Conductors space factors

K. K , = geometrical factors, depending upon the more important parameters such as area of the grounding grid, its depth and conductor spacing and less important factors, such as diameter of the conductors and the thickness of the finishing surface by concrete or gravel. 

Figure 28.7 Space factor for rectangular conductors (Courtesy The Copper Development Association) Table 28.3 Derating factors on account of higher ambient temperature or restricted temperature rise...

Isc = r.m.s. value of fault current in Amperes = 45 000 A K = space factor for rectangular conductors, determined from the curves of Figure 28.7, corresponding to... 

The buried, or inner, via hole system has been introduced to optimize the space factors of the inner conductor layers as shown in Fig. 65.16. The inner layer circuits with via holes can be produced as the same process of the double-sided flexible circuits. Adhesiveless copper laminates made by the cast process or lamination process are recommended for use in minimizing the smear during the driUing and optimizing the heat resistance during the multiple high temperature processes. 

In general, the artificial (and generally incorrect) assumption was made that Acj) = 0 for a solid ionic conductor in contact with a graphite or noble metal electrode in the absence of an externally applied potential. The temperature and dopant level dependence of the experimental capacitance was then compared with the factor (2K Qe%j /kT) or its equivalent. Other aspects of this work are discussed elsewhere (3,18). To the author s knowledge, the validity of Eq. 2 for a solid ionic conductor with a low enough bulk defect concentration to expect predominant diffuse space charge capacitance has not yet been shown. 

It is often impractical to perform hi-pot tests on finished products, except at limited numbers of test points. Equipment limitations are one factor, it being expensive to construct test equipment and fixtures capable of routing such high-voltage signals to a large mrmber of test points. However, the product itself is often a poor target for such tests when evaluated in finished form. Modem products are often constmcted with relatively fine spaces between conductors. 

A number of factors affect CAF formation. These include substrate material, conductor configuration, processing, voltage and spacing, soldering flux, and humidity in the storage and use enviromnent. 

Two other critical factors used in determining CAF susceptibihty are voltage and spacing.The CAF growth is fueled by the electric field (V/d), and failure occurs more quickly with smaller spacing between conductors. 

The other important factor for obtaining conductive LB film is the dimensionality of the film-forming materials. Many of the molecular conductors have onedimensional band structures which are the source of exotic physical properties such as anistropy in conductivity or Peierls instability. However, a one-dimensional conduction band in a reciprocal lattice means also one-dimensional molecular interactions in real space. As a result, one-dimensional conductors are supposed to be very sensitive to defects and disorders which are inevitable in processing LB films at this stage. On the other hand, more-than-one-dimensional conductors seem to be more insensitive to defects and disorders. In addition, a higher dimensional Fermi surface will suppress transitions to insulators at lower temperature. 

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