Ventilated transformers are 150C rise, and Hard-shell units are 115C rise. Why are the Hardshell units so much warmer to the touch?
A. Ventilated transformers are free standing devices placed in a metal housing to protect the unit from the atmosphere, and people from electrical hazards. Ventilated units are surrounded by air, which acts as a cooling medium. The natural convection created by the heat of the transformer causes heat to ventilate through the top of the unit while cool air is drawn in from the bottom (chimney effect). Hardshell are placed in an enclosure that is filled with electrical grade sand and epoxy. All the air is displaced within this solid epoxy block, so any heat is radiated directly to the enclosure surface. This makes the entire enclosure of the transformer act like a heat sink. All SolaHD enclosed transformers are UL and CSA listed, your guarantee that the surface temperatures will not rise more than 50C above ambient.
