Patent US4285919A successfully refreshed from Google Patents.
Patent US4819124A successfully refreshed from Google Patents.
US4819124A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Overcurrent detector and circuit breaker
Assignee: Mitsubishi Electric Corp
•
Filing: 1987-07-24
•
Granted: 1989-04-04
•
Expires: 2007-07-24
Abstract
Abstract A solid state overcurrent detector is provided with a current sensor means (200) having an OR circuit (130) connected by its input terminals to output terminals of burden circuits (41,42,43). A phase selecting circuit (400) for selecting the largest phase is connected by its input terminals to the output terminals of the burden circuits. The output terminal of the phase selecting circuit (400) is connected through a signal converting circuit (90) and an A/D converter (100) to a microcomputer (110) having a first level-discrimination circuit (1001) and a first time-current operation circuit (1002) with inverse time-current characteristics for various time interruptions responding to an amount of overcurrent. The output terminals of the OR circuit (130) are connected through a second level-discrimination circuit (140) to a second time-current operation circuit (150) for instant interruption.
Inventors
- 👤 Ichirou Arinobu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:21
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/08; H02H3/093; H02H3/0935
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
120 words
An overcurrent detector comprising: current sensor means provided for respective phases of AC power lines for detecting a current value; phase selecting means for selectively outputting one phase signal having a largest waveform from among three phase signals inputted thereto from said current sensor means by outputting at least one half cycle of said one phase signal. peak value detection means for detecting a largest instantaneous value from instantaneous values of said sensing outputs; signal converison means for obtaining a mean square (Im 2 ) of output of said phase selecting means; and processing means for processing an output signal of said signal conversion means and an output signal of said peak value detection means to issue a releasing signal.
Claim 2
Dependent Claim
120 words
An overcurrent detector comprising: current sensor means provided for respective phases of AC power lines for detecting a current value; phase selecting means for selectively outputting one phase signal having a largest waveform from among three phase signals inputted thereto from said current sensor means by outputting at least one half cycle of said one phase signal. peak value detection means for detecting a largest instantaneous value from instantaneous values of said sensing outputs; signal converison means for obtaining a mean square (Im 2 ) of output of said phase selecting means; and processing means for processing an output signal of said signal conversion means and an output signal of said peak value detection means to issue a releasing signal.
Claim 3
Dependent Claim
135 words
An overcurrent detector in accordance with claim 1, wherein said processing means includes a microcomputer for processing said output signal of the signal conversion means and comprises: first level-discrimination means for discriminating levels of output signal of said phase selecting means, first time-current operating means for performing a first time-current operation when said output signal from phase selecting means is discriminated to be above a level discriminated by said first level-discrimination means, second level-discrimination means for discriminating levels of output signal of said peak value detection means, second time-current operating means for performing a second time-current operation when said peak value is discriminated whether it is above a level discriminated by said second-level discrimination means, and output means for issuing the releasing signal in accordance with operations of said first and second time-current operating means.
Claim 4
Dependent Claim
163 words
An overcurrent detector in accordance with claim 1, wherein said processing means includes a microcomputer for processing said output signal of the signal conversion means and comprises: first level-discrimination means for discriminating levels of output signal of said phase selecting means, first time-current operating means for performing a first time-current operation when said output signal from phase selecting means is discriminated whether it is above a level discriminated by said first level-discrimination means, second level-discrimination means for discriminating levels of output signal of said peak value detection means, second time-current operating means for performing a second time-current operation when said peak value is discriminated whether it is above a level discriminated by said second-level discrimination means, current conversion means for converting output of said signal conversion means into current value, and third time-current operating means for performing a third time-current operation when said output signal from signal converison means is discriminated whether it is above a level discriminated by said current conversion means.
Claim 5
Dependent Claim
35 words
An overcurrent detector in accordance with claim 2, wherein said second level discrimination means takes as a theshold value the difference between a microcomputer controlled D/A converted output from said microcomputer and a predetermined value.
Claim 6
Dependent Claim
134 words
A circuit breaker comprising: a disconnectable contact provided in an A.C. power line, current sensor means provided for respective phases of AC power lines for detecting a value of current, phase selecting means for selectively outputting one phase signal having a largest waveform from among three phase signals inputted thereto from said current sensor means outputting at least one half cycle of said one phase signal, peak value detection means for detecting a largest instantaneous value from instantaneous values of said sensing outputs, signal conversion means for obtaining a mean square (Im 2 ) of output of said phase selecting means, processing means which processes an output signal of said signal conversion means to issue a releasing signal, and releasing means for inducing disconnection of said disconnectable contact in response to said releasing signal.
Claim 7
Dependent Claim
134 words
A circuit breaker comprising: a disconnectable contact provided in an A.C. power line, current sensor means provided for respective phases of AC power lines for detecting a value of current, phase selecting means for selectively outputting one phase signal having a largest waveform from among three phase signals inputted thereto from said current sensor means outputting at least one half cycle of said one phase signal, peak value detection means for detecting a largest instantaneous value from instantaneous values of said sensing outputs, signal conversion means for obtaining a mean square (Im 2 ) of output of said phase selecting means, processing means which processes an output signal of said signal conversion means to issue a releasing signal, and releasing means for inducing disconnection of said disconnectable contact in response to said releasing signal.
Claim 8
Dependent Claim
126 words
A circuit breaker in accordance with claim 5, wherein said processing means includes a microcomputer and comprises: first level-discrimination means for discriminating levels of output signal of said phase selecting means, first time-current operating means for performing a first time-current operation when said output signal from the phase selecting means is discriminated to be above a level discriminated by said first level-discrimination means, second level-discrimination means for discriminating levels of output signal of said peak value detection means, second time-current operating means for performing a second time-current operation when said peak value is discriminated whether it is above a level discriminated by said second-level discrimination means, output means and for issuing the releasing signal in accordance with operations of said first and second time-current operating means.
Claim 9
Dependent Claim
156 words
A circuit breaker in accordance with claim 5, wherein said processing means includes a microcomputer and comprises: first level discrimination means for discriminating levels of output signal of said phase selecting means, first time-current operating means for performing a first time-current operation when said output signal from phase selecting means is discriminated whether it is above a level discriminated by said first level discrimination means, second level-discrimination means for discriminating levels of output signal of said peak value detection means, second time-current operating means for performing a second time-current operation when said peak value is discriminated whether it is above a level discriminated by said second level discrimination means, current conversion means for converting output of said signal conversion means into current value, and third time-current operation means for performing a third time-current operation when said output signal from signal conversion means is discriminated whether it is above a level discriminated by said current conversion means.
Claim 10
Dependent Claim
35 words
A circuit breaker in accordance with claim 6, wherein said second level discrimination means takes as a threshold value a difference between said microcomputer controlled D/A converted output from said microcomputer and a predetermined value.
References Cited (Backward Citations)
US3846675A
Cited
US4246623A
Cited
DE3114213A1
Cited
US4429340A
Cited
JPS6032211A
Cited
EP0133968A1
Cited
US4550360A
Cited
US4672501A
Cited
US4589052A
Cited
US4685024A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-04-03 | 1992-10-03 | 1993-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-03 | 1996-10-03 | 1997-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-03 | 2000-10-03 | 2001-04-04 | $7700.00 | Window Closed / Lapsed |