Choosing the Right Stepper Motor: PM Stepper or Hybrid Stepper?

Stepper motors are widely used in various applications that require precise control of motion, such as in robotics, 3D printing, CNC machines, and medical equipment. There are two main types of stepper motors: Permanent Magnet (PM) stepper motors and Hybrid stepper motors. In this article, we will discuss the differences, advantages, and when to use a PM stepper motor or a Hybrid stepper motor.

Permanent Magnet stepper motors, also known as "tin can" stepper motors, are the simplest type of stepper motor. They consist of a rotor with permanent magnets and a stator with two coils. When current is applied to one of the coils, it generates a magnetic field that attracts the permanent magnet rotor towards it. PM stepper motors are typically less expensive and simpler in design than hybrid stepper motors.

• Lower Cost: PM stepper motors are less expensive than hybrid stepper motors, making them a good choice for applications where cost is a major consideration.
• Simpler Design: PM stepper motors have a simpler design than hybrid stepper motors, making them easier to manufacture and maintain.
• Good Low-Speed Performance: PM stepper motors provide good low-speed performance, making them ideal for applications that require position control at low speeds.

Hybrid stepper motors are more complex than PM stepper motors. They typically use a sintered magnet which provides a higher magnetic flux over bonded magnets used in PM motors. They also include laminated stacks with precise teeth profiles in the rotor and stator that can create smaller step sizes. When the coils are energized, the rotor teeth are magnetically attracted to the stator teeth and move incrementally according to its natural step size. This furthers their ability to provide more precise control of the motor’s movement. 

• High Torque: Hybrid stepper motors provide high torque output, making them ideal for applications moving large loads. 
• Precise Positioning: Hybrid steppers can have a step size of 0.45°, making them great for precise positioning.
• Repeatable Movement: Hybrid steppers have very repeatable movement, making them perfect for applications with repetitive motions.

Hybrid stepper motors are suitable for applications that require high torque output where space is limited. Their high holding torque can maintain position without the use of a brake, and their small step size allows for precise positioning. Even without the use of a position feedback sensor, stepper motors can reliably achieve repetitive motions with a high level of accuracy.

While both PM stepper and hybrid stepper motors can move in increments, PM stepper motors have a simpler design while hybrid stepper motors offer a smaller step size and higher torque density. When choosing between a PM stepper motor and a hybrid stepper motor, there are several factors to consider:

PM stepper motors and Hybrid stepper motors are two main types of stepper motors used in a variety of applications that require precise control of motion. While PM stepper motors are simpler and less expensive, hybrid stepper motors provide higher torque output and can operate at higher speeds. 

When choosing a stepper motor, one should review the specific requirements of the application. Factors such as cost, torque, speed, precision, load, and control should be considered to ensure the right type of stepper motor is selected for the application.