Patent US3601657A successfully refreshed from Google Patents.
US3601657A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Overvoltage protective device
Assignee: Avco Corp
•
Filing: 1968-10-31
•
Granted: 1971-08-24
•
Expires: 1988-10-31
Abstract
Abstract A high voltage, high current, short circuiting device which can sense a condition overvoltage at the output of a magnetohydrodynamic generator or the like and initiate a short circuit in microseconds. The device incorporates a high voltage, high current ignitron actuated by a voltage sensing circuit; a spring-loaded switch to assist the ignitron in carrying the short circuit current; a spark gap as back up for the ignitron; and a bistable relay for use in combination with the spring-loaded switch and to actuate auxiliary apparatus such as fuel cutoff valves and the like.
Inventors
- 👤 Henry R Guarino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:28
CPC Classifications
H; H02; H02H; H02H7/00; H02H3/00; H02H3/02; H02H3/021; H02H3/023; H02H3/04; H02H3/044
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
133 words
In magnetohydrodynamic apparatus having terminal electrodes and operative with a flow of electrically conductive working fluid through a magnetic field, the combination comprising: a. ignitron means connected across said terminal electrodes for short circuiting said terminal electrodes; b. voltage sensing means coupled to said terminal electrodes for actuating said ignitron means when the voltage at said terminal electrodes reaches a first predetermined value; c. mechanically actuated switch means connected across said terminal electrodes for short circuiting said terminal electrodes; d. means operative upon a short circuit of said terminal electrodes by said ignitron means for actuating said switch means; and e. spark gap means connected across said terminal electrodes for short circuiting said terminal electrodes when the voltage at said terminal electrodes reaches a second predetermined voltage greater than said first predetermined voltage.
Claim 2
Dependent Claim
133 words
In magnetohydrodynamic apparatus having terminal electrodes and operative with a flow of electrically conductive working fluid through a magnetic field, the combination comprising: a. ignitron means connected across said terminal electrodes for short circuiting said terminal electrodes; b. voltage sensing means coupled to said terminal electrodes for actuating said ignitron means when the voltage at said terminal electrodes reaches a first predetermined value; c. mechanically actuated switch means connected across said terminal electrodes for short circuiting said terminal electrodes; d. means operative upon a short circuit of said terminal electrodes by said ignitron means for actuating said switch means; and e. spark gap means connected across said terminal electrodes for short circuiting said terminal electrodes when the voltage at said terminal electrodes reaches a second predetermined voltage greater than said first predetermined voltage.
Claim 3
Dependent Claim
34 words
The combination as defined in claim 1 and additionally including means connected across said terminal electrodes for providing a predetermined rate or rise of voltage over a finite time period at said terminal electrodes.
Claim 4
Dependent Claim
35 words
The combination as defined in claim 2 wherein said voltage sensing means actuates said ignitron to short circuit said terminal electrodes before the voltage at said terminal electrodes substantially increases over said first predetermined value.
Claim 5
Dependent Claim
27 words
The combination as defined in claim 3 wherein said voltage sensing means includes input means comprising a frequency compensated voltage divider circuit connected across said terminal electrodes.
Claim 6
Dependent Claim
61 words
The combination as defined in claim 4 wherein said voltage divider circuit is comprised of first and second resistor means connected in parallel with respectively first and second capacitor means, the ratio of said capacitor means being substantially the inverse of the ratio of said resistor means to provide an output signal across said second resistor and said second capacitor means.
Claim 7
Dependent Claim
119 words
In magnetohydrodynamic apparatus having terminal electrodes and operative with a flow of electrically conductive working fluid through a magnetic field, the combination comprising: a. ignitron means connected across said terminal electrodes for short circuiting same, said ignitron means having a trigger input signal terminal; b. voltage sensing means coupled between said terminal electrodes and said trigger input terminal for triggering said ignitron means to short circuit said terminal electrodes when the voltage at said terminal electrodes increases from its normal value to a first predetermined value; c. switch means connected across said terminal electrodes for short circuiting same; and d. means operative upon a short circuit of said terminal electrodes by said ignitron means for actuating said switch means.
