An electric motor assembly and a rotor for an electric motor are provided. A rotor includes a yoke, and a plurality of magnets held by the yoke. The yoke is formed from a plurality of laminations. The yoke includes an inner peripheral surface surrounding a cavity. The inner peripheral surface has a plurality of rectangular cut-out sections that are each configured to receive a respective magnet of the plurality of magnets. The inner peripheral surface further includes a protrusion extending toward the cavity, and each protrusion having a flat surface facing the cavity.