Patent US1874248A successfully refreshed from Google Patents.
Patent US3909645A successfully refreshed from Google Patents.
US3909645A
Expired / Lapsed
US
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Permanent magnet motor-tachometer having a single non-ferrous armature wound with two mutually-insulated windings each connected to a separate commutator
Assignee: Singer Co
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Filing: 1974-07-10
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Granted: 1975-09-30
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Expires: 1994-07-10
Abstract
Abstract A structure for a permanent magnet motor-tachometer is disclosed wherein a single, non-ferrous, slotted armature rotating in a flux field supplied by permanent magnets is wound in the same slots with two mutually insulated windings each of which is connected to a separate commutator at opposite ends of the armature. Due to the absence of magnetic material in the armature, coupled with the low permeability of the permanent magnets, the two windings are essentially magnetically isolated and there is little or no transformer action between the two windings.
Inventors
- 👤 John A Herr
- 👤 Wolfgang Jaffe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:19
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/42; G01P3/44; G01P3/46; G01P3/465; H; H02; H02K; H02K23/00; H02K23/26; H02K23/36; H02K7/00; H02K7/20
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
57 words
A motor-tachometer comprising a permanent-magnet field formed with a single air-gap, a single non-magnetic cylindrical armature mounted for rotation in said air-gap, peripherally-spaced slots formed in said armature, a motor winding and a mutually insulated tachometer winding would in the same armature slots, said windings being connected to separate commutators located on opposite ends of the armature.
Claim 2
Dependent Claim
57 words
A motor-tachometer comprising a permanent-magnet field formed with a single air-gap, a single non-magnetic cylindrical armature mounted for rotation in said air-gap, peripherally-spaced slots formed in said armature, a motor winding and a mutually insulated tachometer winding would in the same armature slots, said windings being connected to separate commutators located on opposite ends of the armature.
Claim 3
Dependent Claim
24 words
A motor-tachometer according to claim 1 in which said peripherally spaced slots are formed substantially parallel to the axis of rotation of said armature.
Claim 4
Dependent Claim
31 words
A motor-tachometer according to claim 1 in which the tachometer winding occupies only the bottom portion of the slots and the motor winding occupies only the top portion of the slots.
Claim 5
Dependent Claim
22 words
A motor-tachometer according to claim 1 in which the field structure comprises salient poles of low-permeability permanent magnet material facing said armature.
Claim 6
Dependent Claim
15 words
A motor-tachometer according to claim 4 in which said poles are made of rare-earth alloys.
References Cited (Backward Citations)
US1059351A
Cited
US2332877A
Cited
US829801A
Cited
US994058A
Cited
US2717321A
Cited
US3436573A
Cited
US3424578A
Cited
US3638055A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |