Influence of Scanning Velocity and Gap Distance on Magnetic Flux Leakage Measurement
Noppadon Sumyong, Asa Prateepasen, and Pakorn Kaewtrakulpong

Abstract
This paper presents the development of a magnetic flux leakage instrument. Mechanical driving parts were introduced to improve the stability of the in- strument during the movement and to control constant scanning velocity. The effect on scanning velocity and gap distance between defects and coil sensors of the instrument were studied. In our experiments, various types of artificial defects were employed to investigate performance of the instrument. The results showed that the signal amplitude decreased when the gap distances and the scanning velocities increased. However, interaction effect between both parameters was also exhibited. Characteristic of the defect on
the signal output was also revealed.

Keywords: wire rope, magnetic flux leakage, gap distance, scanning velocity