US4700256A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solid state current limiting circuit interrupter
Assignee: General Electric Co
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Filing: 1986-06-16
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Granted: 1987-10-13
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Expires: 2006-06-16
Abstract
Abstract A solid state current limiting circuit interrupter for the arcless interruption of current through a protected circuit includes a pair of mechanically switched contacts electrically connected in series between the power source and the protected load. A solid state switch becomes electrically connected in parallel across the contacts when the contacts are opened to transfer the current to the solid state switch in a first state of voltage drop lower than arc voltage, and then in a second state of voltage drop higher than power source voltage in which stored energy is dissipated and current is forced to drop to zero to interrupt the circuit.
Inventors
- 👤 Edward K. Howell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:53
CPC Classifications
H; H01; H01H; H01H9/00; H01H9/54; H01H9/541; H01H9/542; H01H2009/543; H01H2009/546
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
296 words
An arrangement for rapidly interrupting load current flow with minimal arcing, comprising: (a) electromechanical switching means having fixed and movable contacts for connection between a source of electric power and a load and constructed to permit extremely rapid separation of said contacts for interrupting load current flow through said contacts; (b) semiconductor switching means comprising first and second primary electrodes and a control electrode; (c) first means for switching on said semiconductor switching means and transferring load current away from said contacts, through said semiconductor switching means substantially instantly upon initial separation of said contacts and for thereafter maintaining said semiconductor switching means fully conductive for an interval sufficient to provide for de-ionization of any arc between said contacts and for sufficiently cooling and separating said contacts to permit reapplication of a voltage across said contacts which is greater than the voltage of the source of electric power, said interval being in the order or approximately 100 microseconds; (d) said first means comprising: (1) saturable transformer means having a primary winding, a secondary winding and a saturable core; (2) said primary winding being coupled in series circuit with said first and second primary electrodes across said contacts; and (3) said secondary winding being coupled between said control electrode and one of said first and second primary electrodes for turning on said solid state switching means responsive to the voltage created across said contacts upon their initial separation and for turning off said solid state switching means upon saturation of said saturable core; and (e) voltage responsive means connected in circuit across said contacts for transferring load current subsequent to turn off of said solid state switching means and subsequent to the voltage across said voltage responsive means exceeding the voltage of said source of electric power.
Claim 2
Dependent Claim
296 words
An arrangement for rapidly interrupting load current flow with minimal arcing, comprising: (a) electromechanical switching means having fixed and movable contacts for connection between a source of electric power and a load and constructed to permit extremely rapid separation of said contacts for interrupting load current flow through said contacts; (b) semiconductor switching means comprising first and second primary electrodes and a control electrode; (c) first means for switching on said semiconductor switching means and transferring load current away from said contacts, through said semiconductor switching means substantially instantly upon initial separation of said contacts and for thereafter maintaining said semiconductor switching means fully conductive for an interval sufficient to provide for de-ionization of any arc between said contacts and for sufficiently cooling and separating said contacts to permit reapplication of a voltage across said contacts which is greater than the voltage of the source of electric power, said interval being in the order or approximately 100 microseconds; (d) said first means comprising: (1) saturable transformer means having a primary winding, a secondary winding and a saturable core; (2) said primary winding being coupled in series circuit with said first and second primary electrodes across said contacts; and (3) said secondary winding being coupled between said control electrode and one of said first and second primary electrodes for turning on said solid state switching means responsive to the voltage created across said contacts upon their initial separation and for turning off said solid state switching means upon saturation of said saturable core; and (e) voltage responsive means connected in circuit across said contacts for transferring load current subsequent to turn off of said solid state switching means and subsequent to the voltage across said voltage responsive means exceeding the voltage of said source of electric power.
Claim 3
Dependent Claim
50 words
The arrangement of claim 1 wherein said solid state switching means comprises at least one transistor, said first and second primary electrodes comprise a collector and emitter and said control electrode comprises a base electrode of said at least one transistor, and wherein said voltage responsive means comprises a varistor.
Claim 4
Dependent Claim
19 words
The arrangement of claim 2 wherein said secondary winding is coupled between said base electrode and said emitter electrode.
Claim 5
Dependent Claim
42 words
The solid state circuit interrupter of claim 3 further including a Zener diode connected between a collector of said transistor and said transistor base for providing initial voltage for turning on said transistor when said fixed and movable contacts first become separated.
References Cited (Backward Citations)
US3558910A
Cited
US3543047A
Cited
US4001742A
Cited
US4115829A
Cited
US4184128A
Cited
US4420784A
Cited
US4438472A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-10-12 | 1991-04-13 | 1991-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-12 | 1995-04-13 | 1995-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-12 | 1999-04-13 | 1999-10-13 | $7700.00 | Window Closed / Lapsed |