PM is divided into two categories:

• Minor PM is basic maintenance and is simply the act of performing the fundamental equipment service (lubrication, cleaning, routine adjustments, etc.) essential to assure the operation of the equipment. The activity is quite simple with just a few machines, adequate downtime, and sufficient funds. A problem begins to occur when there are a lot of machines with no organized program to schedule and control the work tasks. The solution is to implement a minor Preventive Maintenance program to be certain that the machinery basics are addressed in a timely and efficient manner. Such a program becomes the minimum requirement but does nothing to anticipate potential failures.
• Major PM not only includes Minor PM but also begins to address potential failures. With this option, machinery is scheduled out of service so that more involved tasks can be performed. Based on run hours or some equivalent time factor, components such as bearings, shafts, sensors, gears, piping, etc., are replaced in anticipation of potential failure in the near future. The time factor is usually determined through experience and is statistical in nature. With this practice, it is possible to replace components that are still in good condition as well as run the risk of introducing a problem through improper maintenance. As a result, cost can sometimes increase without the benefit. However, both Minor and Major PM are critical to assuring equipment reliability and a combination of the two is frequently practiced.
  SpectraQuest provides consulting services to assess facility condition and implement PM practices.

Predictive Maintenance (PdM):
PdM is the monitoring and detection of machinery problems before they actually occur. This action costs more up front than PM because of the additional manning, tooling, and education required to establish a Predictive Maintenance program. However, it offers increased equipment reliability and sufficient advance information to improve planning, thereby reducing unexpected downtime and operating cost. Vibration monitoring, lubricant analysis, infrared thermographic surveys, motor current analysis, etc., are typical predictive techniques. These methods identify imminent bearing failures, shaft misalignment, balance problems, imminent motor failures, poor electrical terminations, etc. There are many techniques on the market with more being developed each year. A comprehensive PM and PdM program is the ultimate approach to assure machinery reliability.

Advantages:

• Assures equipment reliability.
• Assures maximum machinery availability.
• Assures that assets are maintained in optimum condition at maximum value.
• The cost of spare parts inventory can be reduced in some cases because of the ability to forecast failures sufficiently in advance to secure parts on an as needed basis.
• Can be used to assist in troubleshooting complex rotor dynamics issues.
• Evaluate the quality of equipment prior to purchase.
• Assures the quality of new equipment installation.
• Assures the quality of equipment repairs.
• Evaluate the condition of used machinery prior to purchase.
• Minimizes the potential for litigation due to equipment failure.

Disadvantages:

• The cost of supporting a PdM program is signification but hopefully offset by the advantages.
• The quality of PdM service is not assured. Many companies with in-house programs do not obtain the full benefit of PdM due to inadequate funding, training, tooling, etc. PdM contractors vary considerably in capability. Being of technical nature, it is very easy for the inexperience to award contracts to firms that cannot deliver quality service.
• Predictive Maintenance techniques do not always detect imminent failures.
  SpectraQuest provides vibration related PdM consulting services and training.