US4097754A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Short pitch alternator
Assignee: Tecumseh Products Co
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Filing: 1976-10-20
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Granted: 1978-06-27
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Expires: 1996-10-20
Abstract
Abstract A three-phase permanent magnet alternator is disclosed employing a fractional pitch stator winding of about two-thirds or 120 electrical degrees for minimizing third harmonic circulating current in the phase windings. The alternator has a rotor supporting permanent magnet poles and a slotted stator having coils disposed in the slots with the pitch of each coil being less than the rotor pole pitch and the coils of each phase connected in series to form a fractional pitch phase winding. The rotor circumscribes the stator and the permanent magnet poles have an arcuate extent nearly as great as the rotor pole pitch.
Inventors
- 👤 James B. Farr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:53
CPC Classifications
H; H02; H02K; H02K3/00; H02K3/04; H02K3/28; H02K21/00; H02K21/12; H02K21/22; H02K21/222
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
77 words
A three-phase alternating current generator having first and second relatively rotatable portions, an even number of n magnetic poles disposed on the first portion, the second portion comprising a slotted magnetic core having 3n slots respectively defining teeth therebetween, 3n coils, each coil being disposed about an adjacent pair of teeth and every third coil being connected in series to form a phase winding, there being three-phase windings each formed of a different group of n coils.
Claim 2
Dependent Claim
77 words
A three-phase alternating current generator having first and second relatively rotatable portions, an even number of n magnetic poles disposed on the first portion, the second portion comprising a slotted magnetic core having 3n slots respectively defining teeth therebetween, 3n coils, each coil being disposed about an adjacent pair of teeth and every third coil being connected in series to form a phase winding, there being three-phase windings each formed of a different group of n coils.
Claim 3
Dependent Claim
22 words
The generator of claim 1 wherein said poles are permanent magnets, the second portion being stationary and comprising an annular laminated member.
Claim 4
Dependent Claim
18 words
The generator of claim 2 wherein the first portion is concentric with and rotatable about the second portion.
Claim 5
Dependent Claim
9 words
The generator of claim 1 wherein n = 8.
Claim 6
Dependent Claim
22 words
The generator of claim 1 wherein the coil pitch is about 120 electrical degrees thereby minimizing third harmonic current in the windings.
Claim 7
Dependent Claim
28 words
The generator of claim 1 wherein the rotor circumscribes the stator with the permanent magnet poles having an arcuate extent nearly as great as the rotor pole pitch.
Claim 8
Dependent Claim
31 words
The generator of claim 1 wherein each permanent magnet pole has a pitch which is greater than the pitch of each coil and which is less than the rotor pole pitch.
Claim 9
Dependent Claim
15 words
The generator of claim 1 wherein the three-phase windings are connected together in delta configuration.
Claim 10
Dependent Claim
16 words
The generator of claim 1 wherein the three-phase windings are connected together in a wye configuration.
Claim 11
Dependent Claim
170 words
An alternating current generator having a rotor supporting an even number of permanent magnet poles defining a given pole pitch, and a slotted stator having coils disposed in the slots thereof, the pitch of each coil being less than the rotor pole pitch, every third coil being connected in series to form a fractional pitch phase winding, there being three phase windings connected together in a configuration to form a three-phase generator, and wherein there are n magnetic poles disposed about the rotor, 3n slots substantially uniformly disposed about the stator and 3n coils, each coil having one side disposed in a specified slot and its other side disposed in a slot spaced from the specified slot by one slot, alternate slots having one side of a coil of a first phase and one side of a coil of a second phase therein, the slots intermediate said alternature slots having one side of a coil of said second phase and one side of a coil of the third phase therein.
Claim 12
Dependent Claim
170 words
An alternating current generator having a rotor supporting an even number of permanent magnet poles defining a given pole pitch, and a slotted stator having coils disposed in the slots thereof, the pitch of each coil being less than the rotor pole pitch, every third coil being connected in series to form a fractional pitch phase winding, there being three phase windings connected together in a configuration to form a three-phase generator, and wherein there are n magnetic poles disposed about the rotor, 3n slots substantially uniformly disposed about the stator and 3n coils, each coil having one side disposed in a specified slot and its other side disposed in a slot spaced from the specified slot by one slot, alternate slots having one side of a coil of a first phase and one side of a coil of a second phase therein, the slots intermediate said alternature slots having one side of a coil of said second phase and one side of a coil of the third phase therein.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-06-26 | 1981-12-26 | 1982-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-26 | 1985-12-26 | 1986-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-26 | 1989-12-26 | 1990-06-27 | $7700.00 | Window Closed / Lapsed |