTRACT OF THE DISCLOSURE A microprocessor based trip unit for a circuit breaker is disclosed. The instantaneous current magnitudes in each phase and in the neutral of the circuit being pro- tected are simultaneously and sequentially sampled by re- spective sample and hold circuits. The measured values are then applied to a respective analog-to-digital converter and the digitized values are sequentially applied to a microprocessor. The microprocessor calculates true RMS current and sums the signals of all phases and neutral to determine presence and magnitude of a ground fault current. To permit use of an 8-bit microprocessor, while maintaining high resolution of measured current over a large range, novel automatic scale adjustment is provided. The memory of prior thermal history of the circuit breaker is provided electronically by a capacitor circuit which is discharged at a rate representative of the rate of cooling of the cir- cuit breaker. The output of he capacitor circuit is loaded into the microprocessor when the circuit breaker comes back onto the line after a prior opening operation. Any desired number of trip units can be remotely located from a switch- board frame containing a respective plurality of circuit breakers without local trip units.
491504
Alexander James O.
King William A.
May William E.
Pardue von G.
Fetherstonhaugh & Co.
Siemens-Allis Inc.
LandOfFree
Microprocessor controlled circuit breaker trip unit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Microprocessor controlled circuit breaker trip unit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Microprocessor controlled circuit breaker trip unit will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-1339988