In September 1821, English experimentalist Michael Faraday constructed a device demonstrating continuous motion driven by electromagnetic forces at the Royal Institution.

Apparatus & Physical Mechanism¶

Faraday immersed a permanent bar magnet vertically in a vessel of mercury. When an electric current passed through a suspended wire touching the mercury bath, the magnetic Lorentz force ($\mathbf{F} = I \mathbf{L} \times \mathbf{B}$) caused the wire to rotate continuously around the magnetic pole.

$$\mathbf{F}_{\text{magnetic}} = q (\mathbf{v} \times \mathbf{B})$$

Birth of Electric Motor Technology¶

Faraday’s electromagnetic rotator proved for the first time that electrical energy can be converted directly into continuous mechanical rotation.