In 5 and 6, ra was the exterior conductor's internal radius and ri was the phase conductors' radius, eo represented the air's dielectric constant, mo represented free space permeability and er was the relative dielectric constant.
En 5 y 6 ra es el radio interno del conductor exterior y ri el radio de los conductores de fase, εo es la constante dieléctrica del aire, mo es la permeabilidad del espacio libre y εr la constante dieléctrica relativa.