Fig 4 - uploaded by Alexander I. Korolev
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Shceme of a wire arc 1 fixed on a thin dielectric cylinder 2. L is a length, R=2.75 mm is a radius. The curves of emf induced in the arcs with different length and fixed radius of 2.75 mm are presented in Fig. 5. The time is limited by a peak of the second pulse, when derivative of B(t) vanishes. Minimums of the curves correspond to the inflections of dependencies B(t) obtained using Hall sensor.
Source publication
Experimental validation of the Faraday's law of electromagnetic induction
(EMI) is performed when an electromotive force is generated in thin copper
turns, located inside a large magnetic coil. It has been established that the
electromotive force (emf) value should be dependent not only on changes of the
magnetic induction flux through a turn and o...
Context in source publication
Context 1
... arcs are made of copper wire with 0.1 mm in diameter and are fixed on a dielectric cylinder in the center of magnetic coil, normal to its axe (see Fig. 1). The ends of the arcs are bended so that the current outlets are parallel to the axe (see Fig. 4). From the physical point of view it is clear that induced emf is to be equal to zero in an arc of zero length. The family of curves of emf is obtained similarly for the arcs with different radii and of fixed length 5.5 mm. But the resulting relationships are ambiguous. That is because of the value of induced emf depends on the arc ...
Citations
... In this way, the inception of new formulae is recommendable and endeavor to enhance the computation and evaluation methods. A number of studies have been undertaken recently which take these objectives into account [16][17][18][19][20]. Thus, analytical techniques have demonstrated to be efficacious in computing the electromagnetic service losses. ...
South Africa is aiming to achieve a generation capacity of about 11.4GW through wind
energy systems, which will contribute nearly 15.1% of the country’s energy mix by 2030.
Wind energy is one of the principal renewable energy determinations by the South African
government, owing to affluent heavy winds in vast and remote coastal areas. In the design
of newfangled Wind Turbine Generator Step-Up (WTGSU) transformers, all feasible
measures are now being made to drive the optimal use of active components with the purpose
to raise frugality and to lighten the weight of these transformers. This undertaking is allied
with numerous challenges and one of them, which is particularly theoretical, is delineated
by the Eddy currents. Many times the transformer manufacturer and also the buyer will be
inclined to come to terms with some shortcomings triggered by Eddy currents. Still and all,
it is critical to understand where Eddy currents emanate and the amount of losses and
wherefore the temperature rise that may be produced in various active part components of
WTGSU transformers. This is the most ideal choice to inhibit potential failure of WTGSU
transformers arising from excessive heating especially under distorted harmonic load
conditions. In the current work, an extension of the author’s previous work, new analytical
formulae for the Eddy loss computation in WTGSU transformer winding conductors have
been explicitly derived, with appropriate contemplation of the fundamental and harmonic
load current. These formulae allow the distribution of the skin effect and computation of the
winding Eddy losses as a result of individual harmonics in the winding conductors. These
results can be utilized to enhance the design of WTGSU transformers and consequently
minimize the generation of hotspots in metallic structures.
... F= Load in kgf; d = Arithmetic mean of the two diagonals, d1 and d2 in mm; HV = Vickers hardness [11,12]. Analyzing Electromagnetic Signatures Table 4. Electromagnetic Assessment: All four blades were assessed for both their baseline magnetic properties as well as their electromagnetic properties when charged in electric circuit [13]. The level of magnetic strength was recorded as MicroTesla (µT) [14,15]; the bottom row shows the difference between baseline magnetism and electromagnetism. ...
... The expression for induced EMF in [10] was given without taking into ac- ( ) ...
... The magnetic field at a point is a result of physical superposition of the elementary magnetic fields from individual dipoles including the induced ones.Such representation of the superposition principle is, for example, here[9].Magnetic shielding is known to protect the conductor from the usual induced EMF while in the external alternating magnetic field. Why it does not protect against motional EMF?Work[10] introduces the concept of "magnetic force" acting on the charge located in the alternating magnetic field of some elementary source-dipole. If consider the effect of such forces to the shielded conductor in an alternating magnetic field taking into account the principle of superposition, one can find that they mutually compensate each other. ...
The motional EMF in segments of the copper wire with magnetic shielding is
found according to the voltage lack in two coils with partial shielding moving
relative to the magnetic field lines. The first coil moved across the Earth’s
magnetic field lines. The second one was located near the end face of the rotating
disk magnet with an axial magnetization. Permalloy foil wound around
a part of turns containing wire was used for shielding. The experiments result
reveals the penetrating ability of the magnetic field through the ferromagnetic
shield and shows the physical nature of the superposition principle. With this
in mind, a universal method for calculating EMF induced in a conductive
body has been provided as well as the concepts of magnetic field lines velocity
and acceleration have been introduced.
