Abstract: Unwanted vibrations in rotating machinery are controlled from an "active" point of view, meaning, that certain parameters, and thereby vibrations, can be controlled while the machine is operating. This is accomplished from the theoretical knowledge known about rotor dynamics, mechanical vibrations, automatic controls, fluid dynamics, and bearing design theory to produce an active remedy to fundamental vibration problems. From the known information about the critical speeds of a machine and while the speed transients are occuring, active controls cause these critical speeds to be made variable and always away from the actual running speed. By this means, the machine does not have to "run through" the critical speeds but rather, the critical speeds are jumped over by control of certain parameters. This approach is novel but may be accomplished by several different techniques, of which a variety are presented herein.