dynamo
In a technical sense, this term refers to a specific type of electrical generator that produces direct current. It evokes an image of industrial power and the mechanical conversion of motion into electricity. When applied to a person, the word carries a highly positive connotation of tireless ambition and vitality. It describes someone whose energy is infectious and driving, acting as a catalyst for progress or change within a group or organization.
Meanings
A machine that converts mechanical energy into electrical energy by means of a rotating coil in a magnetic field.
"The old bicycle was equipped with a small dynamo to power the headlight."
A person who possesses an extraordinary amount of energy, drive, and enthusiasm.
"The new marketing director is a real dynamo who has completely revitalized the department."