China
Africa
Explore chapters and articles related to this topic
Electromagnetic Principles of Switched Reluctance Machines
Published in Berker Bilgin, James Weisheng Jiang, Ali Emadi, Switched Reluctance Motor Drives, 2019
The unit of a magnetic field is equal to [N/Am] and it is called a tesla. Biot-Savart law states that the magnetic field vector created by a steady current depends on the magnitude, direction, length, and proximity of the electric current. Steady current here refers to a continuous flow of electrons through a conductor without any change in motion or, in other words, without picking up new electrons into the motion.
Magnetic Fields
Published in David Jiles, Introduction to Magnetism and Magnetic Materials, 2015
The Biot-Savart law, which enables us to calculate the magnetic field H generated by an electrical current, is one of the fundamental laws of electromagnetism. It is a statement of experimental observation rather than a theoretical prediction. In its usual form, the law gives the field contribution generated by a current flowing in an elementary length of conductor () δH=14πr2iδl×u
Miscellaneous Algorithms
Published in Nazmul Siddique, Hojjat Adeli, Nature-Inspired Computing, 2017
The standard CSS algorithm is based on the Coulomb and Gauss laws, which describe the electric field at a point inside and outside a charged insulating solid sphere shown in Figure 10.5. The forces expressed by Equation 10.90 do not take into account of the magnetic force. It was H.C. Oersted who discovered by accident a new phenomenon (i.e., magnetic field) caused by steady moving charges (i.e., electric current) in wires in 1820 (Oersted, 1820). Shortly after Oersted's finding, Andre-Marie Ampere published his findings on current flowing in wires exerts forces on one another (Ampere, 1820). In the same year of 1820, J.-B. Biot and F. Savart repeated Oersted's experiments and formulated a compact law of static magnetic fields generated by current in a circuit, which later became known as Biot–Savart law (Biot and Savart, 1820). The Biot–Savart law is the most basic law of magnetostatics. It describes how the magnetic field B at a given point P is produced by the moving charges (i.e., current) in the neighborhood of that point as shown in Figure 10.6. Biot–Savart law defines the magnitude of magnetic field at any point of the space in terms of the electric current that produces the field. dB=μ04πIds×r^r2 where μ0 is the permeability constant of free space, I is the current, Ids is the differential current element, r^ is the unit vector pointing from the location of the current element to the field point, and r is the distance between point P and ds. The cross product (×) indicates that dB is perpendicular to both ds and r^.
Analysis, Design, and Development of a Compact LVDT for In-Reactor Experiments
Published in IETE Journal of Education, 2019
Suman Saurav, M. Muthuganesh, P. K. Chaurasia, S. Murugan
The distance vector between the line P and T is Magnitude of the distance vector is and small current element vector Also, Magnetic field () due to current element at point T (according to the Biot –Savart law) is The cross product of the current element and distance vector is considered only in x-direction because change in magnetic field of x-direction will measure the displacement of the core.
Algorithms for the Magnetic Assessment of Proton Exchange Membrane (PEM) Fuel Cells
Published in Research in Nondestructive Evaluation, 2018
A small defect in the PEM may be treated as region of zero current density. The total current in the PEM can be viewed as a superposition of a defect-free current and a current dipole flowing in the opposite direction within the volume of the flaw. In Fig. 1, the current density of a membrane containing a pinhole is obtained from a defect-free membrane carrying a current J and a small volume carrying a current density –J over a volume V. The change in field due to the defect can then be calculated as the field that would be produced by an equivalent current dipole. The magnetic field at a location produced by the proton current in the membrane located at is given by the Biot-Savart Law:
About a New Fusion Reactor Scheme
Published in Fusion Science and Technology, 2018
This is reminiscent of the racetrack plasma configuration that was pioneered in the early stages of thermonuclear fusion research by the Matterhorn Project with the Model C Stellarator.7 However, while the straight sections of the latter were kept to a minimum and used for plasma divertors and the location of heating systems, in the present proposal the size of the straight sections is set, as explained above, to maximize the ratio of their plasma volume to that of the curved sections. An example, illustrated in Fig. 1, shows the footprint of a set of circular coils with a radius of 6.0 m (meter will be the unit of length throughout the paper) and centers describing a racetrack with curved sections having a radius Rc = 15 m and straight sections with length . Shown are also two magnetic field lines from a ray tracing code based on the Runge-Kutta method8 in combination with the Biot-Savart law.9 These lines define the footprint of a circular plasma with a radius of 2.5 m. If then we take L = 400 m, i.e., 8.5 times the length of a circular section, we get a total plasma volume of 17.5 × 103 m3, 20.9 times larger than the volume of ITER (840 m3) (Ref. 2). Hence, it should be capable of producing 10.4 GW of fusion power when operating in DT at the same density, temperature, and confining magnetic field of ITER, i.e., at the same β.