Secondary Motors

Most of the ancient secondary motors, before the invention of thermal engines and electric motors, were spring motors since they were based on the principle that mechanical energy could be “stored” by the deformation of a flexible element.

For the Greeks any device that caused another object to move was a motor; this same criterion was used later by the Romans without any alteration. The first motor was the wind as it drove the sails and the water that dragged and pulled tree trunks in its wake as described in Chapter 5. Later, counterweights were devised using the same system as that used to raise sails and that was later applied to theatrical curtains as it was noted about gravity driven motors in Chapter 10. The observation of the movement of tow ropes and of sails as they were pulled taut led to other motors powered by the potential elastic energy of flexion and torsion.