The world of automation is at its peak, things are changing rapidly in the electro-mechanical field and stepper motor and the servo motors are the base of all these changes.
These motor rotates in steps in a controlled manner and most importantly, this precise motion of the shaft is achieved without using any feedback system. Isn’t it interesting? But what do you think is the thing that does all this? In this tutorial, we are going to discuss only that topic.
What Is Stepper Motor?
As you know, the stepper motor is the type of DC the motor that converts electrical pulses into stepwise mechanical motion of the shaft.
Unlike other DC motors, this motor has a permanent magnet rotor that operates when the stator is energized. The construction of the stator is similar to a normal DC motor. The only difference is that the stator of this type of motor has mechanical teeth. These teeth align with the teeth of the rotor, after imparting pulses generated by the microcontroller to the stator.
The sequence of the pulse generated by the microcontroller allows the shaft of the motor to rotate in discrete steps. This motor uses a certain amount of such pulses to complete one round, these pulses are also responsible for controlling the speed of the motor. Increasing the frequency of input pulses allows the motor shaft rotation speed to increase.
The following picture shows the internal construction of the stepper motor.
Advantages Of The Stepper Motor:
Life of The Stepper Motor
If we examine the construction of the stepper motor, we will see that there is no friction in the moving parts except this bearing, so this is the reason the stepper motor survives for a long time. But again, motor use matters. The life of any motor depends on how we use the motor. More rigorous use of the motor can affect the life of the motor.
Holding Torque Of The Stepper Motor
Holding Torque of any motor is a really important parameter. It should be as high as possible.
Holding Torque is the motor’s ability to maintain its original position after energizing the motor windings, even when a large amount of force is applied to the shaft of the motor.
It is also known as the stand stall torque of the motor. On top of this, the stepper motor has another capability that keeps the rotor in the same position when no current flows through the winding and this is called the Detent Torque of the motor.
Maintenance Cost Of The Stepper Motor
Unlike other motors, this type of motor will not increase your expenses on maintenance costs and the reason for this is that the stepper motor is a brushless type of motor. Unlike other motors, in this motors, you do not need to change the brush repeatedly. And so we can say that the this type of motor has a low maintenance cost.
Repeatability Of The Stepper Motor
This is one of the best features of the stepper motor. The stepper motor has the ability to return to its original position after completing a full detour. This feature of this type of motors makes them more accurate and most useful motors in applications where precise speed is the priority.
5) Excellent Low Speed Torque
Stepper motors produce high torque at low speed. This makes it more suitable for applications where high torque is required with high precision
Cost And Complexity Of The Stepper Motor
If you are looking for a motor that controls the object more accurately then this is the best option for you. As we discussed, the stepper motor operates on an open-loop system, which means, unlike other motors, the stepper motor does not require an encoder and this makes the stepper motor less complex and inexpensive than other motors.
Disadvantages of The Stepper Motor
As we have discussed earlier that the stepper motor takes a much larger ampere than other types of motor, this makes the stepper motor less efficient and the vibration in the motor is also caused by the same issue.
Torque Drops Rapidly With Increase In Speed
As the motor speed increases, the torque of the stepper motor starts to decrease. Therefore, if you are looking for a motor that offers high torque at high speeds then choosing this motor may not be the right choice for you. You can use a servo motor instead.
Yes, you have read it clearly, if we compare the servo motor then the accuracy of the stepper motor is less but if we modify the stepper motor then the loss can be overcome. But again, the modification means that it will increase the cost of the motor and later the cost of the application.
No Feedback Used In Stepper Motor Indicates To Missed Steps
After reading this point you might be thinking that if not having feedback system is a disadvantage then why did I mention it in the advantages section? Your question is infallible and the question is answered below.
If the motor is operating with optimum weight on its shaft, the motor will perform perfectly.
But if the load is high, the motor will attempt to move quickly and this may cause the motor to skip the step.
And as there is no feedback path in the system to track this change, it will start the motor running slightly out of the adjustment made in its initial state.
On top of this, if we do not pay attention to this change, the application will start failing.
This is why not having a feedback system can affect the accuracy of the motor but this problem can be immersed using an external encoder.
So, in this blog, we have learned what is stepper motor and its advantages and disadvantages.
I hope you liked my presentation if there is any query, please let us know in the comments section. In my next blog, we will discuss the types of stepper motors.