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Direct Current (dc) Electronics
Published in Dale R. Patrick, Stephen W. Fardo, Electricity and Electronics Fundamentals, 2020
Dale R. Patrick, Stephen W. Fardo
A relationship similar to Ohm’s law for electrical circuits exists in magnetic circuits. Magnetic circuits have magnetomotive force (MMF), magnetic flux (Φ), and reluctance (R). MMF is the force that causes a magnetic flux to be developed. Magnetic flux consists of the lines of force around a magnetic material. Reluctance is the opposition to the development of a magnetic flux. These terms may be compared to voltage, current, and resistance in electrical circuits, as shown in Figure 1-86. When MMF increases, magnetic flux increases. Remember that in an electrical circuit, when voltage increases, current increases. When resistance in an electrical circuit increases, current decreases. When reluctance of a magnetic circuit increases, magnetic flux decreases. The relationship of magnetic and electrical terms in Figure 1-86 should be studied.
Magnetic separation
Published in D.V. Subba Rao, Mineral Beneficiation, 2011
The magnetic pressure which sets up or tends to set up magnetic flux in a magnetic circuit is called magneto-motive force (m.m.f). m.m.f is produced by passing electric current through a wire of number of turns. It is measured in ampere turns, generally written as AT, and is the product of number of turns (N) and the current (I) flowing through these turns. m.m.f. = N × I. The opposition to magnetic flux in a magnetic circuit is known as reluctance. The reluctance is directly proportional to the length of magnetic path (l), inversely proportional to the area of cross-section of the material through which flux is passing (A) and depends on the nature of the material. Reluctance=lAμoμr
Fundamental Electrical Engineering Concepts and Principles
Published in S. Bobby Rauf, Electrical Engineering Fundamentals, 2020
Magnetic reluctance can also be perceived as magnetic resistance; a resistance that opposes the flow of magnetic flux. Like resistance, reluctance is a scalar entity, but unlike electric resistance, it stores magnetic energy instead of dissipating it. Reluctance is measured in ampere-turns per weber or turns per henry. Ferromagnetic substances such as iron have low reluctance while dielectric substances like air and vacuum offer high reluctance to magnetic flux. That is the reason why transformers, contactors, relays, and other similar electromagnetic devices utilize iron – or iron alloy – cores.
An optimal selection of slot/pole combination and its influence on energy efficient PMSM for submersible water pumping applications
Published in International Journal of Ambient Energy, 2023
Anand Mouttouvelou, Vinod Balakrishna, Sundaram Maruthachalam, Suresh Muthusamy, Hitesh Panchal, Meenakumari Ramachandran, Vennila Ammasi
The magnetic system of the SBLPMM consists of the stator, air gap and the rotor. The performance of the magnetic circuit of the SBLPMM is determined by its air gap flux density which is attributed by the size, location and hence the direction of magnetisation of the permanent magnets. The magnetic flux flow path of the machine can be studied by its equivalent magnetic circuit based on the non-linear reluctance model which can be easily computed using the FEM analysis. In the SBLPMM, the permanent magnets are considered as the flux source. The flux from the permanent magnets are classified as the main flux, which aids in electromagnetic energy conversion and the leakage flux, which degrades the performance of the SBLPMM. The magnetic circuit should comprise both the useful and leakage flux in estimating the flux density at the optimally loaded conditions. Also, the magnetic circuits vary according to the type of permanent magnet rotor configurations (Braiwish 2016). The SBLPMM considered in this research work is of the PMSM type which comes under the category of surface permanent magnet (SPM) type PMSM. The magnetic equivalent circuit of the SBLPMM by consideration of one pole side is depicted in Figure 7 (Braiwish 2016).
Multi-Phase Permanent Magnet Generator with Halbach Array for Direct Driven Wind Turbine: A Hybrid Technique
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Janarthanan Balakrishnan, Chinnathambi Govindaraju
The graph represents that the magnetization curves utilized to stator core are shown in Figure 9(b). The graph represents the Stator’s inductance for all case studies: (a) stator inductor based on M14 and M19 (b) stator inductor based on M27 and M43 portrays on Figure 10. In Figure 11, the graph signifies the reluctance versus magnetic flux density. The graph represents the efficiency for the case studies: (a) efficiency based on M14 and M19 (b) is depicted in Figure 12. The graph represents the output power: (a) output power based on M14 and M19 and (b) output power based on M27 and M43 is shown in Figure 13. The graph represents the output power versus angular velocity is shown in Figure 14. The graph represents the VTHD for all case studies (a) VTHD based on M14 and M17 and (b) VTHD based on M27 and M43 is shown in Figure 15. The graph represents the Saturation of M14 as shown in Figure 16. The graph represents the Cogging torque to every case studies: (a) Cogging torque based on M14 and M19 and (b) Cogging torque based on M27 and M43 as shown in Figure 17.
Design and performance study of a segmented intelligent isolation bearing
Published in International Journal of Smart and Nano Materials, 2021
Guo-Jun Yu, Xi-Xi Wen, Cheng-Bin Du, Ling-Yun Wang, Shao-Jie Zhu
As an important part of SIIB, the design of the magnetic circuit structure will directly affect the performance of isolation bearing. The design magnetic circuit of the SIIB is shown in.According to the relationship between magnetic potential and magnetic flux, the equivalent magnetic circuit can be obtained as shown in . In , F1 is the magnetic potential generated by the excitation coils in the MRE layer; F2 is the magnetic potential generated by the excitation coils in the arc shell layer; Φ1 and R1 are the magnetic flux and magnetoresistance of MRE; Φ2 and R2 are the magnetic flux and magnetoresistance of STMP; ΦA and RA, ΦB and RB, ΦC and RC, are magnetic flux and magnetoresistance at position A, B, and C, respectively. According to Ohm’s law of magnetic circuit, the reluctance everywhere can be expressed by the following equation. The parameter is shown in.