What does TIR measure in rotating equipment?

• A. The uniformity of temperature across a surface
• B. The difference in diameter of a rotating part
• C. The difference between maximum and minimum readings
• D. The average wear over time of a component

Answer: (C)

TIR, or Total Indicator Runout, is a measurement used in rotating equipment to assess the precision and quality of a rotating component. It specifically measures the deviation from a perfect circular path as the component rotates. This is expressed as the difference between the maximum and minimum readings taken at various points during a full rotation.

When evaluating a rotating part, measuring TIR helps identify misalignment, imbalance, and wear that could affect performance and reliability. By calculating this difference, inspectors can assess the level of deviation from the ideal motion, which is crucial in ensuring the equipment operates smoothly and efficiently.

Understanding TIR is fundamental for maintenance and troubleshooting in rotating equipment, as it provides a clear indicator of how much a part strays from its intended rotational path, which can lead to increased wear or failure if not addressed.