dynamo; electric generator
Refers to a device that converts mechanical energy into electrical energy, especially a direct-current generator. Also used metaphorically for an energetic person.
自転車のライトはダイナモで点く。
The bicycle light is powered by a dynamo.
彼はチーム
He is the dynamo of the team.
Borrowed from English 'dynamo', ultimately from Greek 'dynamis' (power).