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Wyszukujesz frazę "demagnetization" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Magnetization dependent demagnetization characteristic of rare-earth permanent magnets
Autorzy:
Bavendiek, Gregor
Müller, Fabian
Sabirov, Jamshid
Hameyer, Kay
Powiązania:
https://bibliotekanauki.pl/articles/140527.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
demagnetization
magnetic hysteresis
magnetization processes
permanent magnets
Opis:
Accurate demagnetization modelling is mandatory for a reliable design of rare- earth permanent magnet applications, such as e.g. synchronous machines. The magnetization of rare-earth permanent magnets requires high magnetizing fields. For technical reasons, it is not always possible to completely and homogeneously achieve the required field strength during a pulse magnetization, due to stray fields or eddy currents. Not sufficiently magnetized magnets lose remanence as well as coercivity and the demagnetization characteristic becomes strongly nonlinear. It is state of the art to treat demagnetization curves as linear. This paper presents an approach to model the nonlinear demagnetization in dependence on the magnetization field strength. Measurements of magnetization dependent demagnetization characteristics of rare-earth permanent magnets are compared to an analytical model description. The physical meaning of the model parameters and the influence on them by incomplete magnetization are discussed for different rare-earth permanent magnet materials. Basically, the analytic function is able to map the occurring magnetization dependent demagnetization behavior. However, if the magnetization is incomplete, the model parameters have a strong nonlinear behavior and can only be partially attributed to physical effects. As a benefit the model can represent nonlinear demagnetization using a few parameters only. The original analytical model is from literature but has been adapted for the incomplete magnetization. The discussed effect is not sufficiently accurate modelled in literature. The sparse data in literature has been supplemented with additional pulsed-field magnetometer measurements.
Źródło:
Archives of Electrical Engineering; 2019, 68, 1; 33-45
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of rotor’s cage resistance on demagnetization process in the line start permanent magnet synchronous motor
Autorzy:
Zawilak, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/141077.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
demagnetization
falling out of step
permanent magnets
synchronous motor
Opis:
This paper deals with the finite element analysis of the demagnetization process of the line start permanent magnet synchronous motor. Special attention has been paid to demagnetization risk assessment after resynchronization during a short-term supply power outage. The current and torque waveforms have been determined assuming the difference depending initial rotor position angle. It has been demonstrated that the highest demagnetization risk occurs when resynchronization (motor reclosing) is performed when induced electromotive forces are in anti-phase to the supply voltage waveforms. The effect of cage winding resistance on the risk of demagnetization is examined and discussed.
Źródło:
Archives of Electrical Engineering; 2020, 69, 2; 249-258
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ekologiczne chłodziarki magnetyczne
Ecological magnetic refrigerators
Autorzy:
Sulima, R.
Powiązania:
https://bibliotekanauki.pl/articles/159969.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Elektrotechniki
Tematy:
chłodzenie magnetyczne
materiały magnetokaloryczne
magnesy trwałe
analiza polowa 2D
analiza polowa 3D
magnetic refrigeration
magnetocaloric materials
adiabatic demagnetization
permanent magnets
2D field analysis
3D field analysis
Opis:
Artykuł opisuje cykl przemiany energii w materiałach magnetokalorycznych, prototypy wybranych konstrukcji układów chłodzących, ich wady i zalety. Przedstawiono również tło polityczne i warunki środowiskowe wymagane przez UE w stosunku do urządzeń chłodniczych i klimatyzacyjnych.
The magnetocaloric effect (MCE) is a thermodynamic process in which the temperature changes of a paramagnetic material are the effect of an external magnetic field changing in cycles. The refrigeration occurs in two stages: the first one is the isothermal magnetizing of the material, during which the intensity of the magnetic field rises from H0 to H3 (Fig. 1 process 1-2); during the magnetizing the dipoles of the paramagnetic material become arranged parallely to the intensity of the external magnetic field and the entropy of the material decreases from S1 to S2. As a result of magnetizing, heat is transferred to the surroundings in a quantity proportional to the work executed by the magnetic field. The second stage is the adiabatic demagnetization of the paramagnetic material to the value of the field intensity of H0, during which there occures a decrease in temperature of the material from Tp to T12 (Fig. 2 process 2-3).
Źródło:
Prace Instytutu Elektrotechniki; 2013, 261; 117-128
0032-6216
Pojawia się w:
Prace Instytutu Elektrotechniki
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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