Which of the devices listed is commonly used to compensate for the expansion and minor misalignments occurring between the main turbine rotor and the reduction gear?

Correct Answer: Option B — Gear type flexible coupling

Gear-type flexible couplings utilize internal and external gear teeth with crowned profiles to accommodate axial thermal expansion and minor angular or parallel misalignments between the high-speed turbine rotor and the reduction gear pinion without imposing destructive bending moments.