USRE28517E
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filter-to-line transient isolator
Assignee: —
•
Filing: 1974-07-01
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Granted: 1975-08-12
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Expires: 1994-07-01
Abstract
Abstract A device serially coupled between a wayside power source and the input filter of a chopper or inverter propulsion circuit, for attenuating the rate of charge and discharge of input filter capacitors to the wayside power source during the respective application and interruption of power to the input circuit. A saturable reactor in parallel with a resistor effectively switches the resistance into the circuit to impede current flow during periods of current in-rush or out-rush, and out of the circuit during periods of normal current flow.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:31
CPC Classifications
H; H02; H02M; H02M1/00; H02M1/32; B; B60; B60L; B60L9/00; H02H; H02H9/00; H02H9/005; B60L2200/00; B60L2200/26
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
276 words
An improved protective circuit for limiting a line in-rush and out-rush of current from a propulsion system input filter, wherein the current flow between a DC power source and the filter is selectively attenuated and alternatively unattenuated to enable drawing power without a loss, wherein the improvement comprises: a. a static power conversion unit for converting direct current from the DC power source (into alternating current;) b. a filter connected between said power conversion unit and said DC power source for filtering the ripple voltage from said power conversion unit and ripple current from said DC power source, said filter comprising at least one capacitor in parallel with said power conversion unit and at least one reactor in series with said power conversion unit and power source, said reactor having both a saturable core portion and a non-saturable core portion; and c. means for occasionally and alternately charging and discharging said capacitor through said reactor; wherein said reactor is so constructed that during periods of charging of said capacitor the flux in said saturable core portion moves toward a condition of positive saturation and during periods of discharging of said capacitor (and ) the flux therein moves toward a condition of negative saturation, thereby providing during these periods an inductive reactance to substantially attenuate the current flow through said saturable core portion, whereas during periods of steady state current in-flow, subsequent to the charging of said capacitor, said saturable core portion remains saturated to allow for the substantially unimpeded flow of current therethrough, and said non-saturable core portion offers a relatively small fixed reactance, which combines with that of said capacitor to perform the filtering function.
Claim 2
Dependent Claim
276 words
An improved protective circuit for limiting a line in-rush and out-rush of current from a propulsion system input filter, wherein the current flow between a DC power source and the filter is selectively attenuated and alternatively unattenuated to enable drawing power without a loss, wherein the improvement comprises: a. a static power conversion unit for converting direct current from the DC power source (into alternating current;) b. a filter connected between said power conversion unit and said DC power source for filtering the ripple voltage from said power conversion unit and ripple current from said DC power source, said filter comprising at least one capacitor in parallel with said power conversion unit and at least one reactor in series with said power conversion unit and power source, said reactor having both a saturable core portion and a non-saturable core portion; and c. means for occasionally and alternately charging and discharging said capacitor through said reactor; wherein said reactor is so constructed that during periods of charging of said capacitor the flux in said saturable core portion moves toward a condition of positive saturation and during periods of discharging of said capacitor (and ) the flux therein moves toward a condition of negative saturation, thereby providing during these periods an inductive reactance to substantially attenuate the current flow through said saturable core portion, whereas during periods of steady state current in-flow, subsequent to the charging of said capacitor, said saturable core portion remains saturated to allow for the substantially unimpeded flow of current therethrough, and said non-saturable core portion offers a relatively small fixed reactance, which combines with that of said capacitor to perform the filtering function.
Claim 3
Dependent Claim
57 words
A protective circuit as set forth in claim 1 and including an impedance element connected in parallel with said reactor, the impedance of said impedance element being of a magnitude such that during periods of charging and discharging of said capacitor the current flow is directed from said saturable core portion to flow through said impedance element.
Claim 4
Dependent Claim
19 words
A protective circuit as set forth in claim 1 wherein said non-saturable corE portion comprises an air core reactor.
Claim 5
Dependent Claim
96 words
A protective circuit as set forth in claim 1 wherein said charging and discharging means includes: a. a current limiting controlled conductive means coupled in series between a first point intermediate said power source and said reactor and a second point on the return side of said capacitor, said conductive means adapted to be non-conductive during normal operation of the propulsion system and to conduct current subsequent to the shutdown thereof, to discharge said filter capacitor toward said power supply and thereby cause the flux of said reactor to move toward a condition of negative saturation.
Claim 6
Dependent Claim
245 words
A protection circuit for limiting current flow between a power source and a capacitor filter during periods of charge and discharge of the filter capacitor comprising: a. a DC power source; b. a static power conversion unit connected thereto for converting direct current from said DC power source (into alternating current;) c. a capacitor connected in parallel with said power conversion unit for filtering the ripple voltage therefrom; d. a reactor coupled in series between said DC power source and said capacitor, said reactor comprising a non-saturable core portion for filtering ripple current from said DC power source and ripple voltage from said power conversion unit, and a saturable core portion; and e. means for occasionally and alternately charging and discharging said capacitor through said reactor; wherein said reactor is so constructed that during periods of charging of said capacitor, the flux in said saturable core portion moves toward a condition of positive saturation and during periods of discharging of said capacitor the flux therein moves toward a condition of negative saturation, thereby providing during these periods an inductive reactance to substantially attenuate the current flow through said saturable core portion, whereas during periods of steady state current inflow, subsequent to the charging of said capacitor, said saturable core portion remains saturated to allow for the substantially unimpeded flow of current therethrough; and said non-saturable core portion offers a relatively small fixed reactance, which combines with that of said capacitor to perform the filtering function.
Claim 7
Dependent Claim
245 words
A protection circuit for limiting current flow between a power source and a capacitor filter during periods of charge and discharge of the filter capacitor comprising: a. a DC power source; b. a static power conversion unit connected thereto for converting direct current from said DC power source (into alternating current;) c. a capacitor connected in parallel with said power conversion unit for filtering the ripple voltage therefrom; d. a reactor coupled in series between said DC power source and said capacitor, said reactor comprising a non-saturable core portion for filtering ripple current from said DC power source and ripple voltage from said power conversion unit, and a saturable core portion; and e. means for occasionally and alternately charging and discharging said capacitor through said reactor; wherein said reactor is so constructed that during periods of charging of said capacitor, the flux in said saturable core portion moves toward a condition of positive saturation and during periods of discharging of said capacitor the flux therein moves toward a condition of negative saturation, thereby providing during these periods an inductive reactance to substantially attenuate the current flow through said saturable core portion, whereas during periods of steady state current inflow, subsequent to the charging of said capacitor, said saturable core portion remains saturated to allow for the substantially unimpeded flow of current therethrough; and said non-saturable core portion offers a relatively small fixed reactance, which combines with that of said capacitor to perform the filtering function.
Claim 8
Dependent Claim
38 words
A protective circuit as set forth in claim 5 and including an impedance connected in parallel with said reactor element for attenuating current flow directed from said reactor element during periods of charging and discharging of said capacitor.
Claim 9
Dependent Claim
19 words
A protective circuit as set forth in claim 5 wherein said non-saturable core portion comprises an air core reactor.
Claim 10
Dependent Claim
96 words
A protective circuit as set forth in claim 5 wherein said charging and discharging means includes: a. a current limiting controlled conductive means coupled in series between a first point intermediate said power source and said reactor and a second point on the return side of said capacitor, said conductive means adapted to be non-conductive during normal operation of the propulsion system and to conduct current subsequent to the shutdown thereof, to discharge said filter capacitor toward said power supply and thereby cause the flux of said reactor to move toward a condition of negative saturation.
References Cited (Backward Citations)
US1287244A
Cited
US3323017A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-11 | 1979-02-10 | 1979-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-11 | 1983-02-10 | 1983-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-11 | 1987-02-10 | 1987-08-12 | $7700.00 | Window Closed / Lapsed |