Claim 8
Dependent Claim
119 words
In magnetohydrodynamic apparatus having terminal electrodes and operative with a flow of electrically conductive working fluid through a magnetic field, the combination comprising: a. ignitron means connected across said terminal electrodes for short circuiting same, said ignitron means having a trigger input signal terminal; b. voltage sensing means coupled between said terminal electrodes and said trigger input terminal for triggering said ignitron means to short circuit said terminal electrodes when the voltage at said terminal electrodes increases from its normal value to a first predetermined value; c. switch means connected across said terminal electrodes for short circuiting same; and d. means operative upon a short circuit of said terminal electrodes by said ignitron means for actuating said switch means.
Claim 9
Dependent Claim
72 words
The combination as defined in claim 6 wherein said voltage sensing means includes a frequency compensated voltage divider circuit for providing a signal proportional to said first predetermined value in not less than about 2 microseconds and more than 1 millisecond; and additionally incluDing capacitor means connected across said terminal electrodes for providing a substantially exponential rate of rise of voltage at said terminal electrodes prior to actuation of said ignitron means.
Claim 10
Dependent Claim
102 words
In apparatus for protecting devices subject to overvoltage conditions and having first terminals at which said voltage appears, the combination comprising: a. ignitron means having second terminals adapted for connection across said first terminals for short circuiting same; b. voltage sensing means coupled to said second terminals for actuating said ignitron means when the voltage at said first terminals increases over its normal value to a first predetermined value; c. switch means connected across said second terminals for short circuiting same; and d. means operative upon a short circuit of said second terminals by said ignitron means for actuating said switch means.
Claim 11
Dependent Claim
102 words
In apparatus for protecting devices subject to overvoltage conditions and having first terminals at which said voltage appears, the combination comprising: a. ignitron means having second terminals adapted for connection across said first terminals for short circuiting same; b. voltage sensing means coupled to said second terminals for actuating said ignitron means when the voltage at said first terminals increases over its normal value to a first predetermined value; c. switch means connected across said second terminals for short circuiting same; and d. means operative upon a short circuit of said second terminals by said ignitron means for actuating said switch means.
Claim 12
Dependent Claim
136 words
In apparatus for protecting devices subject to overvoltage conditions and having first terminals at which said voltage appears, the combination comprising: a. ignitron means having second terminals adapted for connection across said first terminals for short circuiting said first terminals; b. voltage sensing means coupled to said second terminals for actuating said ignitron means when the voltage at said first terminals reaches a first predetermined value; c. mechanically actuated switch means connected across said second terminals for short circuiting said second terminals; d. means operative upon a short circuit of said second terminals by said ignitron means for actuating said switch means; and e. spark gap means connected across said second terminals for short circuiting said second terminals when the voltage at said second terminals reaches a second predetermined voltage greater than said first predetermined voltage.
Claim 13
Dependent Claim
136 words
In apparatus for protecting devices subject to overvoltage conditions and having first terminals at which said voltage appears, the combination comprising: a. ignitron means having second terminals adapted for connection across said first terminals for short circuiting said first terminals; b. voltage sensing means coupled to said second terminals for actuating said ignitron means when the voltage at said first terminals reaches a first predetermined value; c. mechanically actuated switch means connected across said second terminals for short circuiting said second terminals; d. means operative upon a short circuit of said second terminals by said ignitron means for actuating said switch means; and e. spark gap means connected across said second terminals for short circuiting said second terminals when the voltage at said second terminals reaches a second predetermined voltage greater than said first predetermined voltage.
Claim 14
Dependent Claim
28 words
The combination as defined in claim 9 and additionally including means connected across said second terminals for providing a predetermined rate of rise of voltage at said terminals.
Claim 15
Dependent Claim
27 words
The combination as defined in claim 10 wherein said voltage sensing means includes input means comprising a frequency compensated voltage divider circuit connected across said second terminals.
References Cited (Backward Citations)
US2735963A
Cited
DE681392C
Cited
US2925548A
Cited
US3049632A
Cited
US3182213A
Cited
US3418530A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-23 | 1975-02-22 | 1975-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-23 | 1979-02-22 | 1979-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-23 | 1983-02-22 | 1983-08-24 | $7700.00 | Window Closed / Lapsed |