US3864965A
Expired / Lapsed
US
⏱️ 0.0 years remaining
D. C. dynamometer speed control circuit
Assignee: Mcculloch Corp
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Filing: 1973-02-05
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Granted: 1975-02-11
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Expires: 1993-02-05
Abstract
Abstract A direct current dynamometer speed control circuit including transistors connected in series with the dynamometer field coil and the generator field coil for controlling the current in the field coils in a continuously variable manner to effect smooth mode changes between an absorbing mode and a motoring mode responsively to dynamometer speed changes. The desired speed of the dynamometer is established by a preset d.c. potential onto which is impressed a rectified 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 which function as threshold circuits for applying full current to the generator field coil and/or reducing the dynamometer field coil current for large drops in dynamometer speed. A circuit is provided for preventing the dynamometer field from dropping below a predetermined value for preventing dynamometer runaway. A novel current sharing transistor circuit is also disclosed.
Inventors
- 👤 Harold E Anderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:05
CPC Classifications
G; G01; G01L; G01L3/00; G01L3/16; G01L3/22
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
241 words
A dynamic speed control system for a direct current dynamometer including dynamometer means having a dynamometer field coil and generator means having a generator field coil, the dynamometer and generator means having armatures connected in series, and the dynamometer having an input/output shaft adapted for connection to an engine under test, comprising: tachometer means for generating a signal having an amplitude related to the speed of the input/output shaft of the dynamometer; and, means for controlling the current in the dynamometer and generator field coils responsively to the amplitude of said tachometer signal to maintain the rotational speed of the input/output shaft constant, said current controlling means including transistor means continuously variable in the degree of conduction and operably coupled to said tachometer signal for varying the current to the coils to thereby vary the operation of the dynamometer between motoring and braking modes in response to small changes in the speed of the input/output shaft, said transistor means including a first transistor means for controlling the current in the generator field coil, a second transistor means for controlling the current in the dynamometer field coil, and means for reducing the conduction of one of said transistor means and increasing the conduction of the other of said transistor means responsively to a change in said tachometer signal, the degree of conduction of each of said transistors means being independent of the degree of conduction of the other of said transistor means.
Claim 2
Dependent Claim
241 words
A dynamic speed control system for a direct current dynamometer including dynamometer means having a dynamometer field coil and generator means having a generator field coil, the dynamometer and generator means having armatures connected in series, and the dynamometer having an input/output shaft adapted for connection to an engine under test, comprising: tachometer means for generating a signal having an amplitude related to the speed of the input/output shaft of the dynamometer; and, means for controlling the current in the dynamometer and generator field coils responsively to the amplitude of said tachometer signal to maintain the rotational speed of the input/output shaft constant, said current controlling means including transistor means continuously variable in the degree of conduction and operably coupled to said tachometer signal for varying the current to the coils to thereby vary the operation of the dynamometer between motoring and braking modes in response to small changes in the speed of the input/output shaft, said transistor means including a first transistor means for controlling the current in the generator field coil, a second transistor means for controlling the current in the dynamometer field coil, and means for reducing the conduction of one of said transistor means and increasing the conduction of the other of said transistor means responsively to a change in said tachometer signal, the degree of conduction of each of said transistors means being independent of the degree of conduction of the other of said transistor means.
Claim 3
Dependent Claim
61 words
The system of claim 1 wherein the current through said transistor means is continuously variable above a first predetermined value, and wherein said means for increasing and reducing said transistor means conductivity includes means for rendering said first transistor means fully conductive responsively to the reduction of said tachometer signal below a second predetermined value related to said first predetermined value.
Claim 4
Dependent Claim
69 words
The system of claim 2 wherein said means for rendering said first transistor means fully conductive includes means for interrupting said tachometer signal responsively to a reduction thereof below said second predetermined value; and, means for applying a potential to the base electrode of said first transistor means sufficient to bias said first transistor means into full conduction responsively to the interruption of the application of said tachometer signal.
Claim 5
Dependent Claim
34 words
The system of claim 3 further including means for applying a potential sufficient to reduce the conduction of said second transistor means to a predetermined level responsively to the interruption of said tachometer signal.
Claim 6
Dependent Claim
48 words
The system of claim 2 wherein said first and second transistor means each include a plurality of transistors, the base and collector electrodes of said transistors being connected together and the emitter electrodes of each of said transistors being connected through an impedance element to a common point.
Claim 7
Dependent Claim
34 words
The system of claim 1 including means for limiting the bias of said second transistor to a predetermined value inSuring the conduction thereof and thus the passage of current through the dynamometer field coil.
Claim 8
Dependent Claim
143 words
A dynamic speed control for a direct current dynamometer having a generator field coil and a dynamometer field coil comprising: means for generating a d.c. signal having an amplitude related to the speed of the dynamometer; and, continuously variable current control means including transistor means for continuously varying the current through the coils responsively to the amplitude of said d.c. signal to thereby control the speed of the dynamometer responsively to variation in the speed of the dynamometer above and below a predetermined base speed, said current control means including: a first transistor for controlling the current in the generator field coil; a second transistor for controlling the current in the dynamometer field coil; and, means for reducing the conduction of one of said transistors and increasing the conduction of the other of said transistors responsively to a change in said control potential.
Claim 9
Dependent Claim
143 words
A dynamic speed control for a direct current dynamometer having a generator field coil and a dynamometer field coil comprising: means for generating a d.c. signal having an amplitude related to the speed of the dynamometer; and, continuously variable current control means including transistor means for continuously varying the current through the coils responsively to the amplitude of said d.c. signal to thereby control the speed of the dynamometer responsively to variation in the speed of the dynamometer above and below a predetermined base speed, said current control means including: a first transistor for controlling the current in the generator field coil; a second transistor for controlling the current in the dynamometer field coil; and, means for reducing the conduction of one of said transistors and increasing the conduction of the other of said transistors responsively to a change in said control potential.
Claim 10
Dependent Claim
71 words
The speed control of claim 7 wherein said means for generating a d.c. signal includes: means for generating a d.c. signal having a predetermined amplitude; means for generating a d.c. signal having an amplitude variable in response to dynamometer speed; means for combining said d.c. signals to produce a control potential; and, means for applying said control potential to said transistor means to control the amount of current in said coils.
Claim 11
Dependent Claim
35 words
The speed control of claim 7 wherein said means for increasing and reducing conductivity includes means for rendering said first transistor fully conductive responsively to a reduction in said control potential below a predetermined value.
Claim 12
Dependent Claim
60 words
The speed control of claim 9 wherein said means for rendering said first transistor fully conductive includes means for interrupting the application of said control potential to said transistors and means for applying a potential to the base electrode of said first transistor sufficient to bias said first transistor into full conduction responsively to said control potential application interrupting means.
Claim 13
Dependent Claim
36 words
The speed control of claim 7 wherein said means for increasing and reducing transistor conductivity includes means for rendering said first transistor fully conductive responsively to a reduction in said d.c. signal below a predetermined value.
Claim 14
Dependent Claim
43 words
The system of claim 7 wherein said transistors include a plurality of transistors, the base and collector electrodes of said transistors being connected together and the emitter electrodes of each of said transistors being connected through an impedance element to a common point.
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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) | 1978-02-10 | 1978-08-12 | 1979-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-10 | 1982-08-12 | 1983-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-10 | 1986-08-12 | 1987-02-11 | $7700.00 | Window Closed / Lapsed |