US4771355A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System and method for arc detection in dynamoelectric machines
Assignee: Electric Power Research Institute
•
Filing: 1986-12-29
•
Granted: 1988-09-13
•
Expires: 2006-12-29
Abstract
Abstract System and method of detecting arcing faults in dynamoelectric machines by monitoring the voltage on the neutral grounding lead to detect RF voltages produced by arcing in the machine. The voltage is monitored by an RF voltage coupler and an RF monitor having a high impedance input amplifier. In one embodiment, the voltage coupler is clamped onto the neutral lead, and in another it is connected electrically in series with it.
Inventors
- 👤 Franklin T. Emery
- 👤 Ronald T. Harrold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:40
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/34; G01R31/343; H; H02; H02H; H02H1/00; H02H1/0007; H02H1/0015; G01R31/12; G01R31/1227
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
75 words
In a system for detecting an arcing fault in a dynamoelectric machine operating at a relatively low power line frequency and having a neutral grounding lead: a radio frequency voltage coupler coupled to the neutral lead for passing high frequency signals and blocking voltages at the power line frequency, and a radio frequency monitor connected to the voltage coupler for detecting a radio frequency voltage produced in the neutral lead by arcing in the machine.
Claim 2
Dependent Claim
75 words
In a system for detecting an arcing fault in a dynamoelectric machine operating at a relatively low power line frequency and having a neutral grounding lead: a radio frequency voltage coupler coupled to the neutral lead for passing high frequency signals and blocking voltages at the power line frequency, and a radio frequency monitor connected to the voltage coupler for detecting a radio frequency voltage produced in the neutral lead by arcing in the machine.
Claim 3
Dependent Claim
16 words
The system of claim 1 wherein the voltage coupler is capacitively coupled to the neutral lead.
Claim 4
Dependent Claim
46 words
The system of claim 2 wherein the voltage coupler comprises a generally cylindrical electrically conductive plate disposed coaxially of the neutral lead, with the neutral lead and the generally cylindrical plate forming a coaxial capacitor, the radio frequency monitor being connected to the generally cylindrical plate.
Claim 5
Dependent Claim
16 words
The system of claim 3 wherein the generally cylindrical plate is clamped about the neutral lead.
Claim 6
Dependent Claim
29 words
The system of claim 3 wherein the voltage coupler includes a central conductor connected electrically in series with the neutral lead and positioned coaxially within the generally cylindrical plate.
Claim 7
Dependent Claim
21 words
The system of claim 1 wherein the radio frequency monitor comprises a radio frequency voltage amplifier having a high input impedance.
Claim 8
Dependent Claim
20 words
The system of claim 1 wherein the voltage coupler is connected to the radio frequency monitor by a coaxial cable.
Claim 9
Dependent Claim
38 words
In a method of detecting an arcing fault in a dynamoelectric machine having neutral grounding lead: monitoring the neutral lead with a radio frequency voltage monitor to detect a radio frequency voltage produced by arcing in the machine.
Claim 10
Dependent Claim
38 words
In a method of detecting an arcing fault in a dynamoelectric machine having neutral grounding lead: monitoring the neutral lead with a radio frequency voltage monitor to detect a radio frequency voltage produced by arcing in the machine.
References Cited (Backward Citations)
US3396339A
Cited
GB1058890A
Cited
US3882379A
Cited
US4052665A
Cited
US4156846A
Cited
US4224652A
Cited
US4149208A
Cited
SU670995A1
Cited
US4286238A
Cited
US4363061A
Cited
US4356443A
Cited
US4446426A
Cited
US4638396A
Cited
US4636708A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-13 | 1992-03-14 | 1992-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-13 | 1996-03-14 | 1996-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-13 | 2000-03-14 | 2000-09-13 | $7700.00 | Window Closed / Lapsed |