What Are Bipolar Stepper Motors?

Stepper motor driving, unipolar and bipolar are the two most commonly used drive architectures for stepper motors. The unipolar drive circuit uses four transistors to drive the two phases of the stepper motor. The motor structure, as shown in Figure 1, includes two sets of coils with a center tap. The entire motor has six wires connected to the outside world. This type of motor is sometimes called a four-phase motor, but this term is confusing and incorrect, because it actually only has two phases. The precise description should be a two-phase six-wire stepping motor. Although the six-wire stepping motor is also called a unipolar stepping motor, it can actually use unipolar or bipolar driving circuits at the same time (the five-wire motor is also a four-phase motor, and the two neutral wires are connected to draw a line. ).