US3854091A
Expired / Lapsed
US
⏱️ 0.0 years remaining
A direct current converter for isolating a measuring transducer from its power source
Assignee: Danfoss AS
•
Filing: 1973-11-15
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Granted: 1974-12-10
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Expires: 1993-11-15
Abstract
Abstract A direct-current converter, for isolating a measuring transducer from its power source, comprises a magnetic core with primary, secondary and sensor windings. Additionally an energizing winding is provided periodically to change the magnetic inductance of the core, by developing a magnetic field at right angles to that of the other three windings.
Inventors
- 👤 O Knudsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 02:55
CPC Classifications
G; G08; G08C; G08C19/00; G08C19/02; H; H03; H03F; H03F3/00; H03F3/38; H03F3/387
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
159 words
A direct-current converter suitable for electrically isolating a measuring transducer from the power source for the measuring transducer, the converter comprising: a magnetic core; a primary winding on said core; a secondary winding on said core; means for supplying respective substantially constant direct currents to said primary and secondary windings; a sensor winding on said core in which sensor winding a control voltage is developed when a difference occurs between the magnetic flux due to currents in said primary and said secondary winding respectively; a regulator for adjusting said direct current supplied to said secondary winding in dependence upon said control voltage such that said magnetic flux difference tends to zero; an energising winding for developing in said core a magnetic field at right angles to magnetic fields associated with said primary, secondary and sensor winding; and means for supplying an energising current to said energising winding for periodically changing the magnitude of the magnetic induction of said core.
Claim 2
Dependent Claim
159 words
A direct-current converter suitable for electrically isolating a measuring transducer from the power source for the measuring transducer, the converter comprising: a magnetic core; a primary winding on said core; a secondary winding on said core; means for supplying respective substantially constant direct currents to said primary and secondary windings; a sensor winding on said core in which sensor winding a control voltage is developed when a difference occurs between the magnetic flux due to currents in said primary and said secondary winding respectively; a regulator for adjusting said direct current supplied to said secondary winding in dependence upon said control voltage such that said magnetic flux difference tends to zero; an energising winding for developing in said core a magnetic field at right angles to magnetic fields associated with said primary, secondary and sensor winding; and means for supplying an energising current to said energising winding for periodically changing the magnitude of the magnetic induction of said core.
Claim 3
Dependent Claim
47 words
A direct-current converter according to claim 1 wherein said core is a toroid having an internal hollow cavity, said primary, secondary and sensor windings are wound in toroidal form on said core, and said energizing winding is wound in said cavity in the form of a solenoid.
Claim 4
Dependent Claim
19 words
A direct-current converter according to claim 1 wherein said energizing current is formed by a train of direct-current pulses.
Claim 5
Dependent Claim
38 words
A direct-current converter according to claim 3 wherein said means for supplying an energizing current comprises means for supplying a direct-current voltage to said energising winding, and a periodically actuated electronic switch in parallel with said energising windings.
Claim 6
Dependent Claim
38 words
A direct-current converter according to claim 4 comprising two supply conductors for connecting said secondary winding to said power source and to a measured value indicator, and wherein the entire operating current is passed through said secondary winding.
Claim 7
Dependent Claim
65 words
A direct-current converter according to claim 4 comprising an alternating current amplifier having an input connected to said sensor winding, and an output; a demodulator having an input connected to said output of said amplifier and an output from which a signal is supplied to said regulator; and an oscillator which in use supplies a signal to control said switch and said demodulator in synchronism.
Claim 8
Dependent Claim
92 words
A direct-current converter according to claim 1 comprising a measurinG transducer, a power source for the measuring transducer, a transformer having a first and a second winding, an oscillator having an input and an output, and a rectifier; said power source being connected to said secondary winding and to said input of said oscillator, said output of said oscillator being connected to said first winding of said transformer, and said second winding of said transformer being connected to said rectifier which is connected in series with said transducer and said primary winding.
Claim 9
Dependent Claim
30 words
A direct-current converter according to claim 7 comprising an electronic switch in parallel with said energizing winding, said oscillator being in series with the parallel-connected electronic switch and energising winding.
Claim 10
Dependent Claim
56 words
A direct-current converter according to claim 1 comprising a measuring transducer, a power source for the measuring transducer, said power source having two output conductors, one of which is connected to said secondary winding, and a constant-current regulator and constant-voltage element connected in series between the other output conductor of said power source and said regulator.
Claim 11
Dependent Claim
18 words
A direct-current converter according to claim 1 comprising a Zener diode connected in parallel with said energizing winding.
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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) | 1977-12-09 | 1978-06-10 | 1978-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-09 | 1982-06-10 | 1982-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-09 | 1986-06-10 | 1986-12-10 | $7700.00 | Window Closed / Lapsed |