Laithwaite, Eric Roberts (1921– )

English electrical engineer who developed the linear motor. The idea of a linear induction motor had been suggested in 1895, but Laithwaite discovered that it is possible to arrange two linear motors back to back, so as to produce continuous oscillation without the use of any switching device.

Laithwaite was born in Yorkshire. He studied at the University of Manchester and, apart from the interruption of World War II, remained there until 1964, when he became professor of heavy electrical engineering at the Imperial College of Science and Technology at the University of London, moving to the Royal Institution 1967–76. He made many popular radio and television broadcasts.

The important feature of the linear motor is that it is a means of propulsion without the need for wheels, although often continuous motion has to be made up from reciprocating motion – achieved by the use of a ratchet, for example.

Linear motion is very common in industrial processes. In 1947 Laithwaite began research into electric linear induction motors as the shuttle drives in weaving looms, and later into the use of linear motors for conveyors and as propulsion units for high-speed railway vehicles moving on air cushions.