In a world like that of Automation, where often our eye is more attentive to news, latest discoveries, and revolutionary solutions, we can happen to forget that even those devices which are now commonly used, the ones we consider to be dull and trivial, were once the news of the day - and that taking them to market took time, effort, and inventiveness. Today, we shall trace the steps which brought to the invention and marketing of a device which currently has a worldwide presence: the electric motor.
The word "electric", just like "electricity", comes from "elektron", the greek name of amber - and from the phenomenon by which, after a piece of amber is rubbed, it can (being now charged with static electricity) attract tiny pieces of paper: a simple trick, armchair Physics. And all of the first experiments on the power of electricity have this connotation of being little more than toys - including the first ancestor of the electric motor, which we can date at 1821 - the work of the famous British scientist, Michael Faraday. Nothing could be simpler: it's just composed of a magnet immersed in mercury, and of a copper wire, hanging above the container, which touches the mercury and moves, apparently by itself, along the lines of the field generated by the magnet itself. But the basic principles of an electric motor are already present, and only seven years later, in 1828, in Hungary,
Anyos Jedlik, scholar and teacher, builds his "Lightning-Magnetic Self-Rotor"
, the first device to contain the essential components - rotor, stator and commutator - of a real direct current electric motor.
As we have mentioned, at this point, we're still looking at curiosities, at simple toys: but ideas are fast runners. Five more years pass, and in England, Sturgeon builds the first electric motor with enough power to move real machinery, and five years later, in the United States, the first electric motor specifically designed for commercial purposes appears. It is the work of Emily and Thomas Davenport; it revolves at 600 rpm, and its purpose is moving machine tools and printing presses. It's a good idea - but the system isn't ready: namely, there is no distribution network for electric power, and supply is dependent on batteries equipped with expensive zinc electrodes - too expensive for a beginning market. The Davenports' project fails, and the progress of electric motors is arrested for almost thirty years - with the notable exception of a return, in 1855, by our friend Jedlik, who invents and builds the first electric motor-powered vehicle.
But time moves inexorably, and in 1873, the Belgian Zenobe Gramme makes a revolutionary discovery. His improved dynamo, known as the Gramme Machine, isn't just more efficient than other existing dynamos, but more importantly, it's reversible: by spinning, it generates electricity... but if it is FED electricity, it spins! And this is the essential principle of an electric motor - so much that, nowadays, all modern electric motors are structural descendants of the Gramme Machine.
From here on, the road is open, and less than fifteen years later, in 1886, Frank Julian Sprague can develop the first electric motor capable of mantaining constant speed with a variable load, and, no less important, of returning power to the main supply system. Besides its immediate practical applications, this is an invention which is, like few others, a hidden protagonist of the evolution of our culture, namely of urbanization: Sprague's motor allowed for the building of Chicago's elevated railway, the "L", and even more importantly to build practical elevators, which made skyscrapers feasible and functional - a fact which changed forever the way city buildings are designed. Just two years later, thanks to the work of that extraordinary figure in the history of electricity which was Nikola Tesla, the first AC motor will be built. The rest, as they say, is history.
