Steam Turbine is a device for converting energy of high-pressure steam produced in a boiler into mechanical power which can then be used to generate electricity. Steam turbines have been playing crucial role since The Industrial Revolution. Today, steam turbines contribute to most the world's electricity.

Turbine Unit
Roughly, it is conical, steel shell enclosing a central shaft that bears a series of bladed disks arranged in a queue. The blades are curved and extend radially outward from the rim of each disk. In some steam turbines the shaft is surrounded by a drum to which the rows of blades are attached. Between each pair of disks is a row of stationary vanes attached to the steel shell extending radially inward. Each set of stationary vanes and the bladed disk immediately next to it constitutes a stage of the turbine; most steam turbines are multistage engines.

Working Principle
The basic principle of Turbine is to convert mechanical energy most probably into electrical energy. And the working involves the force of pressurised steam that rotates the blades of turbine. The steam comes from a boiler it propels the blades to rotate, on exhaustion it is condensed and pumped back to the boiler to create a continuous cycle. Practically a large steam turbine consists of several turbines.

Applications
These have been the most important prime-mover for power generation. Turbines mainly serve a variety of industrial purposes comprising of large electric generators, pumps, and compressors in utilities and other process industries.