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Steam turbine engine

In 1884 Parsons moved to Clarke, Chapman and Co., ship-engine manufacturers operating near Newcastle, where he became head of their electrical-equipment development. He used Regnault 's large collection of steam properties ("data of the physicists") to develop a turbine engine turning at 18,000 RPM in 1884 and immediately utilised the new engine to drive an electrical generator, which he also designed. Parsons' steam turbine made cheap and plentiful electricity possible and revolutionised marine transport and naval warfare.

Another type of steam turbine at the time, invented by Gustaf de Laval (1845–1913) in the 1880s, was an impulse design that subjected the mechanism to huge centrifugal forces and so had limited output due to the weakness of the materials available. Parsons explained in his 1911 Rede Lecture that his appreciation of the scaling issue led to his 1884 breakthrough on the compound steam turbine:

It seemed to me that moderate surface velocities and speeds of rotation were essential if the turbine motor was to receive general acceptance as a prime mover. I therefore decided to split up the fall in pressure of the steam into small fractional expansions over a large number of turbines in series, so that the velocity of the steam nowhere should be great...I was also anxious to avoid the well-known cutting action on metal of steam at high velocity.