EP1796113A1 - Réglage automatique de la fréquence de résonance de démagnétisation des piéces différentes pour installations de démagnetisation - Google Patents

Réglage automatique de la fréquence de résonance de démagnétisation des piéces différentes pour installations de démagnetisation Download PDF

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Publication number
EP1796113A1
EP1796113A1 EP05027030A EP05027030A EP1796113A1 EP 1796113 A1 EP1796113 A1 EP 1796113A1 EP 05027030 A EP05027030 A EP 05027030A EP 05027030 A EP05027030 A EP 05027030A EP 1796113 A1 EP1796113 A1 EP 1796113A1
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EP
European Patent Office
Prior art keywords
frequency
current
resonant circuit
coil
resonant
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EP05027030A
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German (de)
English (en)
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Urs Meyer
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Individual
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Individual
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Priority to EP05027030A priority Critical patent/EP1796113A1/fr
Priority to US11/636,309 priority patent/US20070133142A1/en
Publication of EP1796113A1 publication Critical patent/EP1796113A1/fr
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F13/00—Apparatus or processes for magnetising or demagnetising
    • H01F13/006—Methods and devices for demagnetising of magnetic bodies, e.g. workpieces, sheet material

Definitions

  • the invention relates to a method for automatically adjusting the resonant frequency during demagnetization of different objects in demagnetizers according to the preamble of the independent claim.
  • a known method for demagnetizing objects uses an open magnetic circuit, for example with a bar magnet or a magnetic yoke, and with a coil, which is traversed by a constant alternating current.
  • the magnetic circuit is applied to the object to be demagnetized and the alternating current is turned on. Then the magnetic circuit is slowly pulled away from the object by hand.
  • size and weight of the magnetic circuit are limited.
  • the demagnetization process is strongly influenced by ambient conditions. The demagnetization is incomplete and not perfectly reproducible.
  • the ferromagnetic objects as a whole are completely demagnetized by remaining locally fixed in the magnetic field of a coil during a certain time and thereby being exposed to an alternating field of decaying amplitude.
  • the alternating field of the coil with respect to frequency and amplitude is generated variably by an electronic supply source.
  • the alternating field is brought from a maximum value continuously decreasing to zero.
  • the objects are now demagnetized so far that no residual magnetism is measurable.
  • the demagnetization process takes place cyclically. This method has proven itself in applications with objects to be demagnetized always the same type and also provides the most complete demagnetization.
  • the capacitor is connected in series with the coil, and for powering a pulse width modulated inverter of conventional design is used. This compensates for the inductive reactive power of the coil and relieves the supply source.
  • this requires an operation in the state of resonance of the resonant circuit, that is, the feeding frequency must match the resonant frequency of the resonant circuit. This results in an additional problem in that, when the coil is subjected to different loads by objects to be demagnetized, its inductance, and therefore also the resonant frequency of the resonant circuit, changes.
  • the resonance frequency is not exactly known in advance, the operation at the resonance point is not ensured, and the course of the demagnetizing current depends on the application of the coil to the objects to be demagnetized. Thus, the quality of the demagnetization process from batch to batch is different and not exactly manageable.
  • the object of the invention is therefore to find a method which does not have the above disadvantages.
  • the object is achieved by automatically and accurately determining the resonance frequency of the resonant circuit loaded with arbitrary objects with the demagnetizing coil itself in a very short time, so that a demagnetization process, for example according to EP 1465217 , can begin immediately with the exact resonance frequency. This also ensures that the actual current value precisely follows the specified current setpoint throughout the demagnetization process.
  • the advantage of the invention is that no unnecessary time is required to travel through the resonance frequency for the beginning of the demagnetization process.
  • the throughput of the demagnetization system is thus considerably increased.
  • no lead time is wasted, and the process begins immediately after loading the resonant circuit with the correct resonant frequency.
