direct-current generator

A direct-current (DC) generator is a machine that converts mechanical energy into electricity with a unidirectional voltage and current. This conversion is achieved through electromagnetic induction, a principle discovered by Michael Faraday, where moving a magnet near a coil of wire induces an electric current.12

In a DC generator, voltage is induced in coils as the machine rotates, causing a changing magnetic field. This induced voltage is inherently alternating, but a mechanical switch called a commutator reverses connections at specific points in each rotation. This ensures the output voltage is unidirectional, though it may pulsate. Practical DC generators use multiple coils and a multi-bar commutator to produce a nearly constant output voltage, controlled by the rotor speed and magnetic flux.1

DC generators were historically important for tasks like charging batteries and in electrolytic systems. While largely replaced by alternators and rectifiers, they can still operate as motors, reversing power flow, which alternators cannot do without additional complex systems.1