A rotating machine that converts mechanical energy into direct current electricity through electromagnetic induction. It uses a commutator and brushes to mechanically rectify the alternating current generated in the spinning armature into a pulsing direct current output. While largely replaced by alternators with solid-state rectifiers in heavy industry, the term is still used for small DC generators.
The exciter on this old hydro unit is essentially a DC dynamo coupled straight to the main shaft.
Also heard as
- DC generator
Do not mix it up with
- Alternator: A dynamo produces direct current using a mechanical commutator, while an alternator produces alternating current.
Related terms
Alternator
A generator that converts mechanical energy into alternating current.
Commutate
To reverse the direction of electric current in a specific winding or circuit branch.
Commutation
The process of transferring current from one conducting path to another.
Rotary converter
An early electromechanical machine used to convert alternating current to direct current.