Forces electrodynamic

To obtain a strong busbar mounting system, suitable to withstand the electrodynamic forces arising out of a system fault, modern practice is to make use of thermosetting plastics, such as DMC (Dough Moulding Compounds)... 

The magnitude of electrodynamic forces on the primary windings, which may be developed by the discharge currents. 

Protection against electrodynamic forces. These are caused by transient currents, such as on faults, and mainly affect the overhangs or the parts of the windings that fall outside the stator slots. These parts are specially braced and strengthened at the time of manufacture. 

The electrodynamic forces may exist for only three or four cycles (Section 13.4.1(7)), but the mechanical system must be designed for these forces. On the other hand, the main current-carrying system is designed for the symmetrical fault current, 1 (Table 13.7) for one or three seconds according to the system design. For more details refer to Section 13.5. 

Below we discuss the thermal effects and the electrodynamic forces which may develop during a fault to decide on the correct size of the conductor and its supporting system. 

The electrodynamic forces between the enclosure and the conductors will be small because the enclosure, which is non-continuous, will carry much less current than the main conductors. They therefore need not be considered separately, as the metallic structure will have sufficient strength to bear them. 

F = maximum electrodynamic forces acting on each support, in the event of a fault, as calculated above = 514 kgf / = centre distance between two busbar supports = 40 cm M = sectional modulus of each busbar at section x - x... 

When using the above metals for the purpose of current carrying, their mechanical suitability must be checked with the data provided above to withstand, without permanent deformation, the electrodynamic forces that may develop during a short-circuit condition (Section 28.4.2). 

The electrodynamic forces proposed for stabilizing jellium provide the principal type of bonding in molecular crystals such as solid methane, rare gas crystals, solid anthracene, and the like. These forces also form the inter-chain bonding of long-chain molecules in polymeric materials (the intra-molecular bonding within the chains is usually covalent). 

The causative part of GAm/Bm(Z, T) is merely the sum of products (eA — em)(eB — em) formally (but only formally ) like the product of differences (NAcA — Nmcm)(NBcB — Nmcm) in pairwise summation. It is as though the electromagnetic waves that constitute the electrodynamic force were waves in a medium m that suffered only small perturbations because of the small difference between sA, sB and em. It is not because the atoms in the different media see each other individually, as imagined in pairwise summation the i s are not proportional to the respective number density N,. 

As emphasized elsewhere in this text, the physical act constituting an electrodynamic force is the correlated time-varying fluctuation of all component electric charges and electromagnetic fields in each material composing a system. Charge fluctuations at each point are either spontaneous or are in response to electric fields set up by fluctuations elsewhere. The dielectric permittivity is an experimental quantity that codifies not only the response of a material to an applied electric field but also the magnitude of spontaneous fluctuations. 

As described in earlier sections, any two material bodies will interact across an intermediate substance or space. This interaction is rooted in the electromagnetic fluctuations— spontaneous, transient electric and magnetic fields—that occur in material bodies as well as in vacuum cavities. The frequency spectrum of these fluctuations is uniquely related to the electromagnetic absorption spectrum, the natural resonance frequencies of the particular material. In principle, electrodynamic forces can be calculated from absorption spectra. 

Scheme 16.1 In a metal, the plasma is created by the combination of an ion gas and an electron gas. The plasma is then disturbed by the absorption of a photon. The resulting electrodynamic force is causing an oscillation, which is known as plasmon.

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