Description This is a DC7V-12V Brushless Motor Driver Controller Board For Hard Drive Motor 3/4 Wire. The driver board has voltage reverse connection protection, over-current protection, short circuit protection, simple wiring, and worry-free use. The hard disk motor can be rotated at a voltage of 7-12V. The higher the voltage, the faster the speed, which can reach about 10,000 revolutions. How to identify the common port of a 4-wire motor: Measure the four terminals with the resistance x 1 of the meter. One of the terminals and the other three terminals have the smallest and equal resistance, then this terminal is the COM terminal, Which is the common terminal. The driver board automatically recognizes the 3-wire or 4-wire brushless motor, and the 4-wire brushless motor can also be disconnected from the COM line.