US3619748A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Two-speed, single-phase electric motors
Assignee: NAT RES DEV
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Filing: 1969-09-24
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Granted: 1971-11-09
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Expires: 1989-09-24
Abstract
Abstract A close ratio, two-speed, pole-changing single-phase electric motor having a stator winding tapped and connected for polechanging by the so-called phase-mixing or step-phase modulation technique and including means for providing starting torque comprising, preferably, shading rings or gap variation at every pole.
Inventors
- 👤 John F Eastham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:49
CPC Classifications
H; H02; H02K; H02K17/00; H02K17/02; H02K17/04; H02K17/06; H02K17/10
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
104 words
A single-phase alternating current, pole-changing electric motor having alternative pole numbers in close ratio comprising a stator including a diametrically symmetrical slot arrangement providing a plurality of pole faces of unequal length for each half circumference, a stator winding comprising a plurality of coils arranged as two groups each group extending around a half circumference of the stator, said plurality of coils being equal to said plurality of pole faces, means for connecting said coil groups together, means for reversing the current-carrying sense of one of said coil groups so as to provide said alternative pole numbers, and means for providing a starting torque.
Claim 2
Dependent Claim
104 words
A single-phase alternating current, pole-changing electric motor having alternative pole numbers in close ratio comprising a stator including a diametrically symmetrical slot arrangement providing a plurality of pole faces of unequal length for each half circumference, a stator winding comprising a plurality of coils arranged as two groups each group extending around a half circumference of the stator, said plurality of coils being equal to said plurality of pole faces, means for connecting said coil groups together, means for reversing the current-carrying sense of one of said coil groups so as to provide said alternative pole numbers, and means for providing a starting torque.
Claim 3
Dependent Claim
18 words
An electric motor as claimed in claim 1 wherein said starting torque providing means comprises shading ring means.
Claim 4
Dependent Claim
19 words
An electric motor as claimed in claim 1 wherein said starting torque providing means comprises variable air gap means.
Claim 5
Dependent Claim
24 words
An electric motor as claimed in claim 1 wherein said starting torque providing means comprises both shading ring means and variable air gap means.
Claim 6
Dependent Claim
19 words
An electric motor as claimed in claim 1 wherein said stator provides alternative pole numbers differing by two poles.
Claim 7
Dependent Claim
23 words
An electric motor as claimed in claim 2 wherein said shading ring means comprises shading rings arranged on every pole of said stator.
Claim 8
Dependent Claim
23 words
An electric motor as claimed in claim 3 wherein said variable airgap means comprises a variable gap on every pole of said stator.
Claim 9
Dependent Claim
33 words
An electric motor as claimed in claim 1 wherein said means for providing a starting torque comprises a gap varying progressively in width from one end of each pole face to the other.
Claim 10
Dependent Claim
34 words
An electric motor as claimed in claim 1 wherein said means for providing a starting torque comprises a gap varying stepwise progressively in width from one end of each pole face to the other.
References Cited (Backward Citations)
US3233160A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-08 | 1975-05-10 | 1975-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-08 | 1979-05-10 | 1979-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-08 | 1983-05-10 | 1983-11-09 | $7700.00 | Window Closed / Lapsed |