3. Maintenance costs

The need for maintenance can result from several causes:

• normal wear and tear ;

• fatigue of elements subjected to erratic stresses ;

• deterioration of components in unforeseen circumstances.

• Normal or programmed wear

  Most components are designed for a service life of around 50,000 h, or 7 years of continuous operation (gears, bearings). Their maintenance is predictable, although the components to be replaced are not very costly; the...