Rotary engine (7)
I believe the answer is:
turbine
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">rotary engine</span>' is the definition.<br/ ><span class="explanation-format__explanation">(turbine is a kind of rotary engine)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for turbine that I've seen before include "Machine or motor for tribune" , "Source of power" , "Ruin bet (anag)" , "Power-generating machine" , "Machine generating power" .)