This part of JB/T 4279 specifies the verification content of the enameled circular wire disbonding tester, including verification items, technical requirements, verification equipment, methods of verification and result processing. Among them, it is specified that the distance between the two fixtures of the tester should be adjusted to 500mm +/- 5mm, the rotation speed of the sample torsion should be 60r/min~ 100r/min, the hanging rod and the load should be at least 25N, 40N, 60N, 100N, and the weight error range is +/- 10%. The verification apparatus includes a steel tape measure (2m), a stopwatch (scale interval 0.1s), an electronic scale or a scale (scale interval 5g). The method of verification includes a general inspection, which includes checking that the tester is placed horizontally, the slider can move smoothly on the guide rail, the fixture is free of loosening and displacement, the doctor blade is sharp and the two blades are parallel and not notched, and the torsion counter is reliable and free of counting errors.