Electric motors are essential components in converting electrical energy to mechanical energy. However, while all motors perform the same function, choosing the right one is handy in delivering maximum torque. Thus, in this article, we’ll distinguish between the stepper motor vs. dc motor. Also, we’ll identify the critical properties of servo motors.
Stepper Motor
Fig 1: A Stepper Motor
Definition
Primarily, it’s a brushless DC motor that rotates in discrete steps.
Also, with computer-controlled stepping, it’s possible to realize extremely precise speed control and positioning. Hence, stepper motors are popular in precision motion control uses.
Component
It features multiple toothed electromagnets surrounding a central gear. This arrangement is handy in defining position. Also, a permanent magnet stepper motor uses direct current power. Nonetheless, it lacks the brushes and the mechanical commutator synonymous with DC motors. Hence, it’s a brushless DC motor.
Working Principle
The motor features a control system responsible for sending electrical pulses to a driver. Subsequently, the driver deciphers the impulses. In turn, it transmits a proportional voltage back to the motor.
Next, the motor will rotate in fixed angular increments. It is where it derives the name stepper motor. Also, note that an alternating current controls the coils’ polarity.
Advantages and Limitations
Advantages of the stepper motor include the following:
Fig 2: A Metal 3D Printer
- First, they are handy in facilitating precise positioning applications such as in X, Y plotters, and 3D printers.
- Also, they allow accurate control of the rotational speed.
- Thirdly, they feature low torque at low speeds.
- Lastly, they’re easy to control.
Their fundamental limitations include
- The motors have low efficiency. They will draw the most current when without a load.
- Besides, when the motor speed is high, their torque is significantly low compared to when running at low speeds.
- And most lack integral feedback on position. They are relatively noisy during use.
- Lastly, when running at high loads, they can skip some steps.
Applications
- 3D printers
- Medical imaging applications
- Security cameras
- Robotics
- CNC milling machines
Servo Motor
Fig 3: 3D Illustration of a Servo Motor
Definition
It belongs to the DC types of motors. Nonetheless, this synchronous motor doesn’t run continuously for an extended period.
Component
Primarily, this motor relies on a feedback system to sense the difference between the real and the desired speeds. Thus, the feedback facilitates adjustment of the output in correcting a drift from the desired position. It is handy in enhancing accurate positioning.
There are two types of servos, namely:
Continuous rotation motor servos
They can continuously rotate either in a clockwise or anticlockwise direction. Also, they can move at different ranges of speeds as guided by the command signal. Thus, they are useful for a wider range of applications than positional motors.
Positional rotation servos
They are handy in small-scale projects to achieve moderate precise positioning. Also, they rotate at a 180-degree angle and don’t aid in continuous rotation and speed control.
Working Principle
Fig 4: A Servo Motor
The interior motor design features a unique arrangement of the gears handy in mitigating the high speed of the internal motors. Simultaneously, there is a significant increase in torque output.
Hence, the servos gear design and rotation speed are imperative in generating high torque. Also noteworthy is that the servo features a microcontroller helpful in fixing the error signal. These control signals aid in moving the rotor to the final position.
Stepper motor vs. DC motor–Advantages and Limitations
Merits of servo motors
- They have high torque output when rotating at high speeds. Primarily, this is due to their closed-loop feedback control system, which is better than the stepper motor’s open-loop system.
- Also, they are available in a wide range of torque ratings and sizes
- Lastly, they are relatively cheap as some are plastic made, which also makes them lightweight.
Downsides of servo motors
- Positional motors have a rotation limitation. They can only rotate at an angle of 180 degrees.
- Also, they are synonymous with twitching during positional control. Primarily it’s because of the feedback mechanism that seeks to rectify any shift from the intended position.
Applications
- Elevator technology and robotics
- Telescopes and cameras
- Industrial control applications
Stepper motor vs. DC motor–DC Motors
Fig 5: Numerous DC Motors
Definition
They are devices with an electromagnetic coil and conductors whose interactions change electrical energy to mechanical energy. The two common DC motor types include brushless motors and brushed motors. Also, there are different DC motor sizes.
Component
Noteworthy, the name brushed is from the two stationary metallic brushes that provide winding current to the motor. The other major components include the static stator and the rotating armature
Stepper motor vs. DC motor–Working Principle
Fig 6: DC Motors
The stator gives the rotating magnetic field, which prompts the rotation of the armature. Also, a pair of magnets is handy in enveloping the electromagnetic coils via surrounding the coils. Thus, when the winding current in the wire passes across a magnetic field, it induces a force. In turn, this initiates the rotation of the coils.
Stepper motor vs. DC motor–Advantages & Limitations of Brushed DC Motors
Advantages
- They are easy to control as all one needs is the application of a voltage.
- Secondly, they deliver high toque output at relatively low speeds. Additionally, their mechanical power generation is high with an efficiency of approximately 75 to 80 %.
- They are relatively cheap and thus affordable.
Disadvantages
- They are prone to electromagnetic noise and physical noise during rotation.
- Also, the motors require regular maintenance as the tear and wear rate of the brushes is significantly high.
Applications
- Cordless drills
- Industrial applications
- Mobile phone vibrators
- Handheld fans
The Difference Between Stepper Motor vs. Servo Motor vs. DC Motor
Conclusion
In a nutshell, these three motors are suited to different functions as we have elaborated. Now you have all the key differences between the three types of motors. However, if there could be some further clarification you’d want to make, talk to us.
