Starting system in Gas turbine

In addition to the components of the gas turbine, there are accessory systems such as the starting system, ignition system, lubrication system and cooling system for proper functioning and maintenance of the system.


 In order to start the assembly, a starter is used which can be a diesel engine or a generator that is directly coupled to the shaft of the compressor/turbine assembly. 
The functions of the starter are three fold. The starter is to rotate the generator so that it reaches a self sustaining speed and to drive the compressor to purge the inlet and exhaust ducts for the escape of any volatile gases before the ignition occurs.
 The starter is also used to rotate the gas generator after shutdown to facilitate cooling. For these purposes two starters are used. 
One of them is a high speed starter which is used for rotating the generator and the other is used for purging and cooling purposes which is of low speed.


 The gas generator can also be started by the help of the compressor which receives some amount of output from the compressor turbine. In case not mentioned before, a compressor turbine is used for running the compressor and a power turbine is used for running the external load. This is the case in industrial heavy gas turbines. In case of turbojets, a fan is used to supply continuous flow of air.

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