The special requirements of rotor dynamics engineering are illustrated by means of different examples of turbomachines.The properties of magnetic bearings and the more common fluid film bearings are pointed out in the examples of two turbo compressors.The importance of the correct consideration of bearing support properties is shown for a turbine generator train.The impact of seal forces are demonstrated for the turbo compressor supported on fluid film bearings.Two of the considered seals are honeycomb seals.Bearings and seals can have frequency and speed dependent characteristics; complex supports have non-negligible couplings between bearings and are frequency dependent as well.The consequences of the coupling of lateral and torsional vibrations in gears are illustrated for a gear compressor with three pinions.All examples have a practical background from troubleshooting and engineering work although they do not exactly correspond to real cases.