Which statement correctly describes a two-shaft gas turbine?

Which statement correctly describes a two-shaft gas turbine?

• A. It has the load turbine downstream from the compressor turbine
• B. It is always an open cycle
• C. It uses two shafts, geared together
• D. It is always regenerative

Answer: (C)

Two-shaft gas turbines are built with two separate rotating assemblies: one shaft carries the compressor and the high‑pressure turbine (the gas generator), and a second shaft carries the power turbine that drives the load. These two shafts are typically connected through a reduction gear so they can run at different speeds while still delivering torque to the output. That combination—two shafts with gearing between them—best describes a two-shaft design. The other statements aren’t defining features. The relative placement of a load turbine downstream of the compressor turbine isn’t a universal characteristic of two-shaft machines, and the cycle type isn’t fixed by having two shafts: you can have open-cycle or regenerative configurations, so it isn’t inherently regenerative.

Two-shaft gas turbines are built with two separate rotating assemblies: one shaft carries the compressor and the high‑pressure turbine (the gas generator), and a second shaft carries the power turbine that drives the load. These two shafts are typically connected through a reduction gear so they can run at different speeds while still delivering torque to the output. That combination—two shafts with gearing between them—best describes a two-shaft design.

The other statements aren’t defining features. The relative placement of a load turbine downstream of the compressor turbine isn’t a universal characteristic of two-shaft machines, and the cycle type isn’t fixed by having two shafts: you can have open-cycle or regenerative configurations, so it isn’t inherently regenerative.