| 摘要 |
PURPOSE:To test insulation while rotating a commutator by using a long-sized conductive core body which has small crossing length as compared with the gap length between adjacent commutator pieces and insulating reinforced bodies which have almost the same hardness as that of the conductor core body. CONSTITUTION:A contactor body 20 consists of the plate type conductive core body 22 and a couple of plate type insulating reinforced bodies 24 which sandwich it from both top and reverse surfaces, and the thickness L1 of the core body 22 is small as compared with the gap length L2 between the adjacent commutator pieces 1a; and the reinforced bodies 24 are formed of materials which are almost as hard as the core body 22 and the core body 22 and reinforced materials 22 are adheered together. Then, end surfaces of a couple of contactors 10 are brought into contact with the top surfaces of the commutator pieces 1a while shifted by one commutator piece 1a and the deflection of the pointer of a tester is confirmed while the commutator is rotated. Here, the end surface of the core body 22 conducts only when positioned on the top surface of the commutator piece 1a, but does not conduct when on an insulating piece 1b on condition that insulation is normal; if there is a defect in insulation, deflection is confirmed, so the commutator is rotated slowly to find an insulating piece 1b having the defect in insulation. |
