Coil of Barlow

The wheel of Barlow is the name of the one of the very first demonstrations of Electrical motor. She was imagined and implemented by the Mathématicien and Physicien English Peter Barlow in 1822. Its interest is only historical, taking into account its lack of power.

Example of the Wheel of Barlow functioning with only one thermo-electric element Paris: Ducretet, 1880

It is about a device allowing the description of the continuous rotation movements created by the electromagnetic forces.
This wheel functions with only one thermo-electric element, electric motor (very rare model, first electrical motor). This apparatus consists of a disc (or, as on the figure opposite, of a toothed wheel) in Cuivre which can turn vertically around a horizontal axis of which one of the pivots communicates with the pole of a Battery.

The disc plunges slightly in a small basin containing of the mercury which is connected to the other pole of the battery. Under these conditions, the disc is then crossed by a current which follows one of its rays. A Magnet, in the horseshoe shape, is laid out so that the ends of its two poles are located on both sides periphery of the disc.

The electromagnetic force which is exerted on the part of the disc traversed by the current finds in the plan even disc, on a ray perpendicular to the line magnetic of the magnet and perpendicular to the ray of the disc traversed by the current: it thus involves the disc towards outside (on the diagram opposite, towards the right-hand side or the left according to the direction of the current), thus tending to make it turn. Then, another ray of the disc succeeds at once the precedent and the rotation movement becomes continuous.

This apparatus constitutes to some extent a Electrical motor elementary founded on the electrodynamic actions of the current.

Barlow showed, according to the theories of Faraday, that the forces which the magnetic fields exert on the currents can bring rotation continues drivers.

External bond

Animation representing a model built by the Ducretet house in Paris about 1880.

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