Maintaining the integrity of electrical equipment in a reliable manner is a task that seems difficult given that many of the failure modes in electrical components are random and unable to be detected through any form of condition monitoring.
It is possible to utilise thermography and impedance checks to detect failure modes in some components, mainly power components, however, it is more difficult to detect developing defects in electronic devices or enclosed equipment. The fortunate thing is that electrical components and electronic devices are usually designed to be very reliable and the random failure modes, while they will always occur, are not common if the electrical equipment integrity is maintained in a proactive manner. I.e. In a manner that will avoid or minimise the onset of these failure modes.
When maintaining mechanical equipment it is important to maintain it, Tight, Lubricated and Clean (TLC) in order to minimise the onset of failure modes that are due to looseness, poor lubrication or the effects of dirt. In the same manner, electrical equipment must be maintained Tight, Clean, Dry and Cool (TCDC) in order to minimise the onset of the most common failure modes. When electrical and electronic equipment is subject to vibration, dirt, moisture or heat, the integrity and longevity of the conductors and insulation are rapidly diminished. In fact, insulation life is reduced exponentially with increased operating temperatures.
With this in mind, it is essential that maintenance programs for electrical equipment are designed to include the following:
- Ensure that the equipment is always tightly mounted and free of looseness that can cause vibration. This is important to maintain over the longer term as mountings, especially vibration dampening mountings, deteriorate.
- Ensure that the equipment is always kept clean and dry. Electrical cabinets must be able to exclude the environmental elements outside. This sometimes requires positive pressure where the cabinets also require ventilation to remove heat generated by the electrical current. Keeping the equipment clean is a big part of keeping them cool.
From Bluefield experience, we find that these fundamental inspections and tasks for maintaining electrical equipment integrity, are often in place within the PM program. However, as equipment ages, we often find that the standards are allowed to deteriorate or even worse, maintenance activities allow the original component integrity which is designed to maintain a TCDC operating environment, to be defeated. Some example are below: