7. Diagnostic and monitoring methods

7.1 Special features of SEM equipment

The impossibility of verifying the internal state of the equipment, without fairly complex interventions requiring several hours or days out of service, has led to the search for non-intrusive diagnostic methods, or those that are quicker than complete dismantling.

Some can be used as continuous preventive monitoring, while others are more suited to a one-off examination which, depending on their relevance, cost and the user's maintenance policy, can be applied systematically or conditionally.

• Despite all the precautions taken during manufacture and assembly, including dielectric strength tests, defects, either original defects or changes due to the effect of voltage or current,...