Digitally controlled circuit interrupter with improved automatic

Details Digitally controlled circuit interrupter with improved automatic Digitally controlled circuit interrupter with improved automatic

1994-05-26

1996-09-24

Trammell, James P.

Boots, shoes, and leggings

364492, 324520, 324 7611, 361 78, 361 85, 361 87, H02H 326, G01R 1900, H02J 300

Patent

active

055597190

ABSTRACT:
A circuit interrupter with a digital trip unit automatically sets the sampling interval appropriate for the 50 Hz or 60 Hz distribution system to which the interrupter is connected. In order to avoid falsely shifting the interval in response to distorted currents, the trip unit only changes the interval if the number of zero crossings of the current within a fixed number of samples is within two zero crossings of the number of zero crossings for an undistorted current of the other frequency for two consecutive time periods in which the fixed number of samples are taken. Furthermore, changes in the interval are only written into an EEPROM for use on power-up a fixed number of times to preclude disabling the EEPROM. In one embodiment, a 2 pole filter is utilized in the zero crossing counting circuit to eliminate false counts from noise originating in a chopper used in the trip unit power supply. In another embodiment, the zero crossing counting circuit is disabled unless external dc power is available for the trip unit which idles the chopper.

REFERENCES:
patent: 4335437 (1982-06-01), Wilson et al.
patent: 4351012 (1982-09-01), Elms et al.
patent: 4351013 (1982-09-01), Matsko et al.
patent: 4377836 (1983-03-01), Elms et al.
patent: 4428022 (1984-01-01), Engel et al.
patent: 5224054 (1993-06-01), Wallis
patent: 5233538 (1993-08-01), Wallis
patent: 5270898 (1993-12-01), Elms et al.
patent: 5331501 (1994-07-01), Shimp
patent: 5391982 (1995-02-01), Kim
patent: 5428495 (1995-06-01), Murphy et al.

Affiliated with

Also associated with

Rating

Digitally controlled circuit interrupter with improved automatic does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Digitally controlled circuit interrupter with improved automatic, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Digitally controlled circuit interrupter with improved automatic will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1934161