Brushless motor and control method

A control method, comprising:

• using a brushless motor that comprises:
• a stator having a three-phase winding;
• a rotor that has a permanent magnet and that is rotated in a state of facing the stator;
• an inverter that has a plurality of switching elements and that supplies an AC current to the three-phase wiring by turning on or turning off the plurality of switching elements;
• and
• a control part that controls an ON or OFF state of the plurality of switching elements by switching a power distribution pattern that represents a change of a power distribution state of each phase of the three-phase wiring in response to a rotation of the rotor to a low-speed power distribution pattern in use for a low-speed power distribution control or a high-speed power distribution pattern in use for a high-speed power distribution control, the method comprising:
• by way of the control part, switching the power distribution pattern to the low-speed power distribution pattern in a case where a rotation speed of the rotor is less than a predetermined threshold value;
• and switching the power distribution pattern to the high-speed power distribution pattern when a state in which a load of the rotor is within a predetermined range is continued for a predetermined period of time in a case where the rotation speed of the rotor is equal to or more than the threshold value.