  • a clocked demagnetization of different batches in terms of mass, material and configuration can be performed with correspondingly different resonant frequencies without undue delay and energy consumption.
  • FIG. 1 shows the course of the current I during the time t, according to the method according to FIG DE 30 05 927 A1 ,
  • the current profile I is compared to the optimal current profile I-soll.
  • the demagnetization takes place in an uncontrolled manner with the passage of the resonance point at any point 12.
  • a controlled demagnetization takes place only in the range of a second period of time with regulated current.
  • the drop of the curve D is regulated only in section 12 and so also reproducible.
  • the frequency is reduced from an increased output frequency fa to a demagnetizing frequency fm. In doing so, the resonant frequency fr is reached at any point in between.
  • An alternative route according to FIG. 2a operates with an auxiliary coil of small cross-section, which determines the admittance of the auxiliary coil 21, and thus the inductance of the demagnetizing coil 20 and, after further conversion, the corresponding resonant frequency.
  • This does not generate additional power dissipation in the coil and can be solved with reasonable effort on electronics.
  • the auxiliary coil 21 must be isolated from the degaussing coil 20 for the highest occurring voltage in the demagnetizing cycle, and the detected resonance frequency is inaccurate in that it is determined at very low currents where the. Permeability of the material to be demagnetized at most is still less effective.
  • a test is carried out with the loaded coil before each demagnetization.
  • the resonant frequency is determined with a small test current Up. Subsequently is started with the maximum demagnetizing current to resonant frequency of the demagnetization with controlled demagnetization current U.
  • the preferred way according to the invention operates with a control loop which automatically keeps the output frequency of the inverter at the resonance point of the resonant circuit. It is based on the measurement of the phase position of voltage and current at the output of the inverter. If the injected frequency is higher than the resonant frequency, the resonant circuit behaves inductively, i. the current follows the voltage behind, and the difference in phase of current and voltage is negative. If the injected frequency is lower than the resonance frequency, the resonant circuit behaves capacitively and the current leads the voltage. The corresponding phase angle is positive.
  • phase angle takes place in the inverter itself, by the zero crossings and their direction of current and voltage are determined.
  • the two signals are in the inverter anyway for the current loop, i. to control the power level, needed. They are therefore available without extra effort.
  • a frequency tracking due to the phase angle requires only an additional subprogram, which is solved purely by software.
  • the control circuit 30 of the supply of the demagnetizing coil L is shown.
  • the resonant circuit consists of a capacitor C, a resistor R and the applied coil L.
  • FIG. 3b shows the dependence on admittance and phase angle when the coil is loaded.
  • the frequency f is located on the x-axis and the admittance Ad and the phase angle Pw are located on the y-axis.
  • the resonant frequency fr of the charged coil the phase angle between voltage and current at the feed point of the resonant circuit passes through the zero point. This is the resonance point. Only when the coil is energized with this resonance frequency is a full and reproducible demagnetization possible.
  • FIG. 3c shows the phase position of voltage U and current I at the output of the inverter.
  • the method can also be used with a coil (tunnel demagnetizer) which is acted upon by continuous current, in that the frequency during the passage of the material through the coil is continuously kept at the resonance point and tracked.
  • the coil of the tunnel demagnetizer is supplied with continuous current, wherein the frequency is automatically held and tracked during the passage of the material through the coil in the resonance point.
EP05027030A 2005-12-10 2005-12-10 Réglage automatique de la fréquence de résonance de démagnétisation des piéces différentes pour installations de démagnetisation Withdrawn EP1796113A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP05027030A EP1796113A1 (fr) 2005-12-10 2005-12-10 Réglage automatique de la fréquence de résonance de démagnétisation des piéces différentes pour installations de démagnetisation
US11/636,309 US20070133142A1 (en) 2005-12-10 2006-12-07 Automatic setting of the resonant frequency on demagnetization of different parts in demagnetization installations

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP05027030A EP1796113A1 (fr) 2005-12-10 2005-12-10 Réglage automatique de la fréquence de résonance de démagnétisation des piéces différentes pour installations de démagnetisation

Publications (1)

