US3590350A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Motor control for skip hoist drive systems and the like
Assignee: Westinghouse Electric Corp
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Filing: 1968-08-30
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Granted: 1971-06-29
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Expires: 1988-08-30
Abstract
Abstract Described is an electrical motor control for skip cars of the type utilized to charge materials into a blast furnace, and for other similar applications, wherein a first current or torque limit of the motor is provided under decelerating conditions and a second and different current or torque limit is provided under accelerating conditions. This tends to equalize the pulling forces in the cables which elevate the skip cars under deceleration and under acceleration conditions and reduces strains in the skip bridge and associated structural elements of the blast furnace.
Inventors
- 👤 William A Munson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 01:25
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/34; H02P7/24; H02P7/28; H02P7/285; H02P7/292; H02P7/293; H02P7/298; H02P7/2985; H02P7/347
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
127 words
In combination, a drive system comprising electrical drive motor means having armature means, speed control means for varying the voltage applied to said drive motor means to thereby vary the speed of said drive motor means, means for sensing the actual current flowing through said armature means, first means operative only under motoring conditions and connected to said sensing means for limiting current flow through said motor means and the output torque of said motor means to a first predetermined maximum value, and second means operative only under regenerating conditions and connected to said sensing means for limiting current flow through said motor means and the output torque of said motor means to a second predetermined maximum value which is lower than said first predetermined maximum valve.
Claim 2
Dependent Claim
127 words
In combination, a drive system comprising electrical drive motor means having armature means, speed control means for varying the voltage applied to said drive motor means to thereby vary the speed of said drive motor means, means for sensing the actual current flowing through said armature means, first means operative only under motoring conditions and connected to said sensing means for limiting current flow through said motor means and the output torque of said motor means to a first predetermined maximum value, and second means operative only under regenerating conditions and connected to said sensing means for limiting current flow through said motor means and the output torque of said motor means to a second predetermined maximum value which is lower than said first predetermined maximum valve.
Claim 3
Dependent Claim
49 words
The combination of claim 1 including a voltage reference controller, a current controller responsive to current through said motor coupled to the output of said voltage reference controller, and means coupled to the output of said current controller for varying the voltage and current supplied to said motor means.
Claim 4
Dependent Claim
21 words
The combination of claim 2 wherein the means coupled to the output of said current controller comprises a thyristor power supply.
Claim 5
Dependent Claim
42 words
The combination of claim 2 wherein the means coupled to the output of said current controller comprises the field winding of a direct current generator, the output of said direct current generator being connected to the input of said drive motor means.
Claim 6
Dependent Claim
73 words
The combination of claim 2, with said first means including a first current limit circuit responsive to current through the motor means under motoring conditions, with said second means including a second current limit circuit responsive to current through the motor means under regenerating conditions, and means connecting the outputs of said first and second current limit circuits to said voltage reference controller to regulate the maximum output of said voltage reference controller.
Claim 7
Dependent Claim
131 words
The combination of claim 1 in further combination with a blast furnace charging system comprising a skip bridge, a pair of skip cars reciprocable on said skip bridge, cable means interconnecting said skip cars, a rotatable winch drum around which said cable is wound whereby rotation of the winch drum will cause one of said skip cars to ascend the skip bridge while the other descends, and means connecting said drive motor means to said winch drum whereby the current through said motor means may be higher during acceleration conditions when a loaded skip car initially ascends the skip bridge than when a skip car decelerates at the top of the skip bridge, thereby minimizing vibrational shocks to said skip bridge as a result of sudden deceleration of the skip cars.
Claim 8
Dependent Claim
76 words
The combination of claim 6 wherein said first means includes a first current limiting cirCuit responsive to current through the motor means when said skip cars accelerate, and wherein said second means includes a second current limiting circuit responsive to current through the motor means when said skip cars decelerate, and means connecting the outputs of said first and second current limiting circuits to said means for varying the voltage applied to said drive motor means.
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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) | 1974-06-28 | 1974-12-28 | 1975-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-28 | 1978-12-28 | 1979-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-28 | 1982-12-28 | 1983-06-29 | $7700.00 | Window Closed / Lapsed |