Patent US4242712A successfully refreshed from Google Patents.
US4242712A
Expired / Lapsed
US
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Over-power safety device for motor driven system
Assignee: Wells Fargo Bank Minnesota NA
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Filing: 1978-10-12
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Granted: 1980-12-30
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Expires: 1998-10-12
Abstract
Abstract A safety device and method for detecting over-power conditions on the chassis of a motor driven system interrupts energization of the system when the voltage differential between the system chassis and earth ground exceeds a selected value. The device is especially beneficial for systems utilizing multi-phase induction motors in which current sensing safety devices cannot effectively detect all over-power conditions. The safety device utilizes a fuse and a motor control relay such that, upon the occurrence of the over-power condition, the fuse is rendered non-conductive, opening the motor control relay.
Inventors
- 👤 Joseph D. Doll
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:29
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/14
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
112 words
A safety device for detecting a fault condition on a chassis of a motor driven system and for interrupting operation of the system upon the occurrence of said condition, said system having means responsive to a control signal for selectively deenergizing the system, said safety device comprising: a. a first connection to earth ground; b. a second connection to earth ground spaced from said first connection; c. a connector between said first connection and said chassis of said system; and d. a signal generator connected to said second connection and to said chassis for generating the control signal when the voltage between the chassis and the second connection exceeds a selected value.
Claim 2
Dependent Claim
112 words
A safety device for detecting a fault condition on a chassis of a motor driven system and for interrupting operation of the system upon the occurrence of said condition, said system having means responsive to a control signal for selectively deenergizing the system, said safety device comprising: a. a first connection to earth ground; b. a second connection to earth ground spaced from said first connection; c. a connector between said first connection and said chassis of said system; and d. a signal generator connected to said second connection and to said chassis for generating the control signal when the voltage between the chassis and the second connection exceeds a selected value.
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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) | 1983-12-30 | 1984-06-30 | 1984-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-30 | 1988-06-30 | 1988-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-30 | 1992-06-30 | 1992-12-30 | $7700.00 | Window Closed / Lapsed |