US3867678A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and means for measuring the torque delivered by an electric motor
Assignee: Caterpillar Global Mining LLC
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Filing: 1973-02-15
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Granted: 1975-02-18
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Expires: 1993-02-15
Abstract
Abstract A torque feedback signal for the control system of a motorgenerator set is generated by a torque feedback circuit which includes a differentiator and a current sensing circuit. The differentiator is connected to sense generator output voltage and provide an acceleration torque signal which is proportional to the first derivative of generator voltage. The current sensing circuit provides an induced torque signal proportional to motor armature current, and this is summed with the acceleration torque signal to provide a feedback signal proportional to the torque at the motor rotor. A second embodiment is shown which separates the induced torque into steady-state and transient components. The transient component is summed with the acceleration torque signal to provide a transient torque feedback signal, and the steadystate induced torque component is fed back to establish a torque limit.
Inventors
- 👤 Thomas A Stoner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:34
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/34; H02P7/347
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
94 words
A method of generating a signal proportional to the force delivered to a load driven by an energy conversion machine, the steps comprising: indirectly sensing the force induced by said energy conversion machine and generating an electrical signal proportional to said induced force; indirectly sensing the acceleration force generated by the inertias of the energy conversion machine and load, and generating an electrical signal proportional to said acceleration force; and arithmetically summing the electrical signals representing induced force and acceleration force to provide a signal proportional to the total force delivered to the load.
Claim 2
Independent Claim
94 words
A method of generating a signal proportional to the force delivered to a load driven by an energy conversion machine, the steps comprising: indirectly sensing the force induced by said energy conversion machine and generating an electrical signal proportional to said induced force; indirectly sensing the acceleration force generated by the inertias of the energy conversion machine and load, and generating an electrical signal proportional to said acceleration force; and arithmetically summing the electrical signals representing induced force and acceleration force to provide a signal proportional to the total force delivered to the load.
Claim 3
Independent Claim
84 words
A method of generating a signal proportional to the torque delivered to a load driven by an electric motor, the steps comprising: indirectly sensing the torque induced by said motor and generating an electrical signal proportional thereto; indirectly sensing the acceleration torque produced by the inertias of the motor rotor and load, and generating an electrical signal proportional thereto; and arithmetically summing the electrical signals representing induced torque and acceleration torque to provide a torque signal proportional to the torque delivered to the load.
Claim 4
Independent Claim
84 words
A method of generating a signal proportional to the torque delivered to a load driven by an electric motor, the steps comprising: indirectly sensing the torque induced by said motor and generating an electrical signal proportional thereto; indirectly sensing the acceleration torque produced by the inertias of the motor rotor and load, and generating an electrical signal proportional thereto; and arithmetically summing the electrical signals representing induced torque and acceleration torque to provide a torque signal proportional to the torque delivered to the load.
Claim 5
Dependent Claim
56 words
The method as recited in claim 2 in which the motor is a d-c motor, the induced torque is indirectly sensed by measuring motor armature current, and the acceleration torque is indirectly sensed by measuring the voltage of motor armature circuit windings and differentiating such measured voltage to obtain a signal proportional to the acceleration torque.
Claim 6
Dependent Claim
122 words
In a electro-mechanical drive system having an electric motor connected to a mechanical load and to a control system, a circuit for generating a torque feedback signal to the control system, the combination comprising: an induced torque sensor connected to the motor and being operable to generate a signal proportional to the induced torque at the motor rotor; an acceleration torque sensor connected to the motor and being operable to generate a signal proportional to the torque developed by the inertias of the motor rotor and the load during speed changes; and summing means connected to receive the induced torque signal and the acceleration torque signal, said summing means being operable to arithmetically add their magnitudes to provide the torque feedback signal.
Claim 7
Dependent Claim
122 words
In a electro-mechanical drive system having an electric motor connected to a mechanical load and to a control system, a circuit for generating a torque feedback signal to the control system, the combination comprising: an induced torque sensor connected to the motor and being operable to generate a signal proportional to the induced torque at the motor rotor; an acceleration torque sensor connected to the motor and being operable to generate a signal proportional to the torque developed by the inertias of the motor rotor and the load during speed changes; and summing means connected to receive the induced torque signal and the acceleration torque signal, said summing means being operable to arithmetically add their magnitudes to provide the torque feedback signal.
Claim 8
Dependent Claim
80 words
The circuit as recited in claim 4 wherein said motor is a d-c motor, said induced torque sensor connects to measure motor armature current and generate an induced torque signal to said summing means which is proportional thereto, and said acceleration torque sensor includes a differentiator which connects to measure voltage applied to the motor armature circuit windings and which generates an acceleration torque signal to said summing means which is proportional to the first derivative of the measured voltage.
Claim 9
Dependent Claim
151 words
In an electro-mechanical drive system having a d-c electric motor connected to a mechanical load and to a control system, a circuit for generating torque feedback information to the control system, the combination comprising: a steady-state torque feedback circuit connected to indirectly sense the induced torque delivered to the load by the motor and generate a torque feedback signal to said control system when the magnitude of the sensed induced torque exceeds a preset maximum; and a transient torque feedback circuit which includes a differentiator circuit connected to sense the voltage applied to the motor''s stationary windings and generate an acceleration torque signal proportional to the first derivative of that voltage, and a current sensing circuit connected to sense changes in motor armature current and geNerate a signal which is summed with the acceleration torque signal and capacitively coupled to said control system to provide a transient torque feedback signal thereto.
Claim 10
Dependent Claim
151 words
In an electro-mechanical drive system having a d-c electric motor connected to a mechanical load and to a control system, a circuit for generating torque feedback information to the control system, the combination comprising: a steady-state torque feedback circuit connected to indirectly sense the induced torque delivered to the load by the motor and generate a torque feedback signal to said control system when the magnitude of the sensed induced torque exceeds a preset maximum; and a transient torque feedback circuit which includes a differentiator circuit connected to sense the voltage applied to the motor''s stationary windings and generate an acceleration torque signal proportional to the first derivative of that voltage, and a current sensing circuit connected to sense changes in motor armature current and geNerate a signal which is summed with the acceleration torque signal and capacitively coupled to said control system to provide a transient torque feedback signal thereto.
Claim 11
Dependent Claim
40 words
The circuit as recited in claim 6 wherein said transient torque feedback circuit includes a coupling diode connected to block current flow in one direction and to thereby inhibit the generation of a transient torque feedback signal of one polarity.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |