Patent ID: 8118565

Claim:
A blower comprising: a fan; an air volume specifying circuit of the fan; a brushless DC motor that drives the fan; an inverter circuit of the brushless DC motor; a driving logic control circuit that performs driving control of the brushless DC motor; a number of revolutions detecting circuit that detects a number of revolutions of the brushless DC motor; a low-voltage direct-current power source that applies a low-voltage direct-current voltage to the inverter circuit; a supply current control circuit that controls an average current supplied to the inverter circuit; a current specifying circuit that specifies the average current, wherein the number of revolutions of the brushless DC motor is controlled by the current specifying circuit to maintain the air volume of the fan at a constant level, a specified number of revolutions storage circuit that stores a required number of revolutions of the brushless DC motor as a specified number of revolutions for every specified air volume and every specified current; and an air volume control circuit that selects a specified number of revolutions corresponding to the specified air volume and current from the specified number of revolutions storage circuit, and changes the average current specified by the current specifying circuit so that the number of revolutions of the brushless DC motor becomes the specified number of revolutions.