Specifying Diagnostic Tools for Predictive Maintenance
Specifying and purchasing the most appropriate diagnostic instruments is an important key to an effective predictive maintenance (PdM) system, but managers can face challenges in building support for such purchases. Buying a replacement for a burned-out motor is a no-brainer. But decision makers might view the purchase of PdM instruments as a luxury in tough economic times.
To gain acceptance of PdM tools, managers can use lower-cost strategies, such as renting a unit or buying a demo unit. Using the equipment to avert even one major safety threat, shutdown, or high-cost repair will enable managers to more effectively discuss the potential benefits of the technology in the next management presentation.
Managers can optimize their PdM programs by doing a Pareto analysis. With work orders arranged in descending order of maintenance dollars, the analysis will show that 80 percent of the department's money goes to maintain 20 percent of the assets — the area of biggest payback for PdM.
If rotating equipment is failing, a portable vibration analyzer will be a good investment. For some equipment, such as large turbines and generators, it is worth having a fixed unit installed to monitor the equipment's condition continuously.
If the problems relate to building roofs and exterior walls, infrared thermography can isolate leaks and energy losses.
One key to successfully specifying thermal imagers is sensitivity. An imager with 38 mK sensitivity is three times more sensitive than one with 100 mK, so applications that require the ability to detect small temperature changes, such as those involving HVAC equipment, require lower noise sensitivity and will cost more. Those that do not need high levels of sensitivity, such as security cameras, are available at a lower cost.
Managers also should discuss problems related to equipment downtime with the vendors of diagnostic equipment, including infrared imagers and DMMs. Such talks might turn up applications of these technologies managers had not considered and offer solutions to nagging, potentially costly maintenance headaches.
Thomas A. Westerkamp is a maintenance and engineering management consultant and president of the work management division of Westerkamp Group LLC.