Publication Number Publication Date
EP1796113A1 true EP1796113A1 (fr) 2007-06-13

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EP05027030A Withdrawn EP1796113A1 (fr) 2005-12-10 2005-12-10 Réglage automatique de la fréquence de résonance de démagnétisation des piéces différentes pour installations de démagnetisation

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US (1) US20070133142A1 (fr)
EP (1) EP1796113A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008007896A1 (de) 2007-02-21 2008-08-28 Albert Maurer Entmagnetisierverfahren
CN103545080A (zh) * 2013-02-01 2014-01-29 盐城工学院 一种交流变频电磁感应磁化装置
DE102018127614A1 (de) * 2018-11-06 2020-05-07 Albert Maurer Vorrichtung zum Entmagnetisieren von ferromagnetischen Materialien
DE102020121738A1 (de) 2020-08-19 2022-02-24 Marek Rohner Verfahren und Vorrichtung zum Entmagnetisieren von Objekten
CN117423525A (zh) * 2023-12-18 2024-01-19 保定天威新域科技发展有限公司 一种能量对冲方式振荡消磁能量注入控制系统

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080030916A1 (en) * 2006-07-26 2008-02-07 Elvir Kahrimanovic Thyristor controlled alternating current demagnetizer
CN103456457B (zh) * 2013-08-20 2015-10-28 江苏科技大学 高强钢窄间隙焊接坡口退磁方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3005927A1 (de) * 1980-02-16 1981-09-03 Erich Dr.-Ing. 5300 Bonn Steingroever Entmagnetisier-verfahren
DE3500011A1 (de) * 1985-01-02 1985-06-13 Axel R. Dr.-Ing. 5900 Siegen Hidde Verfahren und anordnung zur geregelten entmagnetisierung stabfoermiger, ferromagnetischer und vergueteter halb- oder fertigfabrikate im laufenden produktionsprozess

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3481184A (en) * 1967-07-14 1969-12-02 Ibm Core testing methods and apparatus
US4672345A (en) * 1985-09-24 1987-06-09 Electro-Matic Products Co. Degausser/demagnetizer
US4965532A (en) * 1988-06-17 1990-10-23 Olympus Optical Co., Ltd. Circuit for driving ultrasonic transducer
EP1465217A1 (fr) * 2003-04-02 2004-10-06 Albert Maurer Procédé et appareil pour démagnétiser des objets

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3005927A1 (de) * 1980-02-16 1981-09-03 Erich Dr.-Ing. 5300 Bonn Steingroever Entmagnetisier-verfahren
DE3500011A1 (de) * 1985-01-02 1985-06-13 Axel R. Dr.-Ing. 5900 Siegen Hidde Verfahren und anordnung zur geregelten entmagnetisierung stabfoermiger, ferromagnetischer und vergueteter halb- oder fertigfabrikate im laufenden produktionsprozess

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008007896A1 (de) 2007-02-21 2008-08-28 Albert Maurer Entmagnetisierverfahren
US7457095B2 (en) 2007-02-21 2008-11-25 Albert Maurer Demagnetizing method
DE102008007896B4 (de) 2007-02-21 2019-06-27 Albert Maurer Entmagnetisierverfahren
CN103545080A (zh) * 2013-02-01 2014-01-29 盐城工学院 一种交流变频电磁感应磁化装置
DE102018127614A1 (de) * 2018-11-06 2020-05-07 Albert Maurer Vorrichtung zum Entmagnetisieren von ferromagnetischen Materialien
DE102020121738A1 (de) 2020-08-19 2022-02-24 Marek Rohner Verfahren und Vorrichtung zum Entmagnetisieren von Objekten
CN117423525A (zh) * 2023-12-18 2024-01-19 保定天威新域科技发展有限公司 一种能量对冲方式振荡消磁能量注入控制系统
CN117423525B (zh) * 2023-12-18 2024-03-01 保定天威新域科技发展有限公司 一种能量对冲方式振荡消磁能量注入控制系统

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