Skin Effect: tendency of the current to crowd near the conductor surface.
Skin effect is proportional to frequency, conductor diameter and permiability. Skin effect increases effective resistance of conductor. In DC, no skin effect.
all day efficiency is ratio of energy output to the energy input taken over 24 hour period. design distribution transformer for max. efficiency occurring at the avarage output power. performance of distribution transformer represent by all day efficiency.
interpoles is widely use to improve commutation place between main poles fitted to yoke functions: to neutralize armature mmf in commutating zone to produce some flux in commutating zone
EXAMIANS