DC Motor, Servo or Stepper! How to select for your industrial automation equipment Project?
Which we should use for an equipment for an actuator of our equip? It is not a simple problem, because every engineer should face when they start a project, every automation equip need some actuator, all design is based the actuator. Some industry like Pneumatic air system, some like hydraulic system, for most of industry, people like use electric motors. In some small scale project, electric motor is your best option.
Normally there are three types of electric motors in markets. They are Stepper Motor, Servo motor, and Stepper Motor.
These are the simplest motors . DC Motor is also called continuous motors because shaft stops only when you switch off power source. Also if we change polarity its rotation direction also changes.
Servo motors are a combination of DC motor or AC motors with a feedback sensor system. Servo motors have a precise control over Speed whereas stepper motors on position.
Stepper Motors are electric motor and rotate in steps. These steps define by its coils arrangement. In stepper motor there are multiple coils which are organized in a group. When we supply power in a phase, it`s shaft will rotate one step. To use stepper motor we required some programmable device like Programming Logic Controller. But these motors have very good accuracy.
Selection of Electric Motor
Here in given table you can easily find the comparison of these 3 kinds of motors.
|Motor Comparison Chart|
|Features||DC Motors||Servo Motors||Steppe Motors|
|Controlled by Relay Switches||Yes||Yes||No，Required a controller|
|Speed Control||No,Required a gear box assembly||Yes,can be done by fb loop control||Yes,can be done in programming|
|Performance in load var ation||Good||Poor||Average|
|Preformance in cons回nt oad||Good||Best||Good|
|Breakingsystem on shaft||Notavailable||Notavailable||Ava ilab e|
|Availability in Market||Ea sly Available||Availablein selected stores||Available in se ected stores|
|Driver Circuit requlrment for one s de rotation||No||Yes||Yes|
The advantage of each motor:
It is very good for position control but it required a programmable device to operate. It is also expensive with respect to DC motor
It has very good for speed control and available in different standard sizes but required a special driving circuit.
It is easy to control but there is no speed control option. Well by gear box assembly you can control its speed.
But obviously it is not servo motor is your best choice, it is depend on your design and your purpose. Also with the development of technology, the dc motor or stepper motor disadvantage is less and less. Such as DC motor, you can use a gear box to implement speed control function. The stepper motor is more and higher in accurate position control.