US4572999A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Brushless tachometer
Assignee: Kollmorgen Technologies Corp
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Filing: 1983-06-14
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Granted: 1986-02-25
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Expires: 2003-06-14
Abstract
Abstract A brushless tachometer in which output signal switching is achieved using field effect transistors and which is capable of achieving linearity over a broad range, particularly the zero speed region. According to a preferred embodiment, the brushless tachometer is operated in a current mode as part of the servo loop to substantially reduce tachometer voltage switching requirements. A ROM can be used to control commutation switching. Commutation is preferable line-to-neutral to reduce ripple.
Inventors
- 👤 Philip S. Coulon, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:41
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/42; G01P3/44; G01P3/46; G01P3/465; Y; Y10; Y10S; Y10S322/00; Y10S322/05
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
85 words
A DC tachometer comprising an alternator including a stator, a rotor, and windings for producing an alternating signal proportional to the speed of rotation; a rotor position sensor; a field effect transistor switching circuit controlled by said position sensor to produce a DC signal proportional to rotor speed from said alternating signal; and wherein said position sensor indicates position by a digital code and further including a read only memory for converting said digital code into control signals for said field effect transistor switching circuit.
Claim 2
Dependent Claim
85 words
A DC tachometer comprising an alternator including a stator, a rotor, and windings for producing an alternating signal proportional to the speed of rotation; a rotor position sensor; a field effect transistor switching circuit controlled by said position sensor to produce a DC signal proportional to rotor speed from said alternating signal; and wherein said position sensor indicates position by a digital code and further including a read only memory for converting said digital code into control signals for said field effect transistor switching circuit.
Claim 3
Dependent Claim
149 words
In a motor control system of the type including a motor and a tachometer in a servo loop, the servo loop including a summing circuit for summing a command signal and a tachometer feedback signal at a summing junction, the improvement comprising; said tachometer being of the type including a rotor, a stator, windings for producing an alternating signal proportional to the speed of rotation, and a rotor position sensor; at least two field effect transistor switching circuits connected to each of said windings, said transistors being controlled by said position sensor to produce a DC signal proportional to rotor speed from said alternating signal and being controlled to operate in pairs to complete circuit paths between the windings and the summing junction; and input resistors for developing said tachometer feedback signal supplied to said summing junction being located between said windings and said field effect transistor switching circuits.
Claim 4
Dependent Claim
149 words
In a motor control system of the type including a motor and a tachometer in a servo loop, the servo loop including a summing circuit for summing a command signal and a tachometer feedback signal at a summing junction, the improvement comprising; said tachometer being of the type including a rotor, a stator, windings for producing an alternating signal proportional to the speed of rotation, and a rotor position sensor; at least two field effect transistor switching circuits connected to each of said windings, said transistors being controlled by said position sensor to produce a DC signal proportional to rotor speed from said alternating signal and being controlled to operate in pairs to complete circuit paths between the windings and the summing junction; and input resistors for developing said tachometer feedback signal supplied to said summing junction being located between said windings and said field effect transistor switching circuits.
Claim 5
Dependent Claim
30 words
The system according to claim 2 further including means for limiting the potential across said switching circuit to the operating range of the field effect transistor in said switching circuit.
Claim 6
Dependent Claim
20 words
The system according to claim 3 wherein said means for limiting the potential across said switching circuit includes Zener diodes.
Claim 7
Dependent Claim
33 words
The system according to claim 3 wherein said means for limiting the potential across said switching circuit includes switches for connecting resistance across said windings when not supplying current to said summing junction.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-24 | 1989-08-26 | 1990-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-24 | 1993-08-26 | 1994-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-24 | 1997-08-26 | 1998-02-25 | $7700.00 | Window Closed / Lapsed |