US3671816A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Time delay control system for directional relays with electrical interlock
Assignee: Cutler Hammer Inc
•
Filing: 1970-05-21
•
Granted: 1972-06-20
•
Expires: 1990-05-21
Abstract
Abstract A solid state control circuit for completing selectively energizing circuits for the operating coils of directional relays in a motor control system which affords a predetermined time delay on energization for each relay, and electrical lockout against simultaneous energization of one relay operating coil while the other remains energized and vice versa.
Inventors
- 👤 Gerald R Ritzow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:59
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/28; H02; H02P; H02P23/00; H02P23/24
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
177 words
The combination with a source of D.C. voltage supply and a pair of electromagnetic relays or the like, of a pair transistors each having its collector-emitter circuit connected in series with the operating winding of an individual one of said relays to one side of said source, like R/C circuits each of which is connected to said one side of said source and each being connected in circuit with the base of a transistor individual thereto, switch means operable to complete energizing connections from said source through each of said associated R/C and transistorrelay operating circuits selectively to afford tiMe delay energization of a selected relay operating winding, and electrical interlock means comprising like means each of which is in circuit with an R/C circuit individual thereto and the collector of the transistor whose base is not in circuit with such R/C circuit, each of said last mentioned means acting when the transistor with whose collector it is connected is conducting to prevent the R/C circuit with which it is connected from rendering the other transistor conducting.
Claim 2
Dependent Claim
177 words
The combination with a source of D.C. voltage supply and a pair of electromagnetic relays or the like, of a pair transistors each having its collector-emitter circuit connected in series with the operating winding of an individual one of said relays to one side of said source, like R/C circuits each of which is connected to said one side of said source and each being connected in circuit with the base of a transistor individual thereto, switch means operable to complete energizing connections from said source through each of said associated R/C and transistorrelay operating circuits selectively to afford tiMe delay energization of a selected relay operating winding, and electrical interlock means comprising like means each of which is in circuit with an R/C circuit individual thereto and the collector of the transistor whose base is not in circuit with such R/C circuit, each of said last mentioned means acting when the transistor with whose collector it is connected is conducting to prevent the R/C circuit with which it is connected from rendering the other transistor conducting.
Claim 3
Dependent Claim
40 words
The combination according to claim 1 wherein said R/C circuits each comprise a resistor and capacitor connected in series and a zener diode connected between the base of its associated transistor and the junction between said resistor and said capacitor.
Claim 4
Dependent Claim
54 words
The combination according to claim 2 wherein said like means of said interlock means each comprises a half-wave rectifier connected to permit current flow from the junction of the resistor and capacitor of an R/C circuit to the collector of the transistor not associated with said R/C circuit but not in the reverse direction.
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) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |