ZHOU Han-jie，JIN Chang-sheng，ZHENG Shu-hua，FANG Yin

（Hangzhou Steam Turbine Co.，Ltd.，Hangzhou 310012，China）

Abstract：Aiming at the vibration on the drive shaft side of wax oil hydrogenation turbine was too large to run normally when the steam turbine was in commissioning process in a refinery project and the shaft electrical run-out was also too large. The vibration spectrum and axis orbit of the turbine shaft were analyzed，and the shaft magnetism was test by using pin to approach rotor slowly，the pin was attracted， it was indicate that the rotor was magnetized. The principle of eddy current sensor，the eddy current sensor signal were influenced by themagnetic flux，and the relationship between eddy current sensor and the measured metal body were further investigated bymagnetoresistance effect theory，then the experimental model was established and simulated，and combined with engineering applications.The result indicates that the magnetic flux of rotor is over ANSI/API Std 612 standers and the vibration interference is influenced by theexcessive magnetic flux of rotor through theory analysis and experiment test. Then adopting degaussing and rolling countermeasures andsolving this problem，it is reference for other similar problems.

Key words：rotor magnetizing；eddy current sensor；magnetic flux；vibration interference