7. Conclusion

Only by accurately estimating costs in the light of the objective to be achieved can an appropriate maintenance policy be chosen. For industrial motors, condition-based maintenance tools are not yet widely used, and are very difficult to adapt to existing machines. As a result, systematic maintenance is still the dominant policy. However, predictive maintenance tools are developing, such as continuous monitoring of maximum cylinder pressures or coupling sag. Environmental constraints on pollutant emissions from thermal machines can also provide interesting tools for predictive maintenance, such as the continuous analysis of certain exhaust gas constituents.