An insulator is configured to couple to a top portion of a stator core and includes: a main body that has a ring shape; a plurality of insulating teeth that protrude toward a center portion of the main body and that are configured to couple to a plurality of teeth of the stator core, respectively; and a plurality of guide tabs that protrude from an outer circumferential surface of the main body at positions corresponding to the plurality of insulating teeth. The plurality of guide tabs are configured to guide (i) phase coils that are wound around the plurality of insulating teeth and (ii) neutral coils along the outer circumferential surface in a circumferential direction. Each of the plurality of guide tabs defines a plurality of guide grooves, each of the plurality of guide grooves being configured to seat at least one of the phase coils or the neutral coils.