ClassX Video Lessons Youtube Channel The Engineering Mindset Types of Stepper Motor Explained – What are the different types?
Stepper motors are essential components in various applications, offering precise control over movement. Understanding the different types of stepper motors can help in selecting the right one for specific tasks. Let’s explore the three main types: permanent magnet, variable reluctance, and hybrid stepper motors.
The permanent magnet stepper motor is a straightforward design featuring a rotor made of a permanent magnet. This rotor is magnetized across its diameter. In a basic setup, the motor includes four coils arranged in two pairs, each connected to a separate phase. When one pair of coils is energized, the rotor aligns with the magnetic field created by the coils. As the next pair is energized, the rotor turns again to align with the new magnetic field. This process of energizing and de-energizing the coils continues, causing the rotor to rotate in 90-degree steps. Enhancements can be made by adding more coils or increasing the number of magnetic poles on the rotor, which can improve the motor’s resolution.
The variable reluctance stepper motor operates differently. It uses a rotor made of soft iron, which is attracted to magnetic fields but is not a permanent magnet. This design includes a rotor with four teeth and three sets of coils, each connected to a different phase. The differing number of coils and rotor teeth ensures that the rotor does not align all at once. The motor is controlled using three switches. When switch 2 is activated, the coils become magnetized, attracting the rotor teeth and causing rotation. This sequence continues with switches 3 and 1, turning the rotor in 30-degree steps. To achieve smaller step angles, additional phases and rotor teeth can be introduced.
The hybrid stepper motor is the most commonly used type, combining features of both the permanent magnet and variable reluctance motors. In a simplified version, it includes four coils connected in two pairs and a magnetized rotor with poles at opposite ends. The rotor also has three teeth on each magnetic pole. The differing number of teeth and coils prevents simultaneous alignment. When the coils are energized, they create north and south poles that interact with the rotor’s magnetic field. This interaction causes the rotor to rotate as the magnetic fields attract and repel the rotor’s teeth. Each step in this example is 30 degrees.
In more complex hybrid stepper motors, the design allows for greater precision. These motors have eight coils divided into two groups of four, with a rotor containing 50 teeth and a stator with 48 teeth. Energizing the coils creates magnetic fields that interact with the rotor’s permanent magnet, causing it to turn in 1.8-degree steps. Only the teeth nearest the north polarity stator coils align during each step, providing high precision and torque. The rotor’s permanent magnet ensures that its south pole teeth align with the stator’s north polarity coils and vice versa.
Understanding these stepper motor types can significantly enhance your knowledge of electrical and electronics engineering. For further learning, explore additional resources and videos on this topic.
Engage with an online simulation tool that allows you to visualize and manipulate the operation of different types of stepper motors. Experiment with changing parameters such as the number of coils, rotor teeth, and phases to see how these affect the motor’s performance. This hands-on activity will deepen your understanding of the mechanics behind each motor type.
Form small groups and assign each group a type of stepper motor: permanent magnet, variable reluctance, or hybrid. Research your assigned motor type in detail and prepare a short presentation to share with the class. Focus on the unique characteristics, advantages, and applications of your motor type. This collaborative activity will enhance your research and communication skills.
Using circuit design software, create a basic control circuit for one of the stepper motor types discussed. Implement features such as direction control and speed variation. This activity will help you apply theoretical knowledge to practical circuit design, reinforcing your understanding of motor control principles.
Analyze a real-world application of stepper motors in industries such as robotics, automotive, or consumer electronics. Identify the type of stepper motor used and justify its selection based on the application’s requirements. Present your findings in a written report. This activity will connect theoretical concepts to practical applications, enhancing your analytical skills.
Participate in a workshop where you can assemble and test a simple stepper motor setup. Work with components such as coils, rotors, and control circuits to build a functioning model. This hands-on experience will solidify your understanding of stepper motor construction and operation, providing a tangible link between theory and practice.
Here’s a sanitized version of the provided YouTube transcript:
—
The first type of stepper motor we will consider is the permanent magnet motor. This is a fairly simple design that consists of a permanent magnet rotor, which is diametrically magnetized. In this simplified version, we have four coils connected as two separate pairs, with each pair connected to a different phase. When pair one is energized, the magnet rotates to align with it. The next pair is energized, causing the rotor to turn and align again. The coils keep turning on and off, and the current flows in different directions to create rotation. In this design, the motor turns 90 degrees with each step. We could improve this with more coils or more magnetic poles on the rotor.
