An automatic pin identification method for the three-phase dc brushless motor

Since the three-phase dc brushless motor has been used broadly in the industry, we try to develop a specific apparatus to test its performance automatically, such as efficiency, running current, and maximum speed. However, the motor manufactured by the different company always owns different 11-pins assignments, which should be connected to the apparatus, such as three terminals of the windings and eight pins including the inputs and the outputs of three Hall devices in the motor. In order to let the motor be tested by the apparatus automatically and easily, this paper discloses a pin identification method. At first, we classify the windings and the Hall devices into different classes by comparing the impedances between pin and pin. Next, the orthogonal relations between back-emfs and Hall outputs can be used to identify the phase sequences of the windings and the Hall devices. Finally, the motor is locked at a stable position, and then we can distinguish the output polarity of any Hall device by its output sign.