At what rpm are the igniters secured?

The correct answer is 4,500 rpm, which is the typical operational threshold for securing igniters in gas turbine systems. Once the turbine reaches this speed, it indicates that stable combustion has been achieved, and the ignition source is no longer necessary for maintaining the flame. The turbine effectively relies on the sustained combustion process, ensuring that the engine operates efficiently and safely without the igniters.

Igniters are crucial during the initial startup phase to establish combustion, but as the engine accelerates and achieves the higher RPM, the combustion stability increases, allowing for the removal of the igniter's influence. This not only optimizes performance but also prevents unnecessary wear on the ignition system components. Understanding this aspect of gas turbine operation is vital for ensuring proper maintenance and operational protocols in such systems.