How to choose a suitable motor?



Most of the people do not know which motor is suitable for their mini projects, Final Year project and other projects. They just use try and error method to find out which motor is the most suitable for their project.Let‚Äôs figure it out on How to choose the suitable motor according to your project. ūüôā¬†

STEP 1: Why did you want to buy a motor?

  • A motor for a mobile robot?
  • A motor for a pulley?
  • A motor for a conveyor belt system?

STEP 2: Which motor that you want to use?

  • DC geared motor?
  • Servo motor?
  • Stepper motor?
  • Linear motor?
  • Power window motor?

Comparison of the motor:

DC geared motor Mobile robot, pulley, conveyor belt, lifting system. No Yes Rm40- Rm206
Servo¬†motor Control position Yes(0-180) No RM¬†26¬†–¬†Rm111
Stepper motor Rotation stage Yes (360) Yes Rm 26.50
Linear motor sliding door, No No Rm 349.80
Power window motor  Lifting, pulley, mobile robot. No Yes Rm 33.92

The price shown above is the price of the motor is sell by our company.

You can see more detail about our motor here.

STEP 3: What is the specification you need to know before you buy a motor?

  • Maximum Torque.
  • Maximum Weight.
  • Maximum Voltage.
  • Maximum Current.
  • Maximum Speed.
  • The diameter of the wheel use.

You can click here for more details  about our motor specification.

Just insert the value at input and then, you will get the specification of the motor you want at the output.

If you want to know how to calculate your motor specification by using mathematical formulas, please click here for more details.

The Example of the online calculator:


A good news for you: Here, I share a quick and easy method to help all of you to know the specification of your motor by using online calculator. Please click here.¬† ūüėÜ

STEP 4:  Where do you want to put your load?



STEP 5: Convert the torque given by the specification of motor to kg/cm.

Most of the motor specification on the market only show the torque, the current and voltage of motor not the weight that the motor can support. My suggestion, you need to convert the N.m to kg/cm with online converter calculator will be easier.

Question: What is the meaning of kg/cm?
Answer: We want to know the load in Kg the motor can support, for 1cm from the center of rotation.

Note: When the radius is increased, the weight can be supported will be lesser.

The picture below explaining about the meaning of the kg/cm related to motor.


Step 6: What that we need other than motor?

Writer - [Document 1 ] 21082015 85744 AM.bmp

Motor Driver

If you want to control the direction and speed of the motor.
Question: Why we need the motor driver?
Answer: Because the limited of power(current and voltage) from microcontroller.

Note: The motor driver is different from one another. So, you need to read the user manual of the motor driver carefully  before you buy and use it. You can see more detail about our motor driver here.



As a sensor, user is able to identify the speed of the rotation, angle of rotation, direction of rotation or even position of the shaft. It can be applied on a robot arm’s joint, mobile robot, conveyor system or even a printing machine.


Power Supply

Power supply is use to supply the current and voltage to the system. You need to choose your battery according to your motor driver. 

Note: You can click here for more details about our power supply.

STEP 7: Which motor driver suitable for your motor?

Most of student only knows about L293D as a chip to control the motor. The problem is, you need to construct the power supply and circuit. The current also limited if you use L293D.

The specification of the motor driver you need to check:

  • Maximum current support the motor.
  • The range of voltage to supply the motor.

¬†2 types of Cytron’s motor driver:

  • Motor driver
    Can control the direction and speed of the motor with the enough current.
  • Smart Drive Motor Driver
    Smart Drive Motor Driver is more easier to use, just plug and play to control the robot. You just need to choose your RC controller and then control your robot without microcontroller. It has the capability to accept RC (Radio Control) signal for mix mode drive, analog voltage from potentiometer, PWM from microcontroller, and even controlled via UART command. the operation modes is configure by the DIP switch. The commonly DIP switch configurations are printed at the back of PCB. MOSFETs are switching at 16KHz for quiet operation. With the on board temperature sensor, this smart driver is able to limit the output current stage by stage to prevent itself from overheat and burnt!

STEP 8: Choose the suitable encoder for your motor if necessary.

For your information, our company also sell a motor with the encoder together to make it easier for our customer to buy it. 

You can refer here  to see our product of motor with encoder and without encoder.

This tutorial just cover the basics element on how to choose your suitable motor. If you want to know more about the motor selection, there are so many explanations on the internet you can search and read.

If you have further inquiry about this tutorial, please post it in our technical forum here as we seldom check the comment section in tutorial site.

Thank You, I hope this Tutorial will help you to choose your motor.¬† ūüôā


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2 thoughts on “How to choose a suitable motor?

  1. Hello,

    I just wanna ask, how can I test the power window motor without opening the door of the car? Can it be tested on its own?

    Any reply would be much appreciated, thank you!

  2. You can directly connect the power window to 12V battery or power supply to test the power window motor.

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