US3603864A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current dependent filter inductance
Assignee: National Aeronautics and Space Administration
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Filing: 1969-12-31
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Granted: 1971-09-07
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Expires: 1989-12-31
Abstract
Abstract A current dependent variable inductance having a winding and flux coupled magnetic core portion with cross-sectional areas that vary between maximum and minimum values in planes perpendicular to the flux path. Current flow of greater than a given magnitude in the winding causes saturation of the minimum core area and generation of fringing flux in an adjacent auxiliary airgap. The lengths of the fringing flux lines and accordingly of the auxiliary airgap vary directly with the saturation current in the winding. Thus, the value of inductance provided by the winding varies inversely with that current.
Inventors
- 👤 Sherwood Thaler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:38
CPC Classifications
H; H01; H01F; H01F37/00; H01F21/00; H01F21/02; H01F21/08; H01F29/00; H01F29/14; H01F29/143
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
203 words
An electrical inductance comprising: a magnetic core having a pair of spaced-apart pole forces defining an airgap; an elongated spool-shaped auxiliary magnetic core section separate from said magnetic core and disposed in said airgap to provide a pair of primary airgaps as defined between said pole faces and the ends of said elongate auxiliary magnetic core section, said magnetic core with said magnetic core section and said primary airgaps providing a magnetic flux path; auxiliary airgap means defined by said auxiliary magnetic core section with the cross-sectional areas of said magnetic core section residing in planes perpendicular to the flux path varying between a maximum value at its end to a minimum value intermediate its ends with the annular volume surrounding the spool-shaped core section constituting an auxiliary airgap in series with said primary airgaps; a winding on said magnetic core with terminals adapted for connection in an electrical circuit; said minimum value of cross-sectional area selected to saturate at magnetic flux levels produced in said flux path by electrical currents in said winding above a given value so as to generate fringe flux in said auxiliary gap in direct dependence upon the values of current in said winding above said given value.
Claim 2
Dependent Claim
203 words
An electrical inductance comprising: a magnetic core having a pair of spaced-apart pole forces defining an airgap; an elongated spool-shaped auxiliary magnetic core section separate from said magnetic core and disposed in said airgap to provide a pair of primary airgaps as defined between said pole faces and the ends of said elongate auxiliary magnetic core section, said magnetic core with said magnetic core section and said primary airgaps providing a magnetic flux path; auxiliary airgap means defined by said auxiliary magnetic core section with the cross-sectional areas of said magnetic core section residing in planes perpendicular to the flux path varying between a maximum value at its end to a minimum value intermediate its ends with the annular volume surrounding the spool-shaped core section constituting an auxiliary airgap in series with said primary airgaps; a winding on said magnetic core with terminals adapted for connection in an electrical circuit; said minimum value of cross-sectional area selected to saturate at magnetic flux levels produced in said flux path by electrical currents in said winding above a given value so as to generate fringe flux in said auxiliary gap in direct dependence upon the values of current in said winding above said given value.
Claim 3
Dependent Claim
271 words
A power supply comprising: a rectifier means adapted for connection to a source of AC power; a filter means connected to receive the output from said rectifier means; a current-responsive variable inductance means comprised by said filter means, said inductance means comprising; a magnetic core having a pair of spaced-apart pole face defining an airgap; an elongate spool-shaped auxiliary magnetic core section separate from said magnetic core and disposed in said airgap to provide a pair of primary airgaps as defined between said pole faces and the ends of said elongate auxiliary magnetic core section, said magnetic core with said magnetic core section and said primary airgaps providing a magnetic flux path; auxiliary airgap means defined by said auxiliary magnetic core section with the cross-sectional areas of said auxiliary magnetic core section residing in planes perpendicular to the flux path varying between a maximum value at its end to a minimum value intermediate its ends with the annular volume surrounding the spool-shaped core section constituting an auxiliary airgap in series with said primary airgaps; a winding on said magnetic core with terminals adapted for connection in an electrical circuit; said minimum value of cross-sectional area selected to saturate at magnetic flux levels produced in said flux path by electrical currents in said winding above a given value so as to generate fringe flux in said auxiliary airgap in direct dependence upon the value of current in said winding above said given value, said auxiliary airgap means defined by said varying cross-sectional areas providing a variable inductance value which is equal to or greater than the critical inductance of said filter means.
Claim 4
Dependent Claim
271 words
A power supply comprising: a rectifier means adapted for connection to a source of AC power; a filter means connected to receive the output from said rectifier means; a current-responsive variable inductance means comprised by said filter means, said inductance means comprising; a magnetic core having a pair of spaced-apart pole face defining an airgap; an elongate spool-shaped auxiliary magnetic core section separate from said magnetic core and disposed in said airgap to provide a pair of primary airgaps as defined between said pole faces and the ends of said elongate auxiliary magnetic core section, said magnetic core with said magnetic core section and said primary airgaps providing a magnetic flux path; auxiliary airgap means defined by said auxiliary magnetic core section with the cross-sectional areas of said auxiliary magnetic core section residing in planes perpendicular to the flux path varying between a maximum value at its end to a minimum value intermediate its ends with the annular volume surrounding the spool-shaped core section constituting an auxiliary airgap in series with said primary airgaps; a winding on said magnetic core with terminals adapted for connection in an electrical circuit; said minimum value of cross-sectional area selected to saturate at magnetic flux levels produced in said flux path by electrical currents in said winding above a given value so as to generate fringe flux in said auxiliary airgap in direct dependence upon the value of current in said winding above said given value, said auxiliary airgap means defined by said varying cross-sectional areas providing a variable inductance value which is equal to or greater than the critical inductance of said filter means.
Claim 5
Dependent Claim
54 words
The invention as described in claim 1, wherein said auxiliary airgap means defined by said varying cross-sectional areas provides a variable inductance substantially equal to K/I over a predetermined current operating range of said power supply wherein K is a constant and I is the value of DC output current from said filter means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-06 | 1975-03-08 | 1975-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-06 | 1979-03-08 | 1979-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-06 | 1983-03-08 | 1983-09-07 | $7700.00 | Window Closed / Lapsed |