Another small efficient matching transformer for an EFHW – 2643251002 – #2 – prototype bench measurement continued the development of a transformer design. This article presents thermal measurements.
Losses were predicted from a model as follows.
Loss in watts is in red against the right hand axis. Loss is greatest at around 3.6MHz, so it will be measured there. Expected loss is about 4.3W @ 3.6MHz running 50W through power.
Above, temperature rise is estimated to be about 36° under those conditions.
Above is a thermograph of the inductor in free air showing 43.7-12.2=31.5° rise over ambient, fairly stabilised after 8m of continuous 3.5MHz 50W carrier through signal.