Regular maintenance of transformers is required for trouble free operation. One of the major maintenance includes rehabilitation of the transformer oil for removing carbon and iron materials, water and gas, and acids. Nisha engineering corporation offers filter machines from 250 lph to 10000 lph where the oil after passing through a strainer for removal of solid particles is subjected to vacuum under heated condition by indirect system of heating. The vacuum system from these company removes moisture or gas that present in the oil and improves the dielectric strength of the oil, making it suitable for reuse in the transformers. In certain cases, where there is need for maintaining very low value of dissolved gases and water, double or three stage of vacuum is used for maintaining very high levels of vacuum. Added advantage of these transformer oil filter machine includes filtration of oil at low temperatures. In some cases the company also provides acidity reaction column for removal of excess acid present in the oils. Some of the key factors of the product of these company better than others is economical costs, trouble free operation, easy maintenance, ease of handling, highly portable, easy cleaning and long life. Transformer oil filter machine, single & multi-stage, oil test sets, high voltage test sets, oil testing instrument, electrical, electrical equipment, heating equipment, transformer oil purification plant.