Vibration Isolation Principals

Reducing vibrations emanating from a machine, plant or other vibration-emitting equipment is vital for a disturbance-free operation of the machine or plant itself, as well as for its surroundings. Conversely, it is important to reduce external vibrations influencing the machine.
Therefore a distinction is made between ACTIVE isolation (which protects the surroundings from vibrations emitted by a machine, and PASSIVE isolation (in which the machine or plant itself is protected from external interference).
Mounting a machine on a vibration-isolated bedding reduces amplitudes, resulting from shock excitation, to a permissible operational level. Damping plays an important role in this as it transforms mechanical energy into heat and thus limits the amplitudes to a permissible level. It is important to select a suitable vibration isolator in order to achieve the best possible isolation effect.
Firstly, it is necessary to consider the ratio between excitation and natural frequency:
Effective vibration isolation occurs when the above ratio exceeds the value >√2. If the value is smaller, it can result in excessive increase in interference. As a rule, the aim is to achieve a ratio between 3 and 4. For particular requirements, higher values may also be realized; however these have their limitations from both a technical and economic point of view. The isolation effectiveness is calculated as follows:
In general, four different types of isolators are employed at different and sometimes overlapping frequencies: