US5155404A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Squirrel-cage induction motor with rotor slot magnetic bridges
Assignee: ABB AB
•
Filing: 1989-10-02
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Granted: 1992-10-13
•
Expires: 2009-10-02
Abstract
Abstract A squirrel-cage induction motor for frequency converter operation includes a rotor which has a rotor core with a plurality of substantially axially extending rotor slots in which rotor conductors are arranged, each rotor slot having a main portion in which a rotor conductor is arranged and a slot opening arranged between the main portion and that surface of the rotor facing the air gap of the motor, and a magnetic bridge arranged to separate the slot opening from the main portion of the slot, wherein the ends of the magnetic bridge adjoin the rest of the rotor core on either side of the slot opening, and the portion of the bridge opposite to the ends extends into the main portion of the slot.
Inventors
- 👤 Chandur Sadarangani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:17
CPC Classifications
H; H02; H02K; H02K17/00; H02K17/02; H02K17/16
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
122 words
A squirrel-cage induction motor for frequency convertor operation comprising a rotor having a rotor core with a plurality of substantially axially extending rotor slots, each rotor slot having a main portion in which a rotor conductor is arranged and a slot opening arranged between the main portion and that surface of the rotor which faces the air gap of the motor, and a structurally unified magnetic bridge arranged to completely separate the slot opening from the main portion of the slot, wherein ends of the magnetic bridge adjoin the rest of the rotor core on either side of the slot opening, and wherein the portion of the magnetic bridge opposite to the sheet openings extends into said main portion of the slot.
Claim 2
Dependent Claim
122 words
A squirrel-cage induction motor for frequency convertor operation comprising a rotor having a rotor core with a plurality of substantially axially extending rotor slots, each rotor slot having a main portion in which a rotor conductor is arranged and a slot opening arranged between the main portion and that surface of the rotor which faces the air gap of the motor, and a structurally unified magnetic bridge arranged to completely separate the slot opening from the main portion of the slot, wherein ends of the magnetic bridge adjoin the rest of the rotor core on either side of the slot opening, and wherein the portion of the magnetic bridge opposite to the sheet openings extends into said main portion of the slot.
Claim 3
Dependent Claim
30 words
A squirrel-cage induction motor according to claim 1, wherein the width of the bridge is smaller at the central part of the bridge than at the ends of the bridge.
Claim 4
Dependent Claim
23 words
A squirrel-cage induction motor according to claim 2, wherein the width of the bridge decreases continuously from the ends towards the central part.
Claim 5
Dependent Claim
28 words
A squirrel-cage induction motor according to claim 1, wherein the ratio between the height of the bridge and the width of the slot opening is greater than 1.
Claim 6
Dependent Claim
31 words
A squirrel-cage induction motor according to claim 1, wherein the bridge is provided with a recess which forms an extension of the slot opening towards the interior of the rotor conductor.
Claim 7
Dependent Claim
26 words
A squirrel-cage induction motor according to claim 5, wherein the width of the recess decreases from the slot opening in a direction towards the rotor conductor.
Claim 8
Dependent Claim
27 words
A squirrel-cage induction motor according to claim 6, wherein the width of the recess decreases continuously from the slot opening in a direction towards the rotor conductor.
Claim 9
Dependent Claim
35 words
A squirrel-cage induction motor according to claim 5, wherein the bridge is U- or V-shaped with two branches, arranged on each side of the center of the bridge, said branches forming between them said recess.
Claim 10
Dependent Claim
19 words
A squirrel-cage induction motor according to any of claim 1 wherein the slot opening is free from conducting materials.
Claim 11
Dependent Claim
28 words
A squirrel-cage induction motor according to claim 3, wherein the ratio between the height of the bridge and the width of the slot opening is greater than 1.
Claim 12
Dependent Claim
31 words
A squirrel-cage induction motor according to claim 4, wherein the bridge is provided with a recess which forms an extension of the slot opening towards the interior of the rotor conductor.
Claim 13
Dependent Claim
35 words
A squirrel-cage induction motor according to claim 6, wherein the bridge is U- or V-shaped with two branches arranged on each side of the center of the bridge, said branches forming between them said recess.
Claim 14
Dependent Claim
35 words
A squirrel-cage induction motor according to claim 7, wherein the bridge is U- or V-shaped with two branches arranged on each side of the center of the bridge, said branches forming between them said recess.
Claim 15
Dependent Claim
129 words
A squirrel-cage induction motor for frequency convertor operation comprising a rotor having a rotor core with a plurality of substantially axially extending rotor slots, each rotor slot having a main portion in which a rotor conductor is arranged and a slot opening arranged between the main portion and that surface of the rotor which faces the air gap of the motor, and a magnetic bridge arranged to separate the slot opening from the main portion of the slot, wherein ends of the magnetic bridge adjoin the rest of the rotor core on either side of the slot opening, and wherein said magnetic bridge has an inner surface, which faces the rotor conductor that is U- or V-shaped with its vertex protruding towards the rotor conductor in said main portion.
Claim 16
Dependent Claim
129 words
A squirrel-cage induction motor for frequency convertor operation comprising a rotor having a rotor core with a plurality of substantially axially extending rotor slots, each rotor slot having a main portion in which a rotor conductor is arranged and a slot opening arranged between the main portion and that surface of the rotor which faces the air gap of the motor, and a magnetic bridge arranged to separate the slot opening from the main portion of the slot, wherein ends of the magnetic bridge adjoin the rest of the rotor core on either side of the slot opening, and wherein said magnetic bridge has an inner surface, which faces the rotor conductor that is U- or V-shaped with its vertex protruding towards the rotor conductor in said main portion.
Claim 17
Dependent Claim
17 words
A squirrel-cage induction motor according to claim 14, wherein the slot opening is free from conducting materials.
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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) | 1995-10-13 | 1996-04-13 | 1996-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-13 | 2000-04-13 | 2000-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-13 | 2004-04-13 | 2004-10-13 | $7700.00 | Window Closed / Lapsed |