Power Transformers Blog – Expert Safety and Usage Info

MIDWEST frequently gets calls from someone wanting to sell used electrical equipment. We are very cautious of the biography of the equipment when the seller is someone other than the original owner. When there are any concerns, the equipment is shipped to MIDWEST, then thoroughly inspected and tested, before we consider purchasing. There are many concerns relating to the condition of used electrical equipment, so we may request pictures, prior use, nameplate data, and other details. Usually a visual inspection is the first line of rejection. With a little biographical information we can frequently determine that the equipment is scrap. As an example, we received a request to sell us three used 1000 kva 13,200 volt to 480/277 volt air cooled, dry type power transformers. The seller was not the company that had used the transformer and the condition was described as “In great condition.” He said he had the transformers for over two years and just wanted to sell them. We asked for pictures before shipping. We got the pictures and the transformers look great. No indications of structural damage. Paint condition indicated the transformers were probably used in a clean environment, a commercial building for example, rather than a manufacturing plant. But, the pictures showed the transformers stored outdoors. Outdoors in the rain and whatever might blow into the windings. Immediate rejection. The windings would be wet and contaminated. Because of the location, the moisture in the windings would have frozen in the winter. The steel structure would be rusted. And if they stored these transformers outside, they had little knowledge of the proper handling of 15 kv dry type general purpose transformers. The pictures said it all. Junk.