Final answer:
Steam and gas turbine rotors ride on a thin oil cushion, can exceed 20 tons in weight, and rotate at various speeds depending on their design.
Step-by-step explanation:
The rotors on steam and gas turbines are critical components that transform kinetic energy from a flow of air, water, or steam into mechanical energy for producing electricity. These turbines can be massive in size, with the largest ones featuring rotors of up to 150 meters in diameter and rated for as much as 10 MW of electrical power production. To operate efficiently and avoid wear and tear from metal-to-metal contact, these rotors ride on a cushion of oil so thin that it's comparable to the thickness of a human hair. Moreover, the weight of these rotors can be substantial, sometimes exceeding 20 tons, and they rotate at various speeds depending on the design, which can be much more than 1000 rpm, supported by journal bearings.