ABSTRACT
At the end of this chapter you should be able to: • understand field plotting by curvilinear squares • show that the capacitance between concentric cylinders, C = 2πε0εr
ln(b/a) and calculate C given values of radii a and b
• calculate dielectric stress E = V r ln(b/a)• appreciate dimensions of the most economical cable
• show that the capacitance of an isolated twin line, C = πε0εr
ln(D/a) and calculateC given values ofa andD
• calculate energy stored in an electric field • show that the inductance of a concentric cylinder, L= µ0µr
2π
( 1 4
+ ln b a
) and calculate L given values
of a and b • show that the inductance of an isolated twin line, L= µ0µr
π
( 1 4
+ ln D a
) and calculate L given values
of a a and D • calculate energy stored in an electromagnetic field
40.1 Field plotting by curvilinear squares
Electric fields, magnetic fields and conduction fields (i.e. a region in which an electric current flows) are analogous, i.e. they all exhibit similar characteristics. Thus they may all be analysed by similar processes. In the following the electric field is analysed.
