INSULATION DETERIORATION DETECTING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a method for detecting deterioration due to discharge on a coil surface or an insulating layer near it. SOLUTION: Hydrogen ion concentration test paper 21, fixed on an adhesive tape 22 for fixation after being impregnated with about 40 mg pure water is pressed for about 20 seconds against the surface of a slot exit part 3 of a coil 11 of an induction motor stator 1. Since the hydrogen ion concentration test paper 21 discolors according to the acidity of matter adhering on the surface of the coil 11, the ion concentration (pH value) of the adhered matter is measured by contrasting the color with a discoloration table to evaluate the degree of discharge deterioration.