Officer detailed to run machine (9)
I believe the answer is:
generator
'machine' is the definition.
(generator is a kind of machine)
'officer detailed to run' is the wordplay.
'officer' becomes 'gen' (abbreviation for general).
'detailed' becomes 'erato' (I can't explain this - if you can you should believe this answer much more).
'to run' becomes 'r' (cricket abbreviation).
'gen'+'erato'+'r'='GENERATOR'
Can you help me to learn more?
(Other definitions for generator that I've seen before include "meant to be electrifying?" , "Existing in name only" , "It gives power" , "Dynamo or similar machine" , "Power source" .)