Condition Monitoring of SIEMENS SGT-400 SGT-400 gas turbine Vibration Analysis- Orbit- Shaft Center Line- Twin-shaft gas turbine- Suitable for both power generation and mechanical drive applications-10-15 MW power band Image Source: www.siemens-energy.com ISO 20816-4:2018 Mechanical vibration — Measurement and evaluation of machine vibration — Part 4: Gas turbines in excess of 3 MW, with fluid-film bearings