Overhauling of Transformers:
As compared with most electric apparatus, transformers require relatively little attention. The extent of the inspection and maintenance required will be governed by the size, importance of service continuity, the location on the system, and operating conditions, such as ambient temperature, dirty atmosphere, heavy fogs and water supply (in the case of water-cooled units). Distribution transformers and small power transformers ordinarily require and receive less attention than large transformers, which represent a much greater investment. However, small transformers sometimes supply power to industrial loads where continuity of service is of the utmost importance. In these cases, a greater degree of attention is justified. A rigid system of inspection and preventive maintenance will ensure long life, trouble-free service and low maintenance cost. Maintenance shall consist of regular inspection, testing and reconditioning, where necessary. The amount of attention and maintenance vary with the service conditions and load cycle of the transformers. Records shall be kept of each transformer giving details of all inspections and testing made and of unusual occurrences. The principal object of maintenance is to maintain the insulation in good condition. Moisture, dirt and excessive heat in contact with oxygen, are the main causes of insulation deterioration and avoidance of these will, in general, keep the insulation in good condition. The limiting factor is the ageing of the insulation and decline in the quality of the insulation during the ageing process due to chemical and physical effects. The decay of the insulation follows the chemical reaction rate.
With regular maintenance, the services from any transformer can be enjoyed years together. Only a little bit of attention and minimum investment on spares and skilled services gives us a beautiful result in its life time.
