Long-distance speed control system for brushless DC motor of fan

A long-distance speed control system for a brushless DC (direct current) motor of a fan, the fan having a motor, the motor being a brushless DC motor, the long-distance speed control system comprising:

• a mains power supply, being an AC (alternating-current) power supply and outputting a first power signal;
• a switch, electrically connected to the mains power supply to receive and transmit the first power signal, the switch having a plurality of variable speed positions for controlling a rotational speed of the motor, the speed positions being defined as a highest speed position, a plurality of speed control positions and an off position according to the rotational speed of the motor from high to low and stop, respectively;
• a switch circuit, having a plurality of components and a first node, the components each having an input terminal and an output terminal, the speed positions of the switch being selectively, electrically connected to the input terminals of the components, the output terminals of the components being electrically connected to the first node, the components of the switch circuit respectively receiving the first power signal to output a switching signal, the components being defined as a first wire and a plurality of capacitor banks respectively, the highest speed position of the switch corresponding to the first wire, the speed control positions of the switch corresponding to the capacitor banks respectively, the speed control positions of the switch, arranged according to the rotational speed of the motor from high to low corresponding to the capacitor banks arranged in descending order of capacitance respectively, the capacitor banks each having at least one capacitor, the capacitance of each capacitor bank being different, the first power signal being not adjusted through the first power signal passing through the first wire of the components or a voltage of the first power signal being reduced through the first power signal passing through the capacitor banks of the components for the switch circuit to output the switching signal;
• a voltage detection module, electrically connected to the first node of the switch circuit for the voltage detection module to receive the switching signal, the voltage detection module being configured to detect, judge and process the switching signal and to detect and judge a voltage of the switching signal for outputting a voltage detection signal, the voltage detection module further outputting a second power signal;
• a processing unit, electrically connected to the voltage detection module, the processing unit being receiving the voltage detection signal, the processing unit outputting a speed control signal according to the voltage detection signal;
• a drive unit, electrically connected to the processing unit, the voltage detection module and the motor of the fan, the drive unit receiving the speed control signal and the second power signal, the drive unit controlling the motor of the fan to turn on, turn off, and regulate the rotational speed according to the speed control signal and the second power signal.