Patent US3090901A successfully refreshed from Google Patents.
US3090901A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Motor speed control systems
Assignee: English Electric Co Ltd
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Filing: 1960-06-07
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Granted: 1963-05-21
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Expires: 1980-06-07
Abstract
No abstract record available.
Inventors
- 👤 Shaw Norman Harry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:32
CPC Classifications
H; H02; H02P; H02P25/00; H02P25/16; H02P25/28
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
130 words
A SPEED CONTROL SYSTEM FOR AN ALTERNATING CURRENT ELECTRIC INDUCTION MOTOR HAVING A SQUIRREL CAGE ROTOR AND A STATOR HAVING RUNNING WINDING MEANS AND BRAKING WINDING MEANS, COMPRISING IN COMBINATION, SPEED DETERMINING VARIABLE IMPEDANCE MEANS IN THE ELECTRIC POWER SUPPLY CIRCUIT TO SAID MOTOR, FIRST CONTROL MEANS FOR PREDETERMINING THE EFFECTIVE IMPEDANCE OF SAID IMPEDANCE MEANS, AND SECOIND CONTROL MEANS RESPONSIVE TO THE SPEED OF THE MOTOR FOR AUTOMATICALLY VARYING THE THE SAID EFFECTIVE IMPEDANCE OF SAID IMPEDANCE MEANS IN A CORRECTIVE SENSE IN ACCORDANCE WITH A NEGATIVE SPEED ERROR OF THE MOTOR SPEED AND FOR SIMULTANEOUSLY ENERGIZING SAID BRAKING WINDING AND AUTOMATICALLY ALTERING THE EFFECTIVE IMPEDANCE OF SAID IMPEDANCE MEANS TO SUCH A VALUE THAT THE MOTOR IS SUBSTANTIALLY DE-ENERGIZED IF THE SPEED ERROR OF THE MOTOR BECOMES POSITIVE.
Claim 2
Dependent Claim
130 words
A SPEED CONTROL SYSTEM FOR AN ALTERNATING CURRENT ELECTRIC INDUCTION MOTOR HAVING A SQUIRREL CAGE ROTOR AND A STATOR HAVING RUNNING WINDING MEANS AND BRAKING WINDING MEANS, COMPRISING IN COMBINATION, SPEED DETERMINING VARIABLE IMPEDANCE MEANS IN THE ELECTRIC POWER SUPPLY CIRCUIT TO SAID MOTOR, FIRST CONTROL MEANS FOR PREDETERMINING THE EFFECTIVE IMPEDANCE OF SAID IMPEDANCE MEANS, AND SECOIND CONTROL MEANS RESPONSIVE TO THE SPEED OF THE MOTOR FOR AUTOMATICALLY VARYING THE THE SAID EFFECTIVE IMPEDANCE OF SAID IMPEDANCE MEANS IN A CORRECTIVE SENSE IN ACCORDANCE WITH A NEGATIVE SPEED ERROR OF THE MOTOR SPEED AND FOR SIMULTANEOUSLY ENERGIZING SAID BRAKING WINDING AND AUTOMATICALLY ALTERING THE EFFECTIVE IMPEDANCE OF SAID IMPEDANCE MEANS TO SUCH A VALUE THAT THE MOTOR IS SUBSTANTIALLY DE-ENERGIZED IF THE SPEED ERROR OF THE MOTOR BECOMES POSITIVE.
References Cited (Backward Citations)
GB677358A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1966-05-20 | 1966-11-19 | 1967-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1970-05-20 | 1970-11-19 | 1971-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1974-05-20 | 1974-11-19 | 1975-05-21 | $7700.00 | Window Closed / Lapsed |