US3816776A
Expired / Lapsed
US
⏱️ 0.0 years remaining
External magnetic field compensator
Assignee: Control Data Corp
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Filing: 1972-12-04
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Granted: 1974-06-11
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Expires: 1992-12-04
Abstract
Abstract An external fluctuating magnetic field may introduce errors in the signal produced by a signal winding, such as may be found in a magnetic transducer, even though the winding may be shielded by a flux shield. The subject of this invention, a compensating winding wound directly around the flux shield, can be made to produce a compensating signal which directly cancels the error component in the signal from the signal winding.
Inventors
- 👤 S Chari
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:47
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/42; G01P3/50; H; H01; H01F; H01F7/00; H01F7/06; H01F7/08; H01F7/18; H02; H02K; H02K41/00; H02K41/02; H02K41/035; H02K41/0352; H02K41/0354; H02K41/0356; H04; H04R; H04R9/00; H04R9/02; H04R9/04; H04R9/046
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
159 words
Apparatus for compensating for the error component in a signal voltage induced in a signal winding surrounded by a substantially coaxial high permeability flux shield, where said error component is caused by variations in a powerful external magnetic field partially leaking through the flux shield in a non-uniform fashion along its length, and comprising: a. a compensating winding surrounding the flux shield and approximately coaxial with the signal winding, having a predetermined percentage of the number of turns of the signal winding and producing a compensation voltage responsive to variations in the external magnetic field; b. an amplifier receiving the compensation voltage and having a preselected voltage gain changing the R.M.S. value of the compensation voltage by a constant percentage value to continuously approximate the R.M.S. voltage of the error component in the signal voltage; and c. means for superimposing the amplifier output on the signal voltage and inverted with respect to the error component in the signal voltage.
Claim 2
Dependent Claim
159 words
Apparatus for compensating for the error component in a signal voltage induced in a signal winding surrounded by a substantially coaxial high permeability flux shield, where said error component is caused by variations in a powerful external magnetic field partially leaking through the flux shield in a non-uniform fashion along its length, and comprising: a. a compensating winding surrounding the flux shield and approximately coaxial with the signal winding, having a predetermined percentage of the number of turns of the signal winding and producing a compensation voltage responsive to variations in the external magnetic field; b. an amplifier receiving the compensation voltage and having a preselected voltage gain changing the R.M.S. value of the compensation voltage by a constant percentage value to continuously approximate the R.M.S. voltage of the error component in the signal voltage; and c. means for superimposing the amplifier output on the signal voltage and inverted with respect to the error component in the signal voltage.
Claim 3
Dependent Claim
153 words
Apparatus foR compensating for the error component in a signal voltage induced in a signal winding surrounded by a substantially coaxial high permeability flux shield, where said error component is caused by variations in a powerful external magnetic field partially leaking through the flux shield in a non-uniform fashion along its length, and comprising: a. a compensating winding surrounding the flux shield and approximately coaxial with the signal winding, having a predetermined percentage of the number of turns of the signal winding and producing a compensation voltage responsive to variations in the external magnetic field; b. an amplifier receiving the signal voltage and having a preselected voltage gain changing the R.M.S. value of the signal voltage by a constant percentage value to continuously approximate the R.M.S. voltage of the compensation voltage; and c. means for superimposing the compensation voltage on the amplified signal voltage and inverted with respect to the error component therein.
Claim 4
Dependent Claim
153 words
Apparatus foR compensating for the error component in a signal voltage induced in a signal winding surrounded by a substantially coaxial high permeability flux shield, where said error component is caused by variations in a powerful external magnetic field partially leaking through the flux shield in a non-uniform fashion along its length, and comprising: a. a compensating winding surrounding the flux shield and approximately coaxial with the signal winding, having a predetermined percentage of the number of turns of the signal winding and producing a compensation voltage responsive to variations in the external magnetic field; b. an amplifier receiving the signal voltage and having a preselected voltage gain changing the R.M.S. value of the signal voltage by a constant percentage value to continuously approximate the R.M.S. voltage of the compensation voltage; and c. means for superimposing the compensation voltage on the amplified signal voltage and inverted with respect to the error component therein.
Claim 5
Dependent Claim
173 words
A magnetic velocity transducer for a linear motor, of the type having a signal winding within an opening in the center pole piece of the motor with its axis approximately parallel to the path of the motor''s armature, and having a magnet within the signal winding mechanically shifted by the motor''s armature and inducing a velocity signal voltage in the signal winding and including apparatus for compensating the velocity signal voltage for errors caused therein by varying external flux comprising: a. a tubular flux shield of magnetically permeable material surrounding and substantially coaxial with the signal winding and carrying magnet flux through only a portion of its length at any time; b. a compensating winding surrounding and approximately coaxial with the flux shield, having a fraction of the number of turns of the signal winding, and supplying a compensation voltage induced therein by the varying external magnetic field; and c. means for superimposing the compensation voltage on the velocity signal voltage to at least partially cancel the errors in the velocity signal voltage.
Claim 6
Dependent Claim
173 words
A magnetic velocity transducer for a linear motor, of the type having a signal winding within an opening in the center pole piece of the motor with its axis approximately parallel to the path of the motor''s armature, and having a magnet within the signal winding mechanically shifted by the motor''s armature and inducing a velocity signal voltage in the signal winding and including apparatus for compensating the velocity signal voltage for errors caused therein by varying external flux comprising: a. a tubular flux shield of magnetically permeable material surrounding and substantially coaxial with the signal winding and carrying magnet flux through only a portion of its length at any time; b. a compensating winding surrounding and approximately coaxial with the flux shield, having a fraction of the number of turns of the signal winding, and supplying a compensation voltage induced therein by the varying external magnetic field; and c. means for superimposing the compensation voltage on the velocity signal voltage to at least partially cancel the errors in the velocity signal voltage.
Claim 7
Dependent Claim
35 words
The apparatus of claim 3, wherein the compensating winding has a fraction of the number of signal winding turns approximately equal to the fraction of the varying external magnetic field leaking through the flux shield.
Claim 8
Dependent Claim
24 words
The apparatus of claim 3, including means for changing one of the signal and compensation voltages by a fixed percentage to approximate the other.
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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) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |