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How to Choose a DC Motor For Your Project

What is a DC Motor?

A DC motor is an electromechanical device that works to convert electrical energy into mechanical energy. In this motor, the current flows through a coil or windings that are placed within a magnetic field, which would result in the generation of rotational motion.

DC motor

Why Do You Need a DC Motor?

There are multiple reasons as to why you might need a DC motor. When choosing a DC motor, you need to know what project you would be working on. You could either want to use it for a conveyor belt system, a pulley, or even a mobile robot.

Based on the project you would be working on, there are different DC motors and technologies you can choose from that would be best suited for it.

What Are The Types of DC Motors Available?

There are various types of DC motors available, with the most popular being the brushed or brushless. Among these, we still have the servo motors, stepper motors, and vibrating motors.

1. Brushless DC Motors

hese are the types of DC motors that make use of permanent magnets in their rotor assembly. They are quite common because they can be used for most ground vehicle and aircraft applications.

They have higher power density than their brushed counterparts in addition to the fact that they generate less noise, require less maintenance, and are also more efficient. Some of their disadvantages include complexity, higher cost, and environmental limitations.

2. Brushed DC Motors

These are very simple DC motors and they can be found anywhere from automobiles, toys, and many other appliances. To alter the current direction, they utilize contact brushes that connect with a commutator.

The brushed DC motors have excellent torque at low speeds (which can be calculated in RPM or revolutions per minute) and are easy to control.

They are also inexpensive to produce. The downsides of this brushed DC motor is that it generates electromagnetic noise from brush arcing, it’s limited in speed because of brush heating, and also requires constant maintenance to replace the worn-out brushes.

click to read: Brushed dc motor vs brushless dc motor; Let’s break it down!

3. Servo Motors

Servo Motors

These are also another set of popular motors and their main use is for position control without precision. They are mostly used in remote control applications such as robotics and RC toy vehicles.

They are usually controlled through pulse width modulation (PWM) and they consist of a control circuit, potentiometer, and a motor. Servo motors can be DC or AC. DC servo motors are mostly used for small hobbyist applications.

click to read: The Difference Between AC Motor and DC Motor

4. Stepper Motors

These types of motors are more suitable for applications where precise positioning is needed. They can be found in process control systems, machine tools, and printers. The stepper motors are designed for high-holding torque to be able to offer the user the leverage to move from one step to the other.

While these types of motors are easy to make and control, they usually draw maximum current frequently. You can skip steps at high loads and small step distance limits top speed.

5. Vibrating Motors

These types of DC motors are normally applied in applications that need vibrations like game controllers or cell phones. They usually have an unbalanced mass on the drive shaft, which is the cause of the vibration and are also generated by an electric motor

Tips for Selecting a DC Motor for Any Application

It is a well-known fact that electric motors convert electrical energy into mechanical energy. But, when selecting a DC motor for your desired application, there are still certain factors you need to consider since there are a lot of motors available to choose from.

While the DC motor selection process can be quite a challenging one, we have some detailed tips to follow to make it more hassle-free. These tips include;

1. Define Your Duty Cycle 

When you are deciding what motor type will be great for your device or application, you need to first know your duty cycle. Some of the key aspects of your duty cycle include the directional rotation as well as dwell times and operating times. During the early phases of your DC motor selection, you should define your duty cycle.

If you are looking to extend the life of your DC motor, then you should opt for intermittent duty cycles. It can still be used continuously but having breaks between cycles can make for peak efficiency.

2. You Get More Torque With Gear Motors

There are times when you would require more torque for your application than you can get from a standard DC motor. At this point, you can opt for a DC gear motor as this will give you more torque but reduced speed, which is going to be based on the gear ratio that is utilized.

There are 3 types of gear motors, all of which have their advantages. These include worm gear motors, planetary gear motors, and spur gear motors. A gearhead can be added to brushed DC motors, brushless DC motors, as well as stepper motors.

3. Balance Size With Performance

Without a doubt, you need the proper motor size for your application, but there might be a problem if a specific performance is needed. Generally, smaller DC motors are not able to generate as much power as their larger counterparts.

So, based on the requirements of your desired application, you might need to cut down on some performance features to be able to accommodate certain size constraints.You can meet the size constraints for most applications by using various types of motors and technologies like motors with permanent magnets or brushless motors.

4. Measure Your Speed, Torque, And Voltage

The voltage, speed, and torque are the top specifications you need to consider for your DC motor application. Before selecting the perfect motor solution, these three specifications must be determined. You should make sure your motor is operating at maximum efficiency.

At the beginning of your motor selection process, ensure you define the motor voltage. The motor voltage will most likely be determined by the electrical power source in use, like a 12V battery or power supply. Typically, the nominal voltage for DC motors is either 12 or 24 VDC.

The torque is the amount of load the output shaft of the motor can overcome at one point in time. The motor speed and torque are linked to each other, in the sense that when one increases, the other decreases. The on-load torque, or rated torque, must be defined as it is with the speed.

What To Consider When Buying a DC Motor?

There are several factors to consider when you want to buy a DC motor, with velocity (RPM), torque, current, and voltage being the most important.

dc motor

1. Velocity

The velocity, also known as speed (RPM) determines how fast the motor runs. Generally, most motors run most effectively at the highest speeds, but that is not always the case if you require gearing. Always make sure you consider the speed and torque reduction.

2. Voltage

The voltage is important for keeping the net current flowing in a single direction in addition to helping overcome back current. If a DC motor has more voltage, it will automatically have higher torque. With a DC motor, ensure you apply the recommended voltage.

3. Current

What powers the DC motor is the current and too much of it could lead to damage. In DC motors, both the stall and operating current are essential. The stall current applies enough torque to allow the DC motor to run at stall speed, while the operating current is the average amount of current needed for the motor to draw under typical torque.

How to Choose a Replacement DC Motor

When you are looking to replace your DC motor, these are some of the things you should take note of;

1. Motor Nameplate Ratings

If you are not making any changes to the application, then you can get a new motor by simply matching the nameplate ratings of the old motor to the new one.

2. Motor Failure

If you need to change your DC motor due to a failure, then it is advisable to not go for the same motor as you could end up with that same issue. You can get a professional to help you find the cause of the failure by running some tests.

3. Location Requirements

If you want to replace your DC motor, make sure you consider the physical location requirements like the size of the motor concerning the available space.

You may also want to know: How to Choose a Coreless Brushless Motor: A Comprehensive Guide


So, depending on the type of project or application you are running, there are a lot of DC motors available for you to choose from. Also, ensure you keep in mind the essentials when choosing a DC motor for your project.

If you have anything else you need to know, you can click here to contact us at Donghui Motor, and we will have professional staff to answer your questions.


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