CM and Class society

In the 'traditional' way of maintaining large installations, preventive maintenance is performed often. After the expiry of a specified calendar time or hours of an installation is made open and bearings and other wear parts are replaced as a precaution.

Corrective maintenance

Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out, to bring it back to working order. Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant. This form of maintenance is also called instant maintenance or destructive maintenance.

Preventive maintenance

With preventive maintenance, parts of a machine or system are replaced on base of calendar time or operating hours. The OEM indicates when a component needs to be replaced to avoid failure, and thus a maximum return on the asset is achieved. This way of maintenance is also called periodic maintenance.

Predictive maintenance

In predictive or condition-based maintenance, maintenance is performed on base of the actual condition of the machine or system. The condition is determined by periodic or continuous measurements (condition monitoring). This allows maintenance intervals to be extended, or the other way around, maintenance can be performed on a shorter than planned term to prevent early breakdown of a machine