While estimating the overhead lines, the first and last pole is always earth connected and after every 3rd electrical pole, the fourth pole is earthed. Therefore, the approximate number of required ground set = 4
Lap Winding:-In a lap winding the number of parallel paths (a) is always equal to the number of poles (p) and also to the number of brushes. In the given question number of poles is 4 hence the number of brushes will be 4. Wave Winding:- In wave windings, the number of parallel paths (a) is always two and there may be two or more brush positions.
In nuclear power plant the graphite is used as a moderator. The job of the moderator is to absorb some of the kinetic energy of the neutrons to slow them down. This is because slow neutrons are more easily absorbed by uranium-235. A neutron slowed In this way can start the fission process.
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