A polyphase electric motor has a rotor, a stator with a plurality of slots, a plurality of main windings and a plurality of auxiliary windings installed in slots of the stator, and a main winding and an auxiliary winding that correspond to a selected phase of an alternating current power source. The auxiliary windings are connected to the motor terminals through a plurality of capacitors, and the auxiliary windings and corresponding capacitors are connected in parallel to the main windings. The main winding and the auxiliary winding of the selected phase are offset by about 60 to about 120 electrical degrees. A power of the plurality of main windings is at least 75% of a power of the polyphase electric motor at full load rating and the power of the plurality of main windings is motoring at 25% of the full load rating.