Dry Type Transformers "transform" voltage either up to a higher voltage (step up) or down (step down) to a lower voltage. Normally, that transformation takes place when power line transmission voltages (such as 500 kV) are "stepped down" to a much lower level, suitable for use by iindustrial power systems (30 kV) aor residential (120-240V). Dry type transformers accomplish this so efficiently that they are very often suited for indoor applications where oil-filled transformers are thought of as unsuitable.
“Dry type” simply means it is cooled by normal air ventilation. A dry type transformer does not require a liquid such as oil or silicone or any other liquid to cool the electrical core and coils.
Dry type transformers require minimum electrical maintenance and provide many years of reliable trouble-free service. Unlike liquid filled transformers, which are cooled with oil or fire resistant liquid dielectric, a dry type transfomer utilizes only environmentally safe, CSA and UL recognized high temperature insulation systems. Dry type transformers provide a safe and reliable power source which does not require fire proof vaults, catch basins or the venting of toxic gasses. These important safety factors allow the installation of dry type transformers inside buildings close to the load, which improves overall system regulation and reduces costly secondary line losses.
Dry type transformers are a rather mature product and technology but, of all the components in a power system, a transformer replacement can be a physically challenging event, extended delivery of a replacement or repair unit and expensive transportation costs.
These are transformers whose core and coils are not immersed in an insulating oil.
Fire-resistant dry type or "cast resin" transformers are well suited for installation in high-rise buildings, hospitals, underground tunnels, school, steel factories, chemical plants and places where fire safety is a great concern. Hazard free to the environment, dry type transformers have over the years proven to be highly reliable.
Read Our Other Transformer Pages: Potential Transformer Explained, Control Transformer Explained, Current Transformer Basics, Current Transformer Explained, Isolation Transformer Explained, When To Use a Step Down Transformer