Atoms or ions with unpaired electrons are attracted to a magnetic field; the more unpaired electrons, the greater is the attraction. Such substances are called paramagnetic. Molecular oxygen is a paramagnetic gas by virtue of its two unpaired electrons.
No of disc required for 11 kV transmission line = 1 disc Since the transmission line is 3-phase, therefore, the number of discs required for a single-pole will be 3. Total no. of poles = 80 No of disc = 3 × 80 = 240