Infrared Thermography and Distribution System Maintenance

Mirant Mid-Atlantic’s condition-monitoring team consists of a central group of four technicians and one team leader. The team’s primary responsibilities are the company’s four coal-fired power plants; as resources and priorities permit, the team also provides support to other assets.

The IR camera is a great tool used in our everyday predictive maintenance endeavors, but it can play tricks on our eyes if we do not investigate beyond what we are observing. Things truly are not always as they seem, here's an example:

In today's industry, practices that were once acceptable are no longer even tolerated. Environmental concerns and EPA mandates are applying more and more pressure on businesses like the chemical industry to improve the manufacturing processes being used, to the point that not only is a slight drip from a pump seal not acceptable, but in 2004 the MACT will be enacted and only 500 - 1,000 parts per million vapor will be allowed and, eventually, no vapor at all.

It may seem that visual inspection goes beyond what thermographers are hired to do, but conscientious thermographers include notes and even images in their reports when they see code violations, broken equipment, incorrectly sized fuses, bad wiring, etc. A good thermographer will not ignore copper tubing used as a fuse, even if it looks fine in the infrared. Whether the inspection is insurance driven or a proactive stance, an infrared inspection and a visual inspection complement each other.

Infrared Thermal Imaging is an excellent condition monitoring tool to assist in the reduction of maintenance costs on mechanical equipment. The technique allows for the monitoring of temperatures and thermal patterns while the equipment is online and running under full load. Most mechanical equipment has allowable operating temperature limits that can be used as guidelines. Unlike many other test methods, Infrared Thermal Imaging can be used on a wide variety of equipment including pumps, motors, bearings, pulleys, fans, drives, conveyors etc.

The paper deals with the method of gearbox diagnostics fault detection, and shows that using: design, production technology, operational, change of condition (DPTOCC) factors analysis leads to the inference of gearbox diagnostic information. In the paper is a review of the current possibilities for using mathematical modeling and computer simulation for investigating the dynamic properties of gearbox systems. Computer simulation of dynamic behavior of gearboxes is a powerful tool for supporting gearbox diagnostic inference.

A shaft centerline diagram is a plot used in the vibration analysis of journal bearings. It is also called a shaft average centerline diagram. The purpose of this graph is to display the average position of the rotor in the bearing. In short, for different bearing types, there is an expected or “normal” position of the shaft in the bearing. If this position changes, it can indicate a problem.