Inside View of Oil Filled Power Transformer
Inside of Oil Filled Transformer
Inside of Oil Filled Transformer
There seems to be some mystery around pad mount transformers. And not just the green boxes in residential back yards. Even the larger pad mount power transformers used by manufacturers seem to be a mystery to many folks. During a routine quarterly RCM (Reliability Centered Maintenance) Inspection of a manufacturing plant’s power transformers, MIDWEST detected a small amount of oil weepage on the concrete pad under one transformer. It was a 2000 Kva, 24,940Y/14,400 volt to 480Y/277 volt unit built in 1993 with 740 gallons of oil in it. When we explained to the owners that the main power transformer for their product assembly and finishing area was filled with oil and the oil was weeping out of the transformer, they almost thought we were joking. They had no idea the transformer was oil filled. A little walk, inspection, and explanation and we could tell it was now as clear as mud to them. They needed some pictures of the inside of the transformer. Oil weepage from a power transformer is nothing new, but this 2000 Kva power transformer went from no signs of weepage or leakage to a stained pad within 90 days. The cause was later determined to be a cracked bushing, which is very rare. In our report MIDWEST included pictures of the inside of a similar transformer. The images showed the oil inside the tank. Also showed the bushings extending inside the transformer under the oil and showed the liquid level gauge. Oddly enough, it was the oil level gauge that gave them the epiphany they needed to understand comfortably. These images are always very helpful as a “Seeing is believing” tool.