Dry Type Transformer Life Expectancy
Frequently electricians and plant engineers ask how long dry type transformers last. The easy answer is, “Until they fail.” But that answer might result in a ‘click’ at the other end of the phone line. In this case we are talking about general purpose dry type air cooled transformers, 208, 240, and 480 volts. These transformers are located everywhere in manufacturing facilities. For most people they are just metal enclosures that are warm in the winter and make a funny humming sound. We were asked if they were good for 25 years or more.
The biggest enemy of air cooled dry type transformers are roof leaks and fork trucks. The transformers are good for many more than 25 years. But don’t let them get wet, dirty, hit, or buried under “stuff.” They do not like water or heat. If the ventilation is blocked, they may overheat and that will shorten their reliable life expectancy. So, if your general purpose, dry type, air cooled transformer is kept dry, clean, and well ventilated, it may last 30, 40, even 50 years. It should last until you retire, which has become the newest criteria for many electricians and plant engineers. Also, these transformers look innocent, but they are very dangerous, fatal, if they blow up or if something gets stuck inside the enclosure.
We are talking about transformers that might be 1000 kva with a primary voltage of 4160 volts or 13,200 volts and a secondary voltage of 480 or 208. They are in a metal enclosure with vents to allow air to circulate and cool the transformer. These transformers are indoor and usually found in locked electrical rooms. We see these transformers 60 years old and still humming away.