INSULATOR, STATOR, AND ROTATING ELECTRICAL MACHINE

An insulator according to an embodiment is attached to teeth extending from one side surface in a radial direction of a ring-shaped stator core in the radial direction. The insulator according to the embodiment ensures insulation between the teeth and a rectangular wire wound around the teeth with a number of windings. The insulator according to the embodiment includes an end-surface cover portion, two side-surface cover portions, a first wall portion, a second wall portion, a protruding-stripe portion, and a recess. The end-surface cover portion covers an end surface of the teeth in an axial direction. The two side-surface cover portions cover both side surfaces of the teeth in a circumferential direction. At one side-surface cover portion of the two side-surface cover portions, a first winding of the rectangular wire is disposed, the rectangular wire is wound around the teeth with a number of windings, and the protruding-stripe portion and the recess are formed.