US3671814A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electromagnet with a field-responsive control system
Assignee: Voith Getriebe KG
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Filing: 1971-04-22
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Granted: 1972-06-20
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Expires: 1991-04-22
Abstract
Abstract In an electromagnet, to generate a force which is independent from the armature position, an on-off control system for the excitation current is provided which operates as a function of the magnetic field intensity. The control system causes the excitation current to oscillate between two values and thus have a constant mean value according to a preset desired value. The timelag of the inductivity or its change between two close values is utilized for measuring the magnetic flux density and for a comparison with a desired value.
Inventors
- 👤 Heinrich Dick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:32
CPC Classifications
G; G05; G05F; G05F7/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
226 words
In an electromagnet of the type that includes (a) a magnet coil, (b) an iron cladding surrounding said magnet coil, (c) an armature movable within said coil and defining an air gap with a part of said cladding, (d) means for supplying an excitation current to said coil to generate a magnetic field passing through said air gap and exerting an inwardly directed attracting force to said armature and (e) means exerting an outwardly directed force on said armature; the intensity of said magnetic field being dependent upon the position of said armature from said cladding, the improvement comprising a circuit means for regulating said excitation current; and circuit means including A. a magnetic field intensity-responsive means disposed within said cladding and responding at least indirectly to the intensity of said magnetic field, B. setting means for obtaining signals corresponding to a desired value of magnetic force, C. comparator means for comparing the output signals of said magnetic field intensity-responsive means with those of said setting means and D. switching means for regulating the admission of said excitation current to said magnet coil in response to the output signals of said comparator means for providing in said air gap a magnetic field being of constant magnitude at least as to a mean value with respect to time and being independent from the position of said armature.
Claim 2
Dependent Claim
226 words
In an electromagnet of the type that includes (a) a magnet coil, (b) an iron cladding surrounding said magnet coil, (c) an armature movable within said coil and defining an air gap with a part of said cladding, (d) means for supplying an excitation current to said coil to generate a magnetic field passing through said air gap and exerting an inwardly directed attracting force to said armature and (e) means exerting an outwardly directed force on said armature; the intensity of said magnetic field being dependent upon the position of said armature from said cladding, the improvement comprising a circuit means for regulating said excitation current; and circuit means including A. a magnetic field intensity-responsive means disposed within said cladding and responding at least indirectly to the intensity of said magnetic field, B. setting means for obtaining signals corresponding to a desired value of magnetic force, C. comparator means for comparing the output signals of said magnetic field intensity-responsive means with those of said setting means and D. switching means for regulating the admission of said excitation current to said magnet coil in response to the output signals of said comparator means for providing in said air gap a magnetic field being of constant magnitude at least as to a mean value with respect to time and being independent from the position of said armature.
Claim 3
Dependent Claim
29 words
An improvement as defined in claim 1, wherein said means defined in (A) responds directly to the intensity of said magnetic field and is disposed in said air gap.
Claim 4
Dependent Claim
120 words
a variable resistor constituting said setting means, B. means for connecting two diagonal measuring points of said resistance bridge circuit to two inputs of said amplifier, C. a first transistor having a base to which the output signals of said amplifier are applied; said first transistor having a collector-emitter leg, D. a second, or power transistor having a base to which the signals of the collector-emitter leg of said first transistor are applied; said second transistor having a collector-emitter leg; said first and second transistors forming part of said switching means and E. a direct voltage source connected to diagonal feed points of said resistance bridge circuit and, through the collector-emitter leg of said second transistor, to said magnet coil.
Claim 5
Dependent Claim
120 words
a variable resistor constituting said setting means, B. means for connecting two diagonal measuring points of said resistance bridge circuit to two inputs of said amplifier, C. a first transistor having a base to which the output signals of said amplifier are applied; said first transistor having a collector-emitter leg, D. a second, or power transistor having a base to which the signals of the collector-emitter leg of said first transistor are applied; said second transistor having a collector-emitter leg; said first and second transistors forming part of said switching means and E. a direct voltage source connected to diagonal feed points of said resistance bridge circuit and, through the collector-emitter leg of said second transistor, to said magnet coil.
Claim 6
Dependent Claim
110 words
An improvement as defined in claim 2, including A. a field resistor constituting said magnetic field intensity-responsive means, B. means for applying the voltage drop across said field resistor to said comparator means for comparing said voltage drop with a desired potential difference prevailing at said setting means and C. an amplifier having input means for receiving the output signals of said comparator means, said amplifier having output means connected to said switching means for supplying the latter with an amplifier output current which is at least decreased when said voltage drop exceeds said desired potential difference and which is increased when said desired potential difference exceeds said voltage drop.
Claim 7
Dependent Claim
14 words
An improvement as defined in claim 3, including A. a resistance bridge circuit containing
Claim 8
Dependent Claim
22 words
An improvement as defined in claim 1, wheRein said means defined in (A) responds indirectly to the intensity of said magnetic field.
Claim 9
Dependent Claim
66 words
An improvement as defined in claim 5, including A. an auxiliary winding disposed inside said magnet coil and constituting said magnetic field intensity-responsive means; said auxiliary winding generates output signals induced therein by the excitation current flowing in said magnet coil and B. an integrating circuit connected to said auxiliary winding; said integrating circuit is connected to said comparator means for applying thereto its output signals.
Claim 10
Dependent Claim
156 words
An improvement as defined in claim 5, wherein said magnetic field intensity-responsive means is constituted by said magnet coil itself; and improvement further includes A. a differentiating circuit connected to said magnet coil to receive therefrom output signals that include a voltage component due to the self-induction in response to the excitation current; said differentiating circuit is adapted to suppress a direct voltage component of the coil output signal due to the ohmic resistance of said coil, B. a first integrating circuit connected to said differentiating circuit for delivering a voltage proportional to the change of the magnetic flux in said air gap and C. a second integrating circuit connected to said first integrating circuit for delivering a voltage proportional to the product of the momentary value of the excitation current and the momentary value of the inductance of said magnet coil; said last named voltage is applied to said comparator means including said setting means.
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) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |