US3720865A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Brushless d.c. motor
Assignee: Thales SA
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Filing: 1972-03-24
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Granted: 1973-03-13
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Expires: 1992-03-24
Abstract
Abstract A brushless D. C. motor has a stator, the windings of which are connected to a D. C. source through the medium of pairs of switches in such a manner that these windings are permanently fed and that the current is reversed in the windings at the moment when no counterelectromotive force is induced therein, this winding being at this moment put in series with at least one other winding in which the counterelectromotive force induced is not zero.
Inventors
- 👤 M Bregeault
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 04:13
CPC Classifications
H; H02; H02P; H02P8/00; H02P8/14; H02K; H02K29/00; H02K29/06; H02K29/08
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
173 words
A brushless D.C. motor comprising a stator having q windings with q>1, a rotor having at least one pair of poles, detector means for detecting said rotor position relative to said stator windings, arranged to determine the instant at which the counterelectromotive force induced by said rotor in at least one of said windings is zero, the occurrence of said instant resulting in a reversement in the direction of the current flowing therein, switching means for operating said current reversement, said switching means being controlled by said detector means and being respectively associated with said windings for so connecting them to a D.C. source that all the windings are fed permanently, that the current flowing in certain windings is smaller than that flowing in other windings and that the winding in which the direction of current is being reversed, is one of these certain windings, the windings in which the counterelectromotive force is zero being at that instant in series with at least one other winding in which this force is not zero.
Claim 2
Dependent Claim
173 words
A brushless D.C. motor comprising a stator having q windings with q>1, a rotor having at least one pair of poles, detector means for detecting said rotor position relative to said stator windings, arranged to determine the instant at which the counterelectromotive force induced by said rotor in at least one of said windings is zero, the occurrence of said instant resulting in a reversement in the direction of the current flowing therein, switching means for operating said current reversement, said switching means being controlled by said detector means and being respectively associated with said windings for so connecting them to a D.C. source that all the windings are fed permanently, that the current flowing in certain windings is smaller than that flowing in other windings and that the winding in which the direction of current is being reversed, is one of these certain windings, the windings in which the counterelectromotive force is zero being at that instant in series with at least one other winding in which this force is not zero.
Claim 3
Dependent Claim
173 words
A brushless D.C. motor comprising a stator having q windings with q>1, a rotor having at least one pair of poles, detector means for detecting said rotor position relative to said stator windings, arranged to determine the instant at which the counterelectromotive force induced by said rotor in at least one of said windings is zero, the occurrence of said instant resulting in a reversement in the direction of the current flowing therein, switching means for operating said current reversement, said switching means being controlled by said detector means and being respectively associated with said windings for so connecting them to a D.C. source that all the windings are fed permanently, that the current flowing in certain windings is smaller than that flowing in other windings and that the winding in which the direction of current is being reversed, is one of these certain windings, the windings in which the counterelectromotive force is zero being at that instant in series with at least one other winding in which this force is not zero.
Claim 4
Dependent Claim
173 words
A brushless D.C. motor comprising a stator having q windings with q>1, a rotor having at least one pair of poles, detector means for detecting said rotor position relative to said stator windings, arranged to determine the instant at which the counterelectromotive force induced by said rotor in at least one of said windings is zero, the occurrence of said instant resulting in a reversement in the direction of the current flowing therein, switching means for operating said current reversement, said switching means being controlled by said detector means and being respectively associated with said windings for so connecting them to a D.C. source that all the windings are fed permanently, that the current flowing in certain windings is smaller than that flowing in other windings and that the winding in which the direction of current is being reversed, is one of these certain windings, the windings in which the counterelectromotive force is zero being at that instant in series with at least one other winding in which this force is not zero.
Claim 5
Dependent Claim
94 words
A motor as claimed in claim 1, wherein said switching means arranged for forming at any instant a first group of n windings wherein n is comprised between 1 and Q-1 and a second group of windings comprising the remaining windings and wherein the current is lower than in said first group and for switching, while reversing the current in one at said windings, the windings of the first group into the second group and reciprocally except for that winding in which the current is being reversed and which remains in the same group.
Claim 6
Dependent Claim
11 words
A motor as claimed in claim 2, wherein q is odd.
Claim 7
Dependent Claim
24 words
A motor as claimed in claim 3, wherein n is equal to q-1/2 said windings being connected in series in each of said groups.
Claim 8
Dependent Claim
18 words
A motor as claimed in claim 3, said windings are connected in parallel in each of said groups.
Claim 9
Dependent Claim
39 words
A motor as claimed in claim 1, wherein said switching comprises pairs of first and second relay operated switches alternately positioned between open and closed positions in response to said detector means, each pair being associated with one winding.
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) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |