Patent US3611093A successfully refreshed from Google Patents.
US3611093A
Expired / Lapsed
US
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High-speed current reversal system
Assignee: Westinghouse Electric Corp
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Filing: 1970-03-25
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Granted: 1971-10-05
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Expires: 1990-03-25
Abstract
Abstract A high-speed current reversal system and method wherein the current through an impedance element including inductance, such as the field winding of a DC motor, may be rapidly reversed as compared to the normal reversal time required by reversing the polarities of the power supply, the rapid reversal being effected by open circuiting the impedance element in the direction of current flow, establishing a resonant oscillation at a predetermined resonant frequency, for example, so that the half period at the resonant frequency is equal to the desired rapid reversal time, translating the current in the reverse direction back to the source when it reaches a predetermined magnitude, reversing the polarity of the power supply to sustain the reverse direction of current flow and reclosing the open circuit prior to the time of the next current reversal.
Inventors
- 👤 Alec H B Walker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:07
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/282
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
201 words
A system for rapidly reversing the direction of current through a load including inductance and operative with a power supply providing respective outputs of opposite polarities the combination of: reversing means for reversing the polarity of said outputs within a first time period; bidirectional switch means operatively connected between said power supply and said impedance element for translating current to said load in either direction in accordance with the respective polarity of said outputs; capacitive means operatively connected across said load forming a resonant circuit with the inductance thereof and having a predetermined resonant frequency; and means for instigating the rapid reversal of current through said load in a second time period shorter than said first period by open circuiting said bidirectional switch means in the direction of current flow so that said resonant circuit resonates causing a reversal of the current which is then translated by said bidirectional switch means in the opposite direction to the previous direction of current flow when the current reaches a predetermined magnitude in said opposite direction, and for closing said bidirectional switch means in the direction previously open circuited at a time prior to the time of the next reversal of current is desired.
Claim 2
Independent Claim
201 words
A system for rapidly reversing the direction of current through a load including inductance and operative with a power supply providing respective outputs of opposite polarities the combination of: reversing means for reversing the polarity of said outputs within a first time period; bidirectional switch means operatively connected between said power supply and said impedance element for translating current to said load in either direction in accordance with the respective polarity of said outputs; capacitive means operatively connected across said load forming a resonant circuit with the inductance thereof and having a predetermined resonant frequency; and means for instigating the rapid reversal of current through said load in a second time period shorter than said first period by open circuiting said bidirectional switch means in the direction of current flow so that said resonant circuit resonates causing a reversal of the current which is then translated by said bidirectional switch means in the opposite direction to the previous direction of current flow when the current reaches a predetermined magnitude in said opposite direction, and for closing said bidirectional switch means in the direction previously open circuited at a time prior to the time of the next reversal of current is desired.
Claim 3
Dependent Claim
31 words
The combination of claim 1 wherein: said capacitance means is so selected to provide said resonant frequency having a half period related to the time desired for reversing the current flow.
Claim 4
Dependent Claim
22 words
The combination of claim 2 wherein: said time desired for reversing is substantially equal to the half period of said resonant frequency.
Claim 5
Dependent Claim
59 words
The combination of claim 1 wherein: said load comprises the field winding of a DC motor, and said bidirectional switch means includes a first unidirectional switch for translating current in one direction and a second unidirectional switch for translating current in the other direction, each of said switches being operative to be open circuited when current is flowing therethrough.
Claim 6
Dependent Claim
20 words
The combination of claim 4 wherein: said first and second unidirectional switches each comprise switching devices having a turnoff characteristic.
Claim 7
Dependent Claim
106 words
In a method for rapidly reversing the direction of current through a load including inductance comprising the steps of: providing current from a source to said load in either direction; open circuiting the current in the direction of flow; establishing a resonant oscillation with said impedance element so that the current reverses to a predetermined value in a predetermined time; translating the current in the reverse direction when it reaches said predetermined value back to the source; reversing the polarity of the source to sustain the current flow in the reverse direction; and closing the previously opened circuit prior to the next reversal of current direction.
Claim 8
Dependent Claim
106 words
In a method for rapidly reversing the direction of current through a load including inductance comprising the steps of: providing current from a source to said load in either direction; open circuiting the current in the direction of flow; establishing a resonant oscillation with said impedance element so that the current reverses to a predetermined value in a predetermined time; translating the current in the reverse direction when it reaches said predetermined value back to the source; reversing the polarity of the source to sustain the current flow in the reverse direction; and closing the previously opened circuit prior to the next reversal of current direction.
Claim 9
Dependent Claim
27 words
The method of claim 6 wherein: said predetermined time is substantially less than the time required to reverse the current by reversing the polarity of the source.
Claim 10
Dependent Claim
23 words
The method of claim 7 wherein: said resonant oscillation has a frequency having a half period substantially equal to said predetermined time period.
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) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |