Как шагает ШАГОВЫЙ ЭЛЕКТРОДВИГАТЕЛЬ?

Summary

The video explains the internal structure and operating principles of stepper motors. It starts with a simple conceptual model, explaining how alternating magnetic fields in the stator coils move the permanent magnet rotor in precise steps. It then delves into a real stepper motor, showing the intricacies of the rotor's dual gear design which allows for very precise microstepping. Overall, it provides great insight into stepper motor construction and operation, clearly explaining the concepts in an engaging and easy to understand format.

Takeaways

• 😀 The video explains how stepper motors work and what makes them so precise.
• 👉 Stepper motors have multiple poles that create magnetic fields to attract and rotate the rotor.
• 🤔 By alternating power between the coils, the rotor rotates in discrete and consistent steps.
• 🔎 The rotor often has "teeth" that align with poles on the stator for greater holding torque.
• 🤓 Microstepping divides steps into smaller increments for greater positioning precision.
• ⚙️ Drivers control the power to coils to enable microstepping through PWM signals.
• 🔧 Stepper motors have high holding torque so they don't need positioning sensors.
• 👍 Increasing the number of rotor and stator teeth enables more steps per revolution.
• ✏️ Geared steppers can increase torque without reducing step precision.
• 📣 Stepper motors are ideal for 3D printers, CNC machines, and robotics.

Q & A

What is a stepper motor and how does it work?

A stepper motor is a type of electric motor that moves in precise steps. It has a rotor with permanent magnets and a stator with electromagnets. By powering the electromagnets in a sequence, the rotor turns in precise steps.

Why are stepper motors useful for 3D printers?

Stepper motors provide very precise positioning and movement control without needing position sensors. This makes them ideal for moving the print head and build platform in 3D printers to create detailed prints.

What is a stepper motor driver and why is it needed?

A stepper motor driver controls the power sent to the motor coils to provide the sequencing needed to turn the rotor. It allows features like microstepping to increase positioning resolution.

What is microstepping?

Microstepping is a technique where the driver sequences power through the electromagnet coils to position the rotor between normal step positions. This divides the basic motor steps into many smaller microsteps.

How does the rotor design help the stepper motor hold position?

The geared dual-wheel rotor design allows multiple stator teeth to attract and secure the permanent magnets between the wheels in both directions of rotation. This provides excellent holding torque to lock the shaft.

Why don't stepper motors need rotational position sensors?

The predictable stepping action means controller can track the rotor position accurately just by counting steps. As long as steps aren't skipped, sensors aren't needed.

What causes noise in some stepper motor drivers?

Some drivers use PWM control signals in the audible frequency range, causing the motor coils to vibrate and emit noise.

How many full steps make one complete rotation in common stepper motors?

Most common motors, like those in 3D printers, provide 200 full steps per complete 360 degree rotation. Special high-resolution motors may provide 400 or more steps.

How much rotation occurs with each full step?

Motors with 200 steps divide the 360 degree circle into evenly-spaced increments of 1.8 degrees. So in these motors, each full step turns the shaft 1.8 degrees.

Why don't orbital sanders use stepper motors?

Stepper motors rotate in discrete steps rather than smoothly. This stepping motion would cause unpleasant vibrations in orbital sanders, where smooth and fluid rotation is required.