EP0258090B1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Static tripping device for a circuit breaker with electronic contact wear indication
Assignee: Merlin Gerin SA
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Filing: 1987-07-20
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Granted: 1992-03-25
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Expires: 2007-07-20
Abstract
Abstract A digital solid-state trip unit of an electrical circuit breaker is equipped with an electrical contact wear indicator enabling the degree of wear of these contacts to be known. Each time the circuit breaker performs a break, the microprocessor determines a contact wear value, in terms of the maximum value of the current broken. The correspondence between the wear value and the current broken is stored in a ROM memory and the successive wear values are added in a NOVRAM memory whose contents are representative of the degree of contact wear. These contents can be displayed to indicate to the user that the condition of the contacts has to be checked.
Inventors
- 👤 Luc Weynachter
- 👤 Vincent Corcoles
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 20:44
CPC Classifications
H; H01; H01H; H01H1/00; H01H1/0015
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
255 words
A trip unit for an electrical circuit breaker with separable contacts comprising: - a detection circuit (18, 20) generating an analog signal proportional to the current flowing in the conductor protected by the circuit breaker, - an analog-to-digital converter (30) having an input receiving said analog signal and an output delivering a corresponding sampled digitized signal, - a digital processing unit, to which the digitized signal is applied, the digital processing unit comprising a detector means of the value of the current broken each time the circuit breaker performs a break, a device generating, at each break order, a wear value in terms of said current value and representative of the contact wear, due to breaking of said current, and a device for summing and storing said wear values in a memory (40) providing an indicator of the degree of wear of said contacts, trip unit, characterized in that the digital processing unit comprises a microprocessor (32) and performs a long delay tripping function (LR) and/or a short delay tripping function (CR) generating a circuit breaker tripping order, when preset thresholds are exceeded, said order being time delayed according to the value of the signal, and a circuit breaker tripping means (12, 14) being actuated by said tripping order, the value of the broken current being the maximum value obtained by comparison, by the microprocessor (32), between the successive values of said digitized signal which are applied to it between the time the circuit breaker tripping order is generated and effective opening of the contacts.
Claim 2
Dependent Claim
255 words
A trip unit for an electrical circuit breaker with separable contacts comprising: - a detection circuit (18, 20) generating an analog signal proportional to the current flowing in the conductor protected by the circuit breaker, - an analog-to-digital converter (30) having an input receiving said analog signal and an output delivering a corresponding sampled digitized signal, - a digital processing unit, to which the digitized signal is applied, the digital processing unit comprising a detector means of the value of the current broken each time the circuit breaker performs a break, a device generating, at each break order, a wear value in terms of said current value and representative of the contact wear, due to breaking of said current, and a device for summing and storing said wear values in a memory (40) providing an indicator of the degree of wear of said contacts, trip unit, characterized in that the digital processing unit comprises a microprocessor (32) and performs a long delay tripping function (LR) and/or a short delay tripping function (CR) generating a circuit breaker tripping order, when preset thresholds are exceeded, said order being time delayed according to the value of the signal, and a circuit breaker tripping means (12, 14) being actuated by said tripping order, the value of the broken current being the maximum value obtained by comparison, by the microprocessor (32), between the successive values of said digitized signal which are applied to it between the time the circuit breaker tripping order is generated and effective opening of the contacts.
Claim 3
Dependent Claim
47 words
The trip unit according to claim 1, characterized in that the maximum value of the current broken is obtained by comparison of the successive values of the digitized signal during a predetermined duration, corresponding to the maximum duration of the break, after generation of the tripping order.
Claim 4
Dependent Claim
37 words
The solid-state trip unit according to one of the claims 1 and 2, characterized in that the curve representative of the wear value in terms of the maximum value of the current broken is a stepped curve.
Claim 5
Dependent Claim
51 words
The solid-state trip unit according to one of claims 1 to 3, characterized in that said generation devices of summing and storage are included in said microprocessor (32) which comprises a non-volatile NOVRAM memory (40) which is incremented by said corresponding wear value each time the circuit breaker performs a break.
Claim 6
Dependent Claim
55 words
The solid-state trip unit according to anyone of the preceding claims, characterized in that it comprises a circuit breaker (10) contact opening detector (16) which, in the case of manual breaking of the circuit breaker, causes a microprocessor (32) interruption during which the corresponding wear value is generated and added in said NOVRAM memory (40).
Claim 7
Dependent Claim
38 words
The solid-state trip unit according to one of claims 4 and 5, characterized in that it comprises a request command (44) of said microprocessor (32) to request and display the wear value stored in said NOVRAM memory (40).
Claim 8
Dependent Claim
33 words
The solid-state trip unit according to anyone of the preceding claims, characterized in that it comprises an indication and/or alarm device which becomes active when the wear value stored exceeds a preset threshold.
Claim 9
Dependent Claim
26 words
The solid-state trip unit according to claim 7, characterized in that said indication device is arranged so as to cause tripping of the circuit breaker (10).
References Cited (Backward Citations)
No citation records indexed.
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