1. CORE AND COIL:

1.1 The core shall be built of high quality, low loss, non-ageing high permeability grain-oriented, cold rolled silicon steel lamination with very low magnetization losses and annealed to relieve stresses and develop excellent magnetic properties.1.2 The core-clamping frame shall be provided with lifting eyes for the purpose of taking and inspecting the core with windings mounted thereon and shall have ample strength to take the full weight of the core and winding assembly. The core assembly shall be electrically connected to the transformer tank for effective core earthing.1.3 All insulating materials shall be of proven design. Coils shall be so insulated that voltage stresses are minimum.1.4 The windings shall be from electrolytic copper conductor of high conductivity with suitable Class "A" insulation. The windings shall be duly sectionalised. Similar coils shall be connected by accessible joints braced or welded and finished smooth.1.5 Coil assembly shall be securely positioned with spacers, pressed board cylinders, barriers and shall be so arranged as to allow free circulation of the oil.1.6 All leads from the windings shall be suitably supported to prevent damage from vibration or short-circuit stresses.