What Is a 2-Phase Stepper Motor?
A 2-phase stepper motor consists of two phases, A and B, and is a type of motor that precisely controls the rotational angle and speed with pulse signals. It operates by rotating a fixed angle with each pulse, similar to the second hand of a clock, known as the basic step angle. The motor’s structure allows magnetic poles to form each phase, affecting the control method and operational angle per pulse.
Applications of 2-Phase Stepper Motors
2-phase stepper motors are instrumental in various applications requiring precise motion control, including clocks, industrial machines, robots, printers, slot machines, and camera lenses. They excel in applications needing synchronized motion with pulse signals but are not suited for heavy-load environments.
Principle of 2-Phase Stepper Motors
Stepper motors operate on set rotational speeds over time, known as operation patterns. These include a self-starting operation for constant speed rotation and manual operation patterns for gradually increasing speeds, forming a trapezoidal speed versus time graph. Motor performance is influenced by its characteristics, the mass of the object, the power supply, and the wiring method.
Types of 2-Phase Stepper Motors
2-phase stepper motors vary in design and functionality:
1. VR Motor Type
Characterized by an iron rotor and multiple convex teeth on both rotor and stator, though less common today.
2. PM Motor Type
Features a permanent magnet rotor and stator windings at 90-degree intervals, with a limit of about 20 poles due to magnetization spacing.
3. HB Motor Type
Includes a cylindrical magnet on the shaft, with two rotors offset by half a pitch and stator windings arranged every 90 degrees.
Wiring Methods of 2-Phase Stepper Motors
The performance of 2-phase stepper motors significantly depends on the wiring method:
1. Bipolar Wiring: Allows current to flow in both directions through the motor windings, offering higher torque but requiring a more complex drive circuit.
2. Unipolar Wiring: Directs current in a constant direction through two windings, simplifying the drive circuit at the expense of reduced torque.