What is a true statement about a gas turbine starting device?

• A. It is also called "barring gear"
• B. It must be an electric motor
• C. It keeps rotating the turbine shaft until the turbine is up to full load
• D. It is necessary for all gas turbines

Answer: (D)

Starting a gas turbine requires something to get the rotor turning from a standstill so the compressor can draw air and the combustor can ignite fuel. The starting device provides that initial motion, bringing the rotor up to speed so combustion can sustain rotation. In practice, this means the starter can be an electric motor, an air starter, or a hydraulic starter—the essential role is to get the turbine rotating to a speed where ignition and continuous operation are possible. Once the turbine reaches the required speed, fuel is introduced and the engine continues to accelerate toward full-load operation, with the starting device disengaged.

Barring gear is not the starting device; it’s used for slow, controlled rotation during maintenance and inspection, not for starting and accelerating the turbine. The starting device does not have to be electric—air or hydraulic starters are common. And the device’s job isn’t to keep rotating all the way to full load; it only brings the rotor up to speed, after which the engine’s own combustion sustains and completes the startup. Therefore, a starting device is necessary for all gas turbines.