Stepping motors are generally composed of front and rear end covers, bearings, central shafts, rotor cores, stator cores, stator assemblies, corrugated washers, screws, and other parts, and are driven by coils wound around the motor stator slots. Typically, a wire wound in a circle is called a solenoid, while in a motor, the wire wound around the stator slots is called a winding, coil, or phase. The different number of coils inside the motor has become the origin of our common two-phase stepper motor and three-phase stepper motor.
So what is the difference between a two-phase stepper motor and a three-phase stepper motor? What are the differences?
1. Number of phases of the motor
As just introduced in the construction of a stepping motor, the number of coils inside the motor is different, and the number of phases of the motor is also different. The inside of a two-phase stepping motor is composed of two coils, while the inside of a three-phase stepping motor is composed of three coils.
2. Step angle of the motor
The step angle refers to the viewpoint of each step taken by the motor. Currently, there are two types of step angles for two-phase stepper motors on the market: 0.9 °/1.8 °, and 1.2 ° for three-phase stepper motors. It is particularly suitable for applications that require higher accuracy or require smoother and quieter operation.
3. Dimensions of the motor
Three-phase stepper motors are generally large motors, so their dimensions are generally larger than those of two-phase stepper motors. This has become the inherent advantage of three-phase stepper motors, which are smaller torque fluctuations and smoother operation. There are also drawbacks, which are that the size is larger than that of the two phases, and the application site is very limited. Therefore, the most common typical application in the field of stage lighting is that the spotlight needs to move quickly, while requiring quiet operation without affecting performance.
The torque of a two-phase stepper motor with the same scale will be slightly larger than the torque of a three-phase motor. Many people don't understand why two-phase stepper motors are larger than three-phase ones. That's because the 0.9 ° step angle is smaller than 1.2 °. Under the same operating speed of the motor, the pulse frequency applied to the 0.9 ° stepper motor must be more than one time that of 1.2 °, so the torque generated is slightly larger than that of 1.2 °. A typical application of the 0.9 ° stepper motor is security cameras, which can make the camera operate smoothly and accurately, Without causing the camera to shake, thereby causing blurring of the image.
Due to the different phase numbers, the corresponding stepper drivers are also different. The subdivision functions of two-phase stepper motor drivers are becoming more and more sophisticated, and this difference has been made very small. Two-phase stepping motors can also achieve the accuracy that three-phase stepping motors can achieve, and the torque in high-speed sections is also very close.