Distribution Transformer Manufacturing Tour     High-grade grain-oriented silicon steel is automatically cut to length and tightly wound on modern equipment. Precisely formed echelon lapp joints promote lower losses. Each core is annealed after forming to eliminate stress in a computer controlled continuous annealling furnace. The atmosphere within the furnace is continuously purged with 100% Nitrogen to assure an Oxygen free environment which assures the lowest possible core losses.    Copper or aluminum magnet wire used in the high-voltage section of the coils is accurately placed between cuffed edges of thermally set diamond paper insulation.  Hard pressboard cooling ducts allow for an even flow of oil throughout the coil for cool efficient operation. Precision slit, and edge conditioned aluminum strip is used in the low voltage section to eliminate hot spots and for improved short circuit strength.  Winding tensions are carefully monitored and controlled throughout the winding processes to ensure a strong, tight coil assembly. Thermally upgraded electrical insulation grade Kraft paper, which has a diamond pattern heat set epoxy coating on both sides of the paper, is used throughout the coil to maximize short circuit strength.   After the core and coil is combined, it is secured by special frames and banding. Leads and accessories are added, and the finished assembly is baked to remove any moisture that may have been absorbed through the manufacturing process. The completed unit is retained in the tank by a three-point mounting system for superior strength.      Continue with tour   Return to transformers