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Stepper Motors vs. Servo Motors - Understand Your Robotics Needs

POSTED 07/19/2022

In the past we have seen the rise of stepper motors - small, compact motors that used low speeds at higher torque for a lower load capacity. Nowadays, servo motors run the industrial world, thanks to their high speeds, large load capacity, and better positional control.

Thus, picking between stepper vs. servo motors is as confusing as understanding their operation. The good thing is that we have got you covered as the following guide covers all about stepper motors vs. servo motors!

Stick around until the end to find more about how stepper and servo motors work, their benefits and cons, a grand comparison table, and a guide to choosing the right motor type according to your robotic needs! In the end, we'll also include some common FAQs to help you with your decision!

How do Stepper & Servo Motors work? The Quick Overview

The following is a quick overview of stepper and servo motors, including their advantages and disadvantages.

How Does A Stepper Motor Work?

The working of a stepper motor is carried out by an open loop system which, powered by alternating currents, causes the motor to "step" through a number of intervals. The resulting movement then creates a pre-programmed rotational motion and positioning.

The primary parts of a stepper motor are a rotor, magnet, and stator. Other parts include front and rear endcap, winding, ball bearing, and shaft.

The stator, acting on the rotor, creates a magnetic force that determines the rotational motion and static motor position. The permanent magnet also plays its role in turning the motor rotor in discrete intervals. This allows the motor to carry a load, a feature that makes them suitable for applications requiring good position and loading.

The best thing about a stepper motor is its simple design and easy operation. The motor also features a good low-speed torque which facilitates towing things from a standstill, as a greater horsepower generates with high torque.

Because the high torque at low-speed results in smooth motor working, the motor can get timely commands and its motion becomes synchronized accordingly. This feature makes stepper motors a better choice than servo motors in which incoming commands delay the motion.

However, when integrated into long movements, the same torque speed is a disadvantage in stepper motors. It limits the duty cycle and withholds the motor from reaching a peak torque value.

Yet, stepper motors have other features over servo motors, including quick responses when it starts. The low-speed torque results in a good low-speed workflow, and the function requires no prior tuning.

The compact size of the motor also makes it possible for the machine to save more energy, thanks to its simple, lightweight design. The motor's reduction of self-weight further impacts the overall cost, making stepper motors cost much less than servo motors.

However, because the motor runs in an open loop, the constant current flow sometimes becomes a problem when the operational requirements need a variable current voltage. The torque value also gets lower with the increase in speed, which limits the stepper motor's function to light loads only.

Pros & Cons of Stepper Motors

Let's look at the benefits and disadvantages of stepper motors.

Benefits

A stepper motor may be the best solution to your robotic needs due to the following benefits:

  • It has a simple design.
  • It has a lightweight body.
  • It is easy to control.
  • It starts quickly without any delays.
  • It uses low-speed torque that results in horsepower.
  • The low-speed torque contributes to a good low-speed workflow.
  • The motor's functioning requires no prior tuning.
  • The compact design of the motors helps save more power.
  • The lightweight body decreased the overall motor cost.
  • The motion of stepper motors gets synchronized with commands.
Cons

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