Method for remote adjusting of speeds of multiple direct current brushless motors

Provided is a method for remote adjusting of speeds of multiple direct current brushless motors. The method is achieved through a device composed of a rectification control unit and a plurality of speed adjusting units. The rectification control unit inputs a single-phase 220V alternating current power supply, and outputs a controllable rectification voltage after voltage reduction of a transformer. A speed control signal containing a motor operating direction and an operating speed grade is sent in the controllable rectification voltage. The speed control signal comprises a guiding wave composed of a rectification wave of a plurality of power frequency cycles and an alternating current wave of one power frequency cycle, and a data wave composed of a plurality of power frequency cycles. Each speed adjusting unit inputs the controllable rectification voltage containing the speed control signal, and controls a speed of a direct current brushless motor. In the method, a remote controller is not needed, individual laying of control lines is not needed, a speed is controlled directly by utilization of a transmission speed of a single-phase power supply line, and control and adjusting of speeds of multiple direct current brushless motors can be achieved.