US4816756A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit and method for statically testing rotating rectifiers in brushless alternators
Assignee: Sundstrand Corp
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Filing: 1987-09-03
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Granted: 1989-03-28
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Expires: 2007-09-03
Abstract
Abstract Rectifiers mounted on the rotor of a brushless alternator are tested by applying an AC voltage to an exciter field winding of the brushless alternator. This applied voltage induces current in a rotor mounted exciter armature winding which is inductively coupled to the exciter field winding and produces current flow through the rectifiers. The magnitude of an even harmonic component of the exciter field winding current is measured and compared to a predetermined magnitude to obtain an indication of the operational status of at least one of the rectifiers. This comparison may be done manually or may be performed electronically in accordance with known techniques.
Inventors
- 👤 David A. Fox
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:49
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/145; G01R19/15; G01R31/00; G01R31/34; G01R31/26; G01R31/2607; G01R31/2632
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
95 words
A method for testing rectifiers mounted on rotors of brushless alternators comprising the steps of: applying an AC voltage to an exciter field winding of a brushless alternator having a plurality of rectifiers mounted on a rotor, said rectifiers being electrically connected to an exciter armature winding which is inductively coupled to said exciter field winding; measuring the magnitude of an even harmonic component of current in said exciter field winding; and comparing said magnitude to a first predetermined value to obtain an indication of the operational status of at least one of said rectifiers.
Claim 2
Independent Claim
95 words
A method for testing rectifiers mounted on rotors of brushless alternators comprising the steps of: applying an AC voltage to an exciter field winding of a brushless alternator having a plurality of rectifiers mounted on a rotor, said rectifiers being electrically connected to an exciter armature winding which is inductively coupled to said exciter field winding; measuring the magnitude of an even harmonic component of current in said exciter field winding; and comparing said magnitude to a first predetermined value to obtain an indication of the operational status of at least one of said rectifiers.
Claim 3
Dependent Claim
25 words
A method for testing rectifiers mounted on rotors of brushless alternators, as recited in claim 1, wherein: said even harmonic component is the second harmonic.
Claim 4
Dependent Claim
25 words
A method for testing rectifiers mounted on rotors of brushless alternators, as recited in claim 1, wherein: said rotor is stationary during said measuring step.
Claim 5
Dependent Claim
40 words
A method for testing rectifiers mounted on rotors of brushless alternators, as recited in claim 1, wherein the measuring step includes the steps of: producing a signal representative of said current; and filtering said signal to derive said harmonic component.
Claim 6
Dependent Claim
32 words
A method for testing rectifiers mounted on rotors of brushless alternators, as recited in claim 1, wherein: said AC voltage has sufficient magnitude to overcome the forward voltage drop of said rectifiers.
Claim 7
Dependent Claim
72 words
A method for testing rectifiers mounted on rotors of brushless alternators, as recited in claim 1, further comprising the steps of: measuring the total magnitude of said current; wherein said total magnitude of said current is defined as the fundamental plus all harmonic components, and comparing the total magnitude of said current to a second predetermined value to obtain an indication of the operational status of at least one of said rectifiers.
Claim 8
Dependent Claim
101 words
A circuit for testing rectifiers mounted on rotors of brushless alternators comprising: an AC voltage source for applying an AC voltage to an exciter field winding of a brushless alternator having a plurality of rectifiers mounted on a rotor, said rectifiers being electrically connected to an exciter armature winding which is inductively coupled to said exciter field winding; means for measuring the magnitude of an even harmonic component of current in said exciter field winding; and means for comparing said magnitude to a first preselected value to obtain an indication of the operational status of at least one of said rectifiers.
Claim 9
Dependent Claim
101 words
A circuit for testing rectifiers mounted on rotors of brushless alternators comprising: an AC voltage source for applying an AC voltage to an exciter field winding of a brushless alternator having a plurality of rectifiers mounted on a rotor, said rectifiers being electrically connected to an exciter armature winding which is inductively coupled to said exciter field winding; means for measuring the magnitude of an even harmonic component of current in said exciter field winding; and means for comparing said magnitude to a first preselected value to obtain an indication of the operational status of at least one of said rectifiers.
Claim 10
Dependent Claim
25 words
A circuit for testing rectifiers mounted on rotors of brushless alternators, as recited in claim 7, wherein: said even harmonic component is the second harmonic.
Claim 11
Dependent Claim
42 words
A circuit for testing rectifiers mounted on rotors of brushless alternators, as recited in claim 7 wherein said means for measuring includes: means for producing a signal representative of said current; and means for filtering said signal to derive said harmonic component.
Claim 12
Dependent Claim
32 words
A circuit for testing rectifiers mounted on rotors of brushless alternators, as recited in claim 7, wherein: said AC voltage has sufficient magnitude to overcome the forward voltage drop of said rectifiers.
Claim 13
Dependent Claim
73 words
A circuit for testing rectifiers mounted on rotors of brushless alternators, as recited in claim 7, further comprising: means for measuring the total magnitude of said current; wherein said total magnitude of said current is defined as the fundamental plus all harmonic components, and means for comparing the total magnitude of said current to a second predetermined value to obtain an indication of the operational status of at least one of said rectifiers.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-27 | 1992-09-26 | 1993-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-27 | 1996-09-26 | 1997-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-27 | 2000-09-26 | 2001-03-28 | $7700.00 | Window Closed / Lapsed |