2 - Technology Extends Man's Muscles

Abstract

This chapter describes the ways in which technology has extended to man's muscles. Although man is an extremely versatile creature, his size, his structure, and his muscles put severe limitations on his capabilities. These physiological limitations exclude man from many tasks but invariably when such situations arise, technology has been brought into play. The extension of man's capabilities is a primary role of technology. Man's muscle power has been extended by machines and mechanization. His brain has been augmented by the computer. The chapter also describes mechanism with reference to electric motors. The principle of operation of the d.c. motor is simply that of a reversed dynamo. Its operation relies simply on magnetic repulsion and attraction, and it can easily be demonstrated with the help of a compass needle and a bar magnet. The commonest form of a.c. motor is the induction motor. Its action depends on the fact that a moving magnetic field can set a neighboring conductor into motion. In the large induction motor, the moving magnetic field is achieved in the following way: three pairs of fixed electromagnets are spaced at equal angles round a conducting motor, and each pair is connected to one of the phases of a three-phase supply.