Correction of transformer temperatures for variation in room temperature, taking into account both copper and iron losses

Assuming that loss of heat takes place only by convection, formulas are derived for obtaining the corrected temperature rise of a body consisting mainly of copper for any arbitrary room temperature. Similar formulas are derived for bodies consisting of both iron and copper. It is shown that when the effects of both the iron and copper loss in a transformer are taken into account, this correction is so small that it is of the same order as the probable errors of observation, and may generally be neglected. When other factors are considered, this correction is still further reduced. If the effect of radiation also be taken into account, the probable correction is reduced to zero, or may even be negative where the rules indicate positive corrections.