Patent US3663877A successfully refreshed from Google Patents.
US3663877A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Brushless dc motor including tachometer commutation circuit
Assignee: Ampex Corp
•
Filing: 1970-04-02
•
Granted: 1972-05-16
•
Expires: 1990-04-02
Abstract
Abstract A DC motor formed of a stationary segmented armature winding and a two pole permanent magnet rotor, wherein a pair of Hall effect generators are mounted 90* apart within the armature winding to develop a pair of quadrature related sinusoidal signals and wherein a tachometer is disposed to generate a plurality of pulses for each revolution of the rotor. Commutation for the armature windings is achieved by an electronic switching circuit connected to receive the Hall generator signals and the tachometer pulse signal and respond to the phase relationships between these various signals to develop multiple phase switching signals in which the phase angles thereof are precisely correlated to the angle of rotation of the rotor. The motor is illustrated in the environment of a servo controlled magnetic tape transport, wherein the commutation signals or switching signals associated therewith serve as multi-phase tachometer or angular position indicating signals in a special servo controlled operation.
Inventors
- 👤 Harold V Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:40
CPC Classifications
H; H02; H02P; H02P6/00; H02P6/06; H02K; H02K29/00; H02K29/06; H02K29/08; H02K29/14
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
162 words
A dynamoelectric apparatus comprising, armature winding means and housing therefor; magnetic field producing means disposed for relative rotation with respect to said winding means and housing; magnetic field sensor means carried by said housing in fixed position relative to said winding means and developing signals proportional to the phase angle of relative rotation of said field means, tachometer means other than said sensor means responsive to said relative rotation of said field means generating a set of electrical pulses for each full relative revolution thereof, and commutation switching circuit means connected to said armature winding means and having switching states selectively energizing said winding means in response to said sensor means and said tachometer means, said switching circuit being responsive to each electrical pulse from said tachometer means to undergo a transition between switching states and being responsive to signals from said sensor means to cause said switching states to assume a particular phase relationship to the rotation of said field means.
Claim 2
Dependent Claim
162 words
A dynamoelectric apparatus comprising, armature winding means and housing therefor; magnetic field producing means disposed for relative rotation with respect to said winding means and housing; magnetic field sensor means carried by said housing in fixed position relative to said winding means and developing signals proportional to the phase angle of relative rotation of said field means, tachometer means other than said sensor means responsive to said relative rotation of said field means generating a set of electrical pulses for each full relative revolution thereof, and commutation switching circuit means connected to said armature winding means and having switching states selectively energizing said winding means in response to said sensor means and said tachometer means, said switching circuit being responsive to each electrical pulse from said tachometer means to undergo a transition between switching states and being responsive to signals from said sensor means to cause said switching states to assume a particular phase relationship to the rotation of said field means.
Claim 3
Dependent Claim
58 words
The apparatus as defined in claim 1, wherein said field sensor means comprise a pair of Hall effect devices carried by the housing for said winding means, said devices being mounted in quadrature relation with respect to the axis of rotation of said field producing means and said devices developling quadrature related signals in response to such rotation.
Claim 4
Dependent Claim
46 words
The apparatus as defined in claim 2, wherein said armature winding means has a preselected number of winding segments, and said tachometer means is further defined by said set of electrical pulses being equal to the number of said winding segments and occurring at spaced intervals.
Claim 5
Dependent Claim
42 words
The apparatus as defined by claim 1, wherein said field producing means comprises a two pole permanent magnet mounted for rotation, and said armature winding means comprise a plurality of winding segments mounted circumferentially about the axis of rotation of said magnet.
Claim 6
Dependent Claim
57 words
The apparatus as defined in claim 4, said tachometer means comprising a disc member mounted for joint rotation with said permanent magnet, said disc member being formed with a plurality of index means, and a pick-up means mounted stationary relative to said member and being responsive to said index means for developing said set of electrical pulses.
Claim 7
Dependent Claim
79 words
The apparatus as defined in claim 2, said commutation switching circuit means comprising a Hall generator signal decoder means having a pair of phase splitting means each connected to receive the signal from one of said devices and develop opposing phase signals for each of the quadrature related signals, and circuit means responsive to said opposing phase signals issuing a unique switching signal for each quarter of relative rotation between said armature winding means and said field producing means.
Claim 8
Dependent Claim
80 words
The apparatus as defined by claim 6, said commutation switching circuit means comprising a shift counter clock having inputs connected to receive said tachometer pulses and having direct set and direct clear inputs connected to receive the signals developed by said Hall generator signal decoder, said shift counter having outputs issuing a set of phase related switching signals having the phases thereof determined by said Hall decoder signals and having the leading and trailing edges determined by said tachometer pulses.
References Cited (Backward Citations)
US3264539A
Cited
US3274471A
Cited
US3465224A
Cited
US3461367A
Cited
US3440506A
Cited
US3448359A
Cited
US3435314A
Cited
US3435310A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-16 | 1975-11-15 | 1976-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-16 | 1979-11-15 | 1980-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-16 | 1983-11-15 | 1984-05-16 | $7700.00 | Window Closed / Lapsed |