US3851231A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Short stator induction motor
Assignee: Tracked Hovercraft Ltd
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Filing: 1973-06-19
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Granted: 1974-11-26
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Expires: 1993-06-19
Abstract
Abstract In a short stator electric induction machine, provision is made for reducing the generation of circulating currents when windings are connected in parallel. The coils from which the windings are formed are grouped in sets, the number of coils of each set being equal to the number of branches of the parallel circuit. The coils of each set are located close to one another. One coil from set pair is connected in each branch of the parallel circuit so that each branch comprises coils spaced along the entire length of the stator.
Inventors
- 👤 J Eastham
- 👤 C English
- 👤 G Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:42
CPC Classifications
H; H02; H02K; H02K41/00; H02K41/02; H02K41/025
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
151 words
A stator for a plural phase alternating current short stator electric induction machine, comprising a plurality of sets of coils, each set containing the same number of coils and all coils of each set being disposed closely adjacent to one another and so connected as to provide poles of the same polarity, a plurality of phase bands for each phase, each phase band comprising at least one coil, a series of groups of windings successively displaced along the length of the stator, each group comprising the same number of phase bands for each phase as the number of coils in each set, a plurality of circuit branches for each phase equal in number to the number of coils in each set, each circuit branch containing one phase band from each group of windings, and a parallel circuit for each pHase formed by connecting said circuit branches in parallel one with another.
Claim 2
Dependent Claim
151 words
A stator for a plural phase alternating current short stator electric induction machine, comprising a plurality of sets of coils, each set containing the same number of coils and all coils of each set being disposed closely adjacent to one another and so connected as to provide poles of the same polarity, a plurality of phase bands for each phase, each phase band comprising at least one coil, a series of groups of windings successively displaced along the length of the stator, each group comprising the same number of phase bands for each phase as the number of coils in each set, a plurality of circuit branches for each phase equal in number to the number of coils in each set, each circuit branch containing one phase band from each group of windings, and a parallel circuit for each pHase formed by connecting said circuit branches in parallel one with another.
Claim 3
Dependent Claim
17 words
A stator as claimed in claim 1, in which each set of coils consists of two coils.
Claim 4
Dependent Claim
60 words
A stator as claimed in claim 2, having two groups of windings, in which each branch of each parallel circuit has an intermediate connection point at the junction between the phase bands of the two groups of windings in the branch, whereby the direction of current flow is reversed in the phase bands of one of the groups of windings.
Claim 5
Dependent Claim
61 words
A stator as claimed in claim 3, including switching means adapted, in a first state, to connect the ends of the two branches of each parallel circuit between successive phases of the plural phase supply and, in a second state, to connect the intermediate points of each parallel circuit between a respective phase of the supply and a common neutral point.
Claim 6
Dependent Claim
46 words
A stator as claimed in claim 2, in which each of the groups of windings is divided into a plurality of sub-groups, the sub-groups of each group of windings being interleaved with the sub-groups of the other groups of windings along the length of the stator.
Claim 7
Dependent Claim
98 words
A stator as claimed in claim 5, including switching means operative in a first state to connect each parallel circuit to the supply in such a manner that the instantaneous current in corresponding coils of the two groups is in the same direction and operative in a second state to connect each parallel circuit to the supply in such a manner that the instantaneous current in the coils of one group of windings is in the opposite direction to that of corresponding coils in the other group of windings, whereby the pole number of the machine is changed.
Claim 8
Dependent Claim
33 words
A stator as claimed in claim 1, in which the stator includes a core having slots for receiving the windings, the coils of each set of coils being accommodated in the same slot.
Claim 9
Dependent Claim
31 words
A stator as claimed in claim 1, in which the stator includes a core having slots for receiving windings, the coils of each set of coils being accommodated in adjacent slots.
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) | 1977-11-25 | 1978-05-27 | 1978-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-25 | 1982-05-27 | 1982-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-25 | 1986-05-27 | 1986-11-26 | $7700.00 | Window Closed / Lapsed |