Power Transformers Blog – Expert Safety and Usage Info

A salvage company called MIDWEST and complained because they had an old transformer filled with silicone oil and they couldn’t get rid of it. It seemed to them that no one really wanted an old silicone oil transformer. At least no one would pay as much as they wanted for it.  They wanted to know why, because they knew oil filled transformers were used everywhere. Since MIDWEST Switchgear Division deals in used and new electrical power transformers, they came to us for some quick help. The simple answer is that silicone is not oil.  Transformer oil is mineral oil, much like you put into your car, but it is refined differently.  To use the term silicone oil doesn’t make sense.  You could say silicone dielectric fluid, but not oil.  Silicone filled transformers provide fire protection for indoor use. And since silicone is very expensive, it is not needed or used in outdoor fluid filled power transformers.  Regular oil filled transformers must be installed in a secure vault if installed indoors.  But they are used every where outdoors. Silicone is really never used outdoors. Therefore, for many installations, silicone has lost favor as a transformer fluid. It especially does not lend itself to informative routine dielectric testing or combustible gas-in-oil testing, which is commonly used to monitor the condition of old and new electrical power transformers used in industry.  It is a simple case of supply and demand. And there is not a great demand for old or refurbished or retrofilled, so called silicone oil filled transformers. We referred them to Dow Corning 561 Silicone Transformer Liquid if they wanted to know more about silicone. In addition, there are now substitutes for silicone dielectric fluid on the market.