抄録
This paper presents the deformation and fracture behaviors of stator windings subjected to bending moment. The experiments were carried out on four kinds of model windings, which were made with steel solid bar and copper strands and were impregnated with epoxy and polyester resins. The strain produced on the insulation surface and the deflection were measured under a uniform bending moment. The tangent delta characteristic was also measured and the occurrence of mechanical damages was discussed in relation to the variations in the tangent delta characteristic. The results obtained are as follows.
(1) Stator windings impregnated with epoxy resin begin to break when the tensile strain on the insulation surface reaches to the ultimate strain of the insulation.
(2) Stator windings impregnated with polyester resin are damaged on the compression side even at a very small strain level. Beyond a certain tensile strain, this failure accompanies the failure on the tension side.
(3) The test method, by which the tangent delta characteristic is measured in addition to the measurement of strain and deformation, is effective for the study of the failure mechanisms of composite materials as well as stator windings.
(4) It is considered that the use of an impregnating resin with higher mechanical strength is one of the useful means to get higher bending strength of stator windings.
