US4755702A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Three-phase induction motor
Assignee: NEC Corp
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Filing: 1987-01-06
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Granted: 1988-07-05
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Expires: 2007-01-06
Abstract
Abstract A three-phase induction motor includes winding slots and a stator winding. The number of winding slots per pole per phase is a noninteger. The stator winding is a three-phase balanced winding. A pitch s of the winding satisfies s=(r-t)/r or s=r/(r+t) (where t is an odd number and r is the order of a harmonic wave to be suppressed).
Inventors
- 👤 Hiroshi Iijima
- 👤 Tetsuo Endo
- 👤 Yukio Miyamoto
- 👤 Kiyokazu Okamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:21
CPC Classifications
H; H02; H02K; H02K3/00; H02K3/04; H02K3/28
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
85 words
A three phase induction motor, comprising: a rotor having a rotor winding thereon; and a stator having winding slots formed therein and a stator winding wound in said slots as a three-phased balanced winding; the number of said winding slots per pole per phase being a non-integer; the pitch of said stator winding satisfying the equation s=(r-t)/r or s=r/(r+t), where t is an odd number and r is the order of an undersirable harmonic wave, whose generation in said rotor winding is to be suppressed.
Claim 2
Dependent Claim
85 words
A three phase induction motor, comprising: a rotor having a rotor winding thereon; and a stator having winding slots formed therein and a stator winding wound in said slots as a three-phased balanced winding; the number of said winding slots per pole per phase being a non-integer; the pitch of said stator winding satisfying the equation s=(r-t)/r or s=r/(r+t), where t is an odd number and r is the order of an undersirable harmonic wave, whose generation in said rotor winding is to be suppressed.
Claim 3
Dependent Claim
8 words
A motor according to claim 1, wherein t=1.
Claim 4
Dependent Claim
35 words
A motor according to claim 2, wherein said stator includes 15 slots, 2 poles, three phases and 2.5 slots per pole per phase, and the order of said harmonic wave to be suppressed is 5.
Claim 5
Dependent Claim
35 words
A motor according to claim 2, wherein said stator includes 21 slots, two poles, three phases and 3.5 slots per pole per phase, and the order of said harmonic wave to be suppressed is 7.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-07-05 | 1992-01-04 | 1992-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-05 | 1996-01-04 | 1996-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-05 | 2000-01-04 | 2000-07-05 | $7700.00 | Window Closed / Lapsed |