The definition of Steam Turbine by Garham is "The Turbine is a Prime Mover in which a Rotary Motion is obtained by Centrifugal Force brought into action by changing the direction of a Jet a fluid escaping from a Nozzle at high Velocity".
The Turbine is an ideal Prime Mover and has got a variety of uses.It is used for driving Electric Generators and Ship Propellers in large size and in smaller size,it is adaptable for driving Pumps,Fans,Compressors etc.Then Steam Turbine is well adapted for work which requires high rotative and constant speeds even with widely fluctuating loads.
Advantages of the Steam Turbine over Reciprocating Engine.
01)Thermal Efficiency of a Steam Turbine is higher than that of a Reciprocating Engine.
02)The Steam Turbine develops power at a uniform rate and hence does not required Flywheel.
03)No internal lubrication is required for Steam Turbine as there is no rubbing parts inside.
04)No heavy foundation is required for Turbine because of the perfect balancing of the different parts.
05)If the Steam Turbine is properly designed and constructed then it is the most durable Prime Mover.
06)Much higher speed may be developed and a far grater range of speed is possible than in the case of Reciprocating Engine.
07)There are some frictional losses in Reciprocating Engine as some arrangements are required for conversion of Reciprocating Motion into circular motion.But in Steam Turbine no friction losses are there.
08)Steam Turbine are quite suitable for large Thermal Power Plant as they can be built in size from few Horse Power to over 200000 HP in single unit.