The variable reluctance stepper motor is a little different. This type uses a soft iron ferromagnetic rotor, which means this material is attracted to a magnetic field but is not a permanent magnet. In this design, we have four teeth on the rotor and three sets of coils, with each set connected to a different phase. Notice there are different numbers of coils and rotor teeth, which prevents the rotor from aligning all at the same time. In this case, we use three switches to control the motor. When switch 2 closes, the coils magnetize and attract the rotor teeth, causing it to turn. Then switch 3 closes, and the rotor turns again to align with the magnetic field. Finally, switch 1 closes, and the rotor turns. This sequence then repeats. In this design, the rotor turns 30 degrees with each step. There are multiple ways to reduce the step angle, for example, by adding a fourth phase and more teeth to the rotor.
The hybrid stepper motor is the most common version used. It is a hybrid because it combines the variable reluctance and the permanent magnet stepper motor. In this simplified version with four coils connected in two pairs, we have a magnetized rotor, meaning the poles are at opposite ends. The rotor has three teeth on each magnetic pole. There are different numbers of teeth and coils to prevent them from aligning all at the same time. When we energize the coils, they form north and south poles, which interact with the rotor’s permanent magnetic field. The rotor’s south pole tooth is repelled by the stator’s south pole and attracted to the stator’s north pole, while the rotor’s north pole tooth is repelled by the stator’s north pole and attracted to the stator’s south pole. This causes rotation. Then the next set of coils is energized, and the rotor’s magnetic field is again attracted and repelled by the stator coils, causing further rotation. This continues with different sets of coils being energized and the current reversing to change the polarity of the coils. In this example, each step is 30 degrees.
Now, when we look at a more complex hybrid stepper motor, we can see the same process happening but with greater precision. There are eight coils split into two groups of four. The rotor has 50 teeth, and the stator has 48 teeth. When the coils are energized, they create magnetic fields that interact with the rotor’s permanent magnet. Each time the coil polarity changes, it causes the rotor to turn one step, which in this case is 1.8 degrees. Notice that each time it turns, only the teeth nearest the north polarity stator coils align; all other rotor teeth do not. The rotor contains a permanent magnet that is magnetized, meaning the poles are at opposite ends. While the rotor’s south pole teeth align with the stator’s north polarity coils, the rotor’s north pole teeth align with the stator’s south polarity coils. This design provides very high precision and torque.
Check out one of the videos on screen now to continue learning about electrical and electronics engineering, and I’ll catch you there for the next lesson. Don’t forget to follow us on social media and visit the engineeringmindset.com.
—
This version maintains the technical content while removing any informal language or unnecessary filler.
Stepper – A type of motor that moves in discrete steps, allowing for precise control of angular position. – The stepper motor was used in the robotic arm to ensure accurate positioning of the components.
Motor – A device that converts electrical energy into mechanical energy to perform work. – The electric motor in the vehicle was designed to provide high efficiency and low emissions.
Rotor – The rotating part of an electrical machine, such as in a motor or generator, that interacts with the magnetic field to produce motion. – The rotor’s alignment with the stator is crucial for the optimal performance of the induction motor.
Coils – Wound loops of wire that create a magnetic field when an electric current passes through them. – The coils in the transformer were designed to handle high voltage levels efficiently.
Magnetic – Relating to or exhibiting magnetism, the force by which materials exert an attractive or repulsive force on other materials. – The magnetic properties of the material were tested to determine its suitability for use in the new sensor design.
Fields – Regions of space characterized by a physical quantity, such as magnetic or electric force, that has a value at every point. – The study of electromagnetic fields is essential for understanding how wireless communication systems operate.
Precision – The degree to which repeated measurements under unchanged conditions show the same results, crucial in engineering design and manufacturing. – The precision of the CNC machine allowed for the production of components with very tight tolerances.
Design – The process of creating a plan or convention for the construction of an object or system. – The design of the bridge incorporated advanced materials to enhance its durability and load-bearing capacity.
Phases – Distinct stages in a process or cycle, often referring to the different states of matter or stages in electrical waveforms. – The three phases of the power supply ensure a balanced load distribution in the industrial plant.
Torque – A measure of the force that can cause an object to rotate about an axis, crucial in mechanical systems. – The engine’s torque output was optimized to improve the vehicle’s acceleration and towing capacity.
