Technical Knowledge

Types and comparison of motors in motion control: servo, brushless, stepper
Release Date : 2020-08-28 16:39:38


Electric motors have been used in many applications. Before implementing motion control as a complex system, it is important to weigh the pros and cons of each type of motor, such as stepper motors, servo motors, and brushless motors. View the introduction of brushless motors, brush motors, servo motors, stepper motors, and reducers
 

Motor type

servo motor

 
The servo motor has a built-in encoder that serves as a feedback sensor. These sensors collect data about the position and speed of the rotor so that the servo motor can operate with high precision and consistency.
 

Brushed DC motor (single phase)

 
A brushed DC motor is a simple motor that relies on a magnetic field to move the rotor. Because the technology of brushed DC motors is not as complex as many similar motors, they can provide reliable performance at a relatively cheap price. However, the motor is subject to constant friction, which can cause wear over time.
 

Brushless DC motor (three-phase)

 
Developed from the brushed DC motor, the brushless DC motor is designed to operate in a more compact space, although it does not sacrifice performance. In a brushless motor, the current flows through the stator instead of the wire coil as in a brushed motor. Although brushless motors may be more expensive than their predecessors, they generally have a longer service life and require less maintenance.
 

Brushless AC motor

 
Similar to DC motors, brushless AC motors run current through the stator and have magnets in the rotor. The difference is that the AC motor runs with a constant current and rotates more smoothly. Brushless AC motors are very efficient. Therefore, they are very popular among motion control experts and professionals.
 

Other rotating motors

Stepper motor

 
The internal rotor of a stepper motor is affected by external magnets. After the winding generates energy, the teeth of the rotor rotate at a fixed pace. Because of the incremental movement of stepper motors, they can change speed and direction, so they are practical.
 

AC induction motor

 
AC induction motors are one of the most widely used motor types in industry and heavy machinery. The difference between the induction motor and the above-mentioned rotating motor is that the induction motor does not use permanent magnets. They rely on the rotating magnetic field generated in the stator to induce the rotation of the rotor.
 

Non-rotating motor

Linear Motor

 
As the name suggests, linear motors can be regarded as unfolding brushless motors. They are designed using the same basic magnetic theory, but they operate in an open form. One of the main advantages of using linear motors is speed.
 

Linear actuator

 
Linear actuators combine the technologies of rotating motors and linear motors to produce a cost-effective machine that has more functions than the above motors. However, there are trade-offs, and the actuator will reduce speed and compactness.
 

Compare

Stepper motor and small servo motor

 
Both stepper motors and small servo motors provide higher versatility. Servo motors have higher dynamic performance, and their torque can be up to three times that of stepper motors. But for those considering cost, stepper motors may be an effective option because of their lower cost.
 

Positioning of Servo Motor and Vector Motor

 
Both servo motors and vector motors can be useful in positioning applications according to system requirements. Since vector motors have great inertia, they are most suitable for heavy loads. On the contrary, the load handled by the servo motor is lighter, but the processing speed is faster.
 

Rotary motors (plus rotating to linear devices) and linear motors

 
When choosing between rotating or linear motors, be sure to clearly define your goals. Speed ??and accuracy should be two considerations, but cost may be the main factor. The upfront cost of linear motors will greatly increase.
 
What kind of motor is considering installing in your system? Learn more about each type of motor, and find the right motor through the "Product Center" catalog of NiMotion.