US3838323A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Eddy current dynamometer speed control circuit and method
Assignee: Mcculloch Corp
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Filing: 1973-02-05
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Granted: 1974-09-24
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Expires: 1993-02-05
Abstract
Abstract An eddy current dynamometer speed control circuit includes transistors connected in series with the motor field coil and the absorbing field coil to control the current in the coils in a continuously variable manner to effect changes between a braking mode and a motoring mode responsively to dynamometer speed changes. The speed control circuit utilizes a regulated voltage onto which is impressed a tachometer signal having an amplitude related to the speed of the dynamometer input/output shaft. Control voltages for the transistors are applied through Zener diodes each of which function as a threshold circuit to control the initial acceleration of the input/output shaft of the dynamometer and for causing a full motoring field to be applied responsively to abnormally large speed drops for quick recovery. A current sharing transistor circuit is also disclosed.
Inventors
- 👤 H Anderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:24
CPC Classifications
H; H02; H02K; H02K49/00; H02K49/02; H02K49/04; G; G01; G01L; G01L3/00; G01L3/16; G01L3/22; Y; Y10; Y10S; Y10S388/00; Y10S388/923; Y10S388/93; Y10S388/932
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
90 words
A dynamic speed control system for an eddy current dynamometer including a motor field coil, an absorbing field coil and an eddy current drum mechanically connected to an input/output shaft, comprising: tachometer means for generating a signal having an amplitude related to the speed of the input/output shaft of the dynamometer; and, continuously variable transistor means for controlling in a continuously variable manner the current in the absorbing and motor field coils responsively to the amplitude of said tachometer signal to regulate the rotational speed of the dynamometer input/output shaft.
Claim 2
Dependent Claim
90 words
A dynamic speed control system for an eddy current dynamometer including a motor field coil, an absorbing field coil and an eddy current drum mechanically connected to an input/output shaft, comprising: tachometer means for generating a signal having an amplitude related to the speed of the input/output shaft of the dynamometer; and, continuously variable transistor means for controlling in a continuously variable manner the current in the absorbing and motor field coils responsively to the amplitude of said tachometer signal to regulate the rotational speed of the dynamometer input/output shaft.
Claim 3
Dependent Claim
41 words
The system of claim 1 wherein said current control means includes: means for providing a d.c. signal; means responsive to the d.c. and tachometer signals for providing a control signal; and, means for applying said control signal to said transistor means.
Claim 4
Dependent Claim
46 words
The system of claim 2 wherein said transistor means includes: first current valving means for controlling the current in the absorbing field coil; and, second current valving means for controlling the current in the motor field coil responsive to current through said first circuit valving means.
Claim 5
Dependent Claim
34 words
The system of claim 3 and further including means for significantly increasing the response of said second current valving means to the control signal for values of the control signal below a predetermined threshold.
Claim 6
Dependent Claim
91 words
The system of claim 2 wherein the control signal includes a first control potential and wherein said transistor means includes first and second transistors, the first transistor controlling current in the absorbing field coil responsively to the first control potential and the second transistor controlling current in the motor field coil, the current through the first transistor determining a second control potential at one end of the absorbing field coil, and means for applying the second control potential to the second transistor to control the current in the motor field coil.
Claim 7
Dependent Claim
25 words
The system of claim 5 and further including means for blocking said control potentials to each of said transistors for potential values below predetermined thresholds.
Claim 8
Dependent Claim
111 words
The system of claim 6 wherein said transistor means includes a plurality of cascaded transistors, the collector electrodes of said cascaded transistors being interconnected and the emitter electrode of each of said cascaded transistors being connected to the base electrode of the next succeeding transistor in the cascade, the emitter electrode of the last of said cascaded transistors being connected to the base electrodes of a plurality of load transistors, the collector electrodes of said plurality of load transistors being interconnected with the collector electrodes of said plurality of cascaded transistors and the emitter electrode of each of said load transistors being connected through an impedance element to a common terminal.
Claim 9
Dependent Claim
106 words
The system of claim 1 wherein said transistor means includes a plurality of cascaded transistors, the collector electrodes of said cascaded transistors being interconnected and the emitter electrode of each of said cascaded transistors being connected to the base electrode of the next succeeding transistor in the cascade, the emitter electrode of the last of said cascaded transistors being connected to the base electrodes of a plurality of load transistors, the collector electrodes of said load transistors being interconnected with the collector electrodes of said cascaded transistors and the emitter electrode of each of said transistors being connected through an impedance element to a common terminal.
Claim 10
Dependent Claim
84 words
A dynamic speed control for an eddy current dynamometer having a motor field coil and an absorbing field coil comprising: means for generating a d.c. signal having an amplitude related to the speed of said dynamometer; and, continuously variable current control means for varying in a continuously variable manneR the current through the coils responsively to the amplitude of said d.c. signal to control the speed of the dynamometer responsively to variations in the speed of the dynamometer above and below a predetermined speed.
Claim 11
Dependent Claim
84 words
A dynamic speed control for an eddy current dynamometer having a motor field coil and an absorbing field coil comprising: means for generating a d.c. signal having an amplitude related to the speed of said dynamometer; and, continuously variable current control means for varying in a continuously variable manneR the current through the coils responsively to the amplitude of said d.c. signal to control the speed of the dynamometer responsively to variations in the speed of the dynamometer above and below a predetermined speed.
Claim 12
Dependent Claim
131 words
The dynamic speed control of claim 9 wherein said control means includes transistor means responsive to said d.c. signal for varying the current through the coils, said transistor means including a plurality of cascaded transistors, the collector electrodes of said cascaded transistors being interconnected and the emitter electrode of each of said cascaded transistors being connected to the base electrode of the next succeeding transistor in the cascade, the emitter electrode of the last of said cascaded transistors being connected to the base electrodes of a plurality of load transistors, the collector electrodes of said plurality of load transistors being interconnected with the collector electrodes of said plurality of cascaded transistors and the emitter electrode of each of said load transistors being connected through an impedance element to a common terminal.
Claim 13
Independent Claim
63 words
A method for controlling the speed of an eddy current dynamometer having motoring and absorbing coils each energized through an electrically conductive path from a source of electric current, comprising the step of regulating the current in each of the coils in a continuously variable manner responsively to the speed of the dynamometer, by continuously varying the electrical conductivity of each said path.
Claim 14
Independent Claim
63 words
A method for controlling the speed of an eddy current dynamometer having motoring and absorbing coils each energized through an electrically conductive path from a source of electric current, comprising the step of regulating the current in each of the coils in a continuously variable manner responsively to the speed of the dynamometer, by continuously varying the electrical conductivity of each said path.
Claim 15
Dependent Claim
89 words
The method of claim 11 wherein said regulating step includes the steps of: applying current to the motoring coil to permit the dynamometer to achieve a predetermined base speed, applying current to the absorbing coil and reducing current to the motoring coil by amounts related to the amount the speed of the dynamometer exceeds the predetermined base speed; and, reducing current to the absorbing coil and increasing current to the motoring coil by amounts related to the amount the speed of the dynamometer is less than said predetermined speed.
References Cited (Backward Citations)
US3450912A
Cited
US3599764A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-23 | 1978-03-25 | 1978-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-23 | 1982-03-25 | 1982-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-23 | 1986-03-25 | 1986-09-24 | $7700.00 | Window Closed / Lapsed |