Evaluation of internal defects in squirrel cage rotor by novel Hall sensor technique

A nondestructive evaluation technique based on novel Hall sensor technique for detecting internal flaws in aluminum die-cast squirrel cage rotors has been developed. Electric currents are supplied to both sides of end-rings of the rotor and the variation of currents which flow in the bar of the rotor has been measured by the Hall sensor technique. Some signal processing techniques have been introduced to classify the signals due to the defects in the bars of the rotor from the measured signals. The effect of depth and size of artificial defect on the variation of signals has also been investigated