Analysis of Transient Loading and Heating of the Electronic Transformer

Electronic transformers are often subject to intermittent or transient electrical loading. As a consequence there are a variety of thermal waveforms which alter, in differing degrees, the aging rate of the transformer. First we define certain basic parameters--the thermal time constant, duty ratio, and relative aging. Various load waveshapes are described. We then see how the concept of relative aging can be employed so as to permit us either to increase the steady-state VA rating or to reduce the size of the electronic transformer, without jeopardizing its life expect- ancy.