US3949253A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric motors
Assignee: National Research Development Corp UK
•
Filing: 1974-06-24
•
Granted: 1976-04-06
•
Expires: 1994-06-24
Abstract
Abstract A 3-phase, alternating current electric motor or generator having a stator winding comprising three phase-windings in start-connection wound on a stator having a slot-number not divisible by "3", yet providing a substantially balanced 3-phase winding. The stator winding coils are disposed to provide a high positive-sequence distribution factor and a low negative-sequence distribution factor. This is achieved with two of the phase-windings having an equal number of coils to each other, the third phase-winding having a different number.
Inventors
- 👤 Alexander Richard William Broadway
- 👤 William Fong
- 👤 Gordon Hindle Rawcliffe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:31
CPC Classifications
H; H02; H02K; H02K3/00; H02K3/04; H02K3/28
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
85 words
A 3-phase alternating current rotary electric machine with three phase-windings defining a pole-number and wound on a stator having a number of slots not divisible by 3; wherein two of the phase-windings each have a first number of coils and the third phase-winding has a second number of coils different from said first number; wherein the positive-sequence distribution factor of the windings is high, the negative-sequence distribution factor is low and whatever zero-sequence distribution arises is accepted; and wherein the three phase-windings are star-connected together.
Claim 2
Dependent Claim
85 words
A 3-phase alternating current rotary electric machine with three phase-windings defining a pole-number and wound on a stator having a number of slots not divisible by 3; wherein two of the phase-windings each have a first number of coils and the third phase-winding has a second number of coils different from said first number; wherein the positive-sequence distribution factor of the windings is high, the negative-sequence distribution factor is low and whatever zero-sequence distribution arises is accepted; and wherein the three phase-windings are star-connected together.
Claim 3
Dependent Claim
23 words
A 3-phase machine as claimed in claim 1, in which the said first and said second numbers of coils differ by two coils.
Claim 4
Dependent Claim
23 words
A 3-phase machine as claimed in claim 1, in which the said first and said second numbers of coils differ by one coil.
Claim 5
Dependent Claim
23 words
A 3-phase machine as claimed in claim 2, in which the said second number of coils is integrally divisible by the machine pole-number.
Claim 6
Dependent Claim
23 words
A 3-phase machine as claimed in claim 3, in which the said second number of coils is integrally divisible by the machine pole-number.
Claim 7
Dependent Claim
150 words
A 3-phase alternating current rotary electric machine with three phase-windings defining a pole-number and wound on a stator having a number of slots not divisible by 3; wherein two of the phase windings each have a first number of coils and are respectively represented by vectors N1 and N2 of equal magnitude proportional to said first number; wherein the third phase winding has a second number of coils different from said first number and is represented by a vector N3 of magnitude proportional to said second number; wherein the coils are distributed on the stator such that the vector angular spacing, in the sequence N1, N3 and N2, is (α + 120), (α + 120) and (120 - 2α), respectively, where α is a small angle not exceeding 10°; wherein N3 is substantially equal to (N1 + N2) × cos (60 +α) and wherein the three phase-windings are star-connected together.
Claim 8
Dependent Claim
150 words
A 3-phase alternating current rotary electric machine with three phase-windings defining a pole-number and wound on a stator having a number of slots not divisible by 3; wherein two of the phase windings each have a first number of coils and are respectively represented by vectors N1 and N2 of equal magnitude proportional to said first number; wherein the third phase winding has a second number of coils different from said first number and is represented by a vector N3 of magnitude proportional to said second number; wherein the coils are distributed on the stator such that the vector angular spacing, in the sequence N1, N3 and N2, is (α + 120), (α + 120) and (120 - 2α), respectively, where α is a small angle not exceeding 10°; wherein N3 is substantially equal to (N1 + N2) × cos (60 +α) and wherein the three phase-windings are star-connected together.
Claim 9
Dependent Claim
41 words
A 3-phase machine as claimed in claim 6, in which said first number of coils is an even number and the said pole-number is defined by two coil-group of said two phase-windings, the first coil-group being the inverse of the second.
Claim 10
Dependent Claim
35 words
A 3-phase machine as claimed in claim 6, wherein said stator slot-number is 32, wherein said pole-number is 4, wherein said two phase-windings each have 10 coils, and wherein said third phase-winding has 12 coils.
Claim 11
Dependent Claim
36 words
A 3-phase machine as claimed in claim 8, wherein the overall coil grouping is: 3, -2,3; -3,1, -4; 3, -3,2; -3,4, -1 the first numeral in each group of three numerals defining the third said phase-winding.
References Cited (Backward Citations)
US3233159A
Cited
US2989654A
Cited
US3299337A
Cited
US3230434A
Cited
US3335307A
Cited
US3432707A
Cited
US3515922A
Cited
US3673477A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-04-06 | 1979-10-06 | 1980-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-06 | 1983-10-06 | 1984-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-06 | 1987-10-06 | 1988-04-06 | $7700.00 | Window Closed / Lapsed |