Electricity in motion.

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1866 Invention Machines & devices

Dynamos generate their own magnetic field

Samuel Alfred Varley · Werner von Siemens · Charles Wheatstone

When we knew

Timeline date1866

Samuel Alfred Varley, Werner von Siemens, and Charles Wheatstone independently developed self-excited dynamo principles that amplified residual magnetism into an efficient generating field.

Why it mattered

It removed the need for a separate magnetic source and made powerful economical generators practical.

What came before

Faraday's induction and early magnetos generated electricity but depended on permanent or externally supplied fields.

What came after

Industrial generation, lighting systems, motors, and central stations followed rapidly.

Memory anchor

The generator used some of its own output to strengthen itself.