US3775675A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for indicating when current exceeds a predetermined level and when said level is exceeded for a predetermined period of time
Assignee: ABB Inc USA
•
Filing: 1972-06-15
•
Granted: 1973-11-27
•
Expires: 1992-06-15
Abstract
Abstract Transformer fault current monitor which provides recorded indications of the number of times any fault currents have occurred and also of the number of times fault currents which have a duration of more than a predetermined length of time have occurred. Current transformers coupled to the monitored current provide output voltages which are rectified and peak detected. The peak detected voltages are applied to first and second counting means. The first counting means is activated when the monitored current exceeds a predetermined level. The second counting means is activated when the monitored current exceeds a predetermined level for a predetermined length of time.
Inventors
- 👤 J Freeze
- 👤 E Price
- 👤 G Wilburn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:52
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/40; H01F27/402; G; G01; G01R; G01R19/00; G01R19/165; G01R19/16566; G01R19/16585
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
114 words
A current monitor comprising sensing means responsive to a monitored current, said sensing means providing a first voltage which is proportional to the monitored current, peak detecting means connected to said sensing means, said peak detecting means providing a second voltage which is proportional to the peak of the first voltage, first counting means connected to said peak detecting means, said first counting means providing an indication of the number of times the second voltage exceeds a predetermined magnitude, and second counting means connected to said peak detecting means, said second counting means providing an indication of the number of times the second voltage exceeds the predetermined magnitude for a predetermined length of time.
Claim 2
Dependent Claim
114 words
A current monitor comprising sensing means responsive to a monitored current, said sensing means providing a first voltage which is proportional to the monitored current, peak detecting means connected to said sensing means, said peak detecting means providing a second voltage which is proportional to the peak of the first voltage, first counting means connected to said peak detecting means, said first counting means providing an indication of the number of times the second voltage exceeds a predetermined magnitude, and second counting means connected to said peak detecting means, said second counting means providing an indication of the number of times the second voltage exceeds the predetermined magnitude for a predetermined length of time.
Claim 3
Dependent Claim
27 words
The current monitor of claim 1 wherein the sensing means comprises electrical inductive apparatus having an output winding, the first voltage being developed across said output winding.
Claim 4
Dependent Claim
21 words
The current monitor of claim 2 wherein the electrical inductive apparatus includes an input winding through which the monitored current flows.
Claim 5
Dependent Claim
52 words
The current monitor of claim 1 wherein the peak detecting means comprises rectification means and energy storing means, said rectification means providing a rectified voltage across said energy storing means, the energy storing means maintaining a voltage thereon having a magnitude which is substantially equal to the peak of the rectified voltage.
Claim 6
Dependent Claim
63 words
The current monitor of claim 1 wherein the first counting means comprises an electromechanical indicating means which provides an additional indication each time the electromechanical indicating means is energized, said electromechanical indicating means being energized by first switching means, the second voltage being applied to saiD first switching means, and said first switching means conducting when the second voltage exceeds the predetermined magnitude.
Claim 7
Dependent Claim
69 words
The current monitor of claim 1 wherein the second counting means comprises an electromechanical indicating means which provides an additional indication each time the electromechanical indicating means is energized, said electromechanical indicating means being energized by second switching means, the second voltage being applied to said second switching means, and said second switching means conducting when the second voltage exceeds the predetermined magnitude for the predetermined length of time.
Claim 8
Dependent Claim
72 words
The current monitor of claim 6 wherein the second switching means comprises energy storing means which is electrically connected to the second voltage through an impedance means, said energy storing means developing a third voltage thereon when the second voltage exceeds the predetermined magnitude for the predetermined length of time, said third voltage being applied to a solid state circuit element, said circuit element conducting when the third voltage is applied thereto.
Claim 9
Dependent Claim
159 words
A current monitor comprising a current transformer, said current transformer providing a first voltage which is proportional to the current being monitored, full-wave rectification means having input and output terminals, the first voltage being applied to said input terminals, a first capacitor connected across said output terminals, said capacitor having sufficient capacitance to provide a second voltage thereon which is substantially equal to the peak of the voltage developed at the output terminals of said rectification means, first and second counting means, the second voltage being applied to said first counting means which provides an indication of the number of times the second voltage exceeds a predetermined magnitude, the second voltage being applied to a serial combination of a resistor and a second capacitor, the voltage across said second capacitor being applied to said second counting means which provides an indication of the number of times the second voltage exceeds the predetermined magnitude for a predetermined length of time.
Claim 10
Dependent Claim
159 words
A current monitor comprising a current transformer, said current transformer providing a first voltage which is proportional to the current being monitored, full-wave rectification means having input and output terminals, the first voltage being applied to said input terminals, a first capacitor connected across said output terminals, said capacitor having sufficient capacitance to provide a second voltage thereon which is substantially equal to the peak of the voltage developed at the output terminals of said rectification means, first and second counting means, the second voltage being applied to said first counting means which provides an indication of the number of times the second voltage exceeds a predetermined magnitude, the second voltage being applied to a serial combination of a resistor and a second capacitor, the voltage across said second capacitor being applied to said second counting means which provides an indication of the number of times the second voltage exceeds the predetermined magnitude for a predetermined length of time.
References Cited (Backward Citations)
US2114865A
Cited
US3029423A
Cited
US3217246A
Cited
GB1066472A
Cited
US3536994A
Cited
US3573614A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-26 | 1977-05-28 | 1977-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-26 | 1981-05-28 | 1981-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-26 | 1985-05-28 | 1985-11-27 | $7700.00 | Window Closed / Lapsed |