Patent US3721844A successfully refreshed from Google Patents.
US3721844A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reluctance motors
Assignee: National Research Development Corp UK
•
Filing: 1971-05-27
•
Granted: 1973-03-20
•
Expires: 1991-05-27
Abstract
Abstract The rotor of a reluctance motor has a squirrel cage winding and flux barriers which follow the paths of direct axis flux between alternate pairs of poles but lie athwart the paths of quadrature axis flux. The number of flux barriers is equal to half the number of poles for which the stator is wound, but there are not less than three flux barriers. The angles subtended at the central axis of the rotor between the ends of each flux barrier and between the ends of adjacent flux barriers are all equal to each other. In addition auxiliary flux barriers may be provided which are embraced by the main flux barriers or extend between the ends of adjacent flux barriers, or both. Also circumferential grooves may be provided either in sectors defined by the end of the main flux barriers or in sectors defined by the ends of adjacent flux barriers, or both.
Inventors
- 👤 W Fong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:55
CPC Classifications
H; H02; H02K; H02K1/00; H02K1/06; H02K1/22; H02K1/24; H02K1/246
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
103 words
A reluctance motor comprising a stator member wound to provide a magnetic field having p pole-pairs and a rotor member of unitary stampings having a short-circuited electrical winding and magnetic material in which there are p flux barriers following the paths of direct axis flux between alternate pairs of poles but lying athwart the paths of quadrature axis flux, where p is a whole number of at least three, wherein circumferential grooves are provided in the periphery of the rotor in the sectors between adjacent main flux barriers and said flux barriers terminate at positions which are within the boundary of the stampings.
Claim 2
Dependent Claim
103 words
A reluctance motor comprising a stator member wound to provide a magnetic field having p pole-pairs and a rotor member of unitary stampings having a short-circuited electrical winding and magnetic material in which there are p flux barriers following the paths of direct axis flux between alternate pairs of poles but lying athwart the paths of quadrature axis flux, where p is a whole number of at least three, wherein circumferential grooves are provided in the periphery of the rotor in the sectors between adjacent main flux barriers and said flux barriers terminate at positions which are within the boundary of the stampings.
Claim 3
Dependent Claim
149 words
A reluctance motor comprising a stator member wound to provide a magnetic field having p pole-pairs and a rotor member of unitary stampings having a short-circuited electrical winding and magnetic material in which there are p, and only p main flux barriers following the paths of direct axis flux between alternate pairs of poles but lying athwart the paths of quadrature axis flux, where p is a whole number of at least three, with circumferential grooves provided in the periphery of the rotor in the sectors between the ends of the main flux barriers, said main flux barriers being symmetrically distributed around the rotor such that the angles at the central axis of the rotor subtended between the ends of each flux barrier and between the ends of adjacent flux barriers is given by pi /p radians and terminating at positions which are within the boundary of said stamping.
Claim 4
Dependent Claim
149 words
A reluctance motor comprising a stator member wound to provide a magnetic field having p pole-pairs and a rotor member of unitary stampings having a short-circuited electrical winding and magnetic material in which there are p, and only p main flux barriers following the paths of direct axis flux between alternate pairs of poles but lying athwart the paths of quadrature axis flux, where p is a whole number of at least three, with circumferential grooves provided in the periphery of the rotor in the sectors between the ends of the main flux barriers, said main flux barriers being symmetrically distributed around the rotor such that the angles at the central axis of the rotor subtended between the ends of each flux barrier and between the ends of adjacent flux barriers is given by pi /p radians and terminating at positions which are within the boundary of said stamping.
Claim 5
Dependent Claim
29 words
The reluctance motor as claimed in claim 2 in which auxiliary flux barriers are provided which extend generally parallel to the main flux barriers and are embraced by them.
Claim 6
Dependent Claim
20 words
The reluctance motor as claimed in claim 3 in which each main flux barrier embraces a single auxiliary flux barrier.
Claim 7
Dependent Claim
21 words
The reluctance motor as claimed in claim 3 in which each main flux barrier embraced at least two auxiliary flux barriers.
Claim 8
Dependent Claim
86 words
A reluctance motor comprising a stator member wound to provide a magnetic field having p pole-pAirs and a rotor member having a short-circuited electrical winding and magnetic material in which there are p flux barriers following the paths of direct axis flux between alternate pairs of poles but lying athwart the paths of quadrature axis flux, where p is a whole number of at least three, and wherein circumferential grooves are provided in the periphery of the rotor in the sectors between adjacent main flux barriers.
Claim 9
Dependent Claim
86 words
A reluctance motor comprising a stator member wound to provide a magnetic field having p pole-pAirs and a rotor member having a short-circuited electrical winding and magnetic material in which there are p flux barriers following the paths of direct axis flux between alternate pairs of poles but lying athwart the paths of quadrature axis flux, where p is a whole number of at least three, and wherein circumferential grooves are provided in the periphery of the rotor in the sectors between adjacent main flux barriers.
Claim 10
Dependent Claim
84 words
A reluctance motor comprising a stator member wound to provide a magnetic field having p pole-pairs and a rotor member having a short-circuited electrical winding and magnetic material in which there are p flux barriers following the paths of direct axis flux between alternate pairs of poles but lying athwart the paths of quadrature axis flux, where p is a whole number of at least three, and wherein auxiliary flux barriers are provided in the sectors between the ends of adjacent main flux barriers.
Claim 11
Dependent Claim
84 words
A reluctance motor comprising a stator member wound to provide a magnetic field having p pole-pairs and a rotor member having a short-circuited electrical winding and magnetic material in which there are p flux barriers following the paths of direct axis flux between alternate pairs of poles but lying athwart the paths of quadrature axis flux, where p is a whole number of at least three, and wherein auxiliary flux barriers are provided in the sectors between the ends of adjacent main flux barriers.
References Cited (Backward Citations)
US2733362A
Cited
US3126493A
Cited
US2913607A
Cited
US2975310A
Cited
US3016482A
Cited
US3210584A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |