US3634707A
Expired / Lapsed
US
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Motor
Assignee: Licentia Patent Verwaltungs GmbH
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Filing: 1969-12-04
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Granted: 1972-01-11
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Expires: 1989-12-04
Abstract
Abstract The electrical characteristics of a centrosymmetrical-shaded pole motor having salient poles and concentrated windings are improved by shaping the poles of the motor so that the angle enclosed between the pole axis and the neutral axis on the shaded pole side of the pole axis is less than that on the main pole side, the shaded pole arc is at most equal to one-fifth of the pole pitch, and the airgap adjacent to the pole has a nonuniform configuration such that the harmonics of the excitation field, and in particular, the third harmonic, are substantially eliminated, whereby the starting torque, the breakdown torque and the efficiency of the motor are improved.
Inventors
- 👤 Siegfried Tillner
- 👤 Heinz Heilmann
- 👤 Joseph Ludemann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:56
CPC Classifications
H; H02; H02K; H02K17/00; H02K17/02; H02K17/04; H02K17/10
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
176 words
In a shaded-pole motor having centrosymmetrical construction and concentrated windings on salient poles and a partially widened airgap, the improvement wherein each of such salient poles is shaped so that: a. the angle enclosed between the pole axis and the neutral axis, on the shaded-pole side of the pole axis is less than that on the main pole side; b. the shaded-pole arc is at most equal to one-fifth of the pole pitch; and c. the airgap adjacent to the pole has a configuration across the main pole portion of each pole face which conforms substantially to the equation: where: delta x the desired airgap length at each angular position x across the pole pitch; delta m a preselected median airGap length; B1 the peak value of the fundamental component of the excitation flux field of a similar motor having an unvarying airgap length; B3 the peak value of the third harmonic component of the flux field of the similar motor; and x the angular position of each point along the pole pitch in electrical degrees.
Claim 2
Dependent Claim
176 words
In a shaded-pole motor having centrosymmetrical construction and concentrated windings on salient poles and a partially widened airgap, the improvement wherein each of such salient poles is shaped so that: a. the angle enclosed between the pole axis and the neutral axis, on the shaded-pole side of the pole axis is less than that on the main pole side; b. the shaded-pole arc is at most equal to one-fifth of the pole pitch; and c. the airgap adjacent to the pole has a configuration across the main pole portion of each pole face which conforms substantially to the equation: where: delta x the desired airgap length at each angular position x across the pole pitch; delta m a preselected median airGap length; B1 the peak value of the fundamental component of the excitation flux field of a similar motor having an unvarying airgap length; B3 the peak value of the third harmonic component of the flux field of the similar motor; and x the angular position of each point along the pole pitch in electrical degrees.
Claim 3
Dependent Claim
40 words
The motor as defined in claim 1 wherein the main pole tip at its point of connection has a width equal to about one-third to one-fourth of its pole arc and becomes continuously narrower in the form of a sickle.
Claim 4
Dependent Claim
126 words
shaping the pole face of each salient pole so that the airgap adjacent to the pole has a configuration across the main pole portion thereof which conforms substantially to the equation: delta x the desired airgap length at each angular position x across the pole pitch; delta m a preselected median airgap length; B1 the peak value of the fundamental component of the excitation flux field of a similar motor having an unvarying airgap length; B3 the peak value of the third harmonic component of the flux field of the similar motor; sigma 3 the phase angle of the third harmonic component relative to the fundamental component of the flux field; and x the angular position of each point along the pole pitch in electrical degrees.
Claim 5
Dependent Claim
126 words
shaping the pole face of each salient pole so that the airgap adjacent to the pole has a configuration across the main pole portion thereof which conforms substantially to the equation: delta x the desired airgap length at each angular position x across the pole pitch; delta m a preselected median airgap length; B1 the peak value of the fundamental component of the excitation flux field of a similar motor having an unvarying airgap length; B3 the peak value of the third harmonic component of the flux field of the similar motor; sigma 3 the phase angle of the third harmonic component relative to the fundamental component of the flux field; and x the angular position of each point along the pole pitch in electrical degrees.
Claim 6
Dependent Claim
49 words
A motor as defined in claim 1 wherein with an inducted magnetic flux in the yoke of the stator of the said motor of approximately 14,000 Gauss, the inducted magnetic flux in the pole tip is not more than 18,000 Gauss, and approximately 4,000 Gauss in the said airgap.
Claim 7
Dependent Claim
60 words
A motor as defined in claim 1 wherein said motor is the type having magnetic bridges between the poles formed by slits in the stator laminations to provide a narrow magnetic passage, said slit having a depth which causes a stray flux, when the motor is idling without load, to be approximately 9 to 15 percent of the total flux.
Claim 8
Dependent Claim
40 words
A motor as defined in claim 1 wherein each said salient pole is shaped to have a minimum airgap length adjacent to the main pole portion at a pole pitch angle of 30 electrical degrees measured from the neutral axis.
Claim 9
Dependent Claim
37 words
A motor as defined in claim 1 wherein the variation of the length of the airgap adjacent to the main pole portion extends over a pole arc of approximately 60 electrical degrees measured from the neutral axis.
Claim 10
Dependent Claim
37 words
A motor as defined in claim 5 wherein the variation of the length of the airgap adjacent to the main pole portion extends over a pole arc of approximately 60 electrical degrees measured from the neutral axis.
Claim 11
Dependent Claim
35 words
A motor as defined in claim 1 wherein the airgap is also lengthened adjacent to the shaded portion of each pole, with the maximum airgap length occurring in the center region of the shaded-pole arc.
Claim 12
Dependent Claim
64 words
A motor as defined in claim 1 wherein the number of rotor grooves is increased with respect to the diameter of the rotors so that a rotor having a diameter of 30 mm. has 20 or more associated grooves, of 38 mm. has 22 or more grooves, of 45 mm. has 28 or more grooves, and of 55 mm. has 32 and more grooves.
Claim 13
Dependent Claim
13 words
A motor as defined in claim 9 wherein the grooves are magnetically open.
Claim 14
Independent Claim
21 words
A method of improving the operating characteristics of a shaded-pole motor of centrosymmetrical construction having salient poles and concentrated windings comprising:
Claim 15
Independent Claim
21 words
A method of improving the operating characteristics of a shaded-pole motor of centrosymmetrical construction having salient poles and concentrated windings comprising:
Claim 16
Dependent Claim
106 words
A shaded-pole motor as defined in claim 1 wherein each of said salient poles is shaped so that the airgap aDjacent to the pole has a configuration across the main pole portion of each pole face which conforms substantially to the equation: where: B5 the peak value of the fifth harmonic component of the flux field of the similar motor; Bn the peak value of the nth harmonic component of the flux field on the similar motor; and sigma 3, sigma 5, and sigma n the phase angles of the third, fifth and nth harmonic components, respectively, relative to the fundamental component of the flux field.
Claim 17
Dependent Claim
103 words
The method defined in claim 11 wherein the pole face of each salient pole is shaped so that the airgap adjacent to the pole has a configuration across the main pole portion of each pole face which conforms substantially to the equation: where: B5 the peak value of the fifth harmonic component of the flux field of the similar motor; Bn the peak value of the nth harmonic component of the flux field on the similar motor; and sigma 5, and sigma n the phase angles of the fifth and nth harmonic components, respectively, relative to the fundamental component of the flux field.
References Cited (Backward Citations)
US2490021A
Cited
US2773999A
Cited
US2845553A
Cited
US2815460A
Cited
US3214619A
Cited
US3500092A
Cited
FR1537771A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |