Rotordynamic effects in electrical machines become particularly relevant at high rotational speeds, or with specific bearing arrangements. The term mainly describes torsional or lateral vibrations of the machine rotor including a coupling to the electromagnetic domain. Housing vibrations, as they are investigated frequently are not in the scope of this contribution. Besides noise, rotordynamic effects may increase wear and reduce the lifetime of equipment or even lead to catastrophic failure. The involved phenomena have been described in various publications, through experiments, analytical modelling and numerical simulation. Besides effects due to manufacturing tolerances or mechanical and magnetic imbalances, also self-excited oscillations due to induction effects can play a role. This contribution aims at summarizing the main influence factors on the occurrence of these phenomena, restricting the scope to synchronous- and asynchronous machines, which resemble a large portion of systems used today. Aiming at a modelling approach to describe their transient behaviour under the earlier mentioned conditions, potential approaches are discussed, and a focus is set on important aspects of their numerical simulation as an extension to earlier works. Furthermore, an outlook on current challenges in the field will be given.