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Small DC Motors: What It Is & Working Principle & Types

Small DC motors are used in many applications and have a unique working principle. These motors are quite famous for the multiple advantages they offer. If you are also looking to incorporate small DC motors in your applications and wish to know about them, then you will find this guide very useful.

In the guide below, we have compiled all the details associated with small DC motors, including their working principles, advantages, and how they can be implemented. So, let’s take a look and get to know some of the important information.


What is a Small DC Motor?

The first thing one must know is what a small DC motor is. Well, let’s learn this first, a small DC motor is such a device that converts electrical energy to a mechanical motion and hence is called an electromechanical device.

Benefits of Small DC Motors

There are many benefits of small DC motors when used with applications. Some of these benefits are as follows:

  • Small DC motors are very efficient, and they also help reduce the waste of energy and comprise a very low cost of operation.
  • The speed control is precise enough, and it helps adjust voltage, making it suitable for many applications.
  • Small DC motors reverse the polarity of the power supply, and hence the direction is changed.
  • Since these motors are very small in size, it is very easy to incorporate them into applications where weight is a major concern and offers flexibility in design.
  • The small DC motors are even known for their fast responses, so applications that need a quick start and stop cycle may find them ideal.
  • They are straightforward and have limited components, making them easier to maintain.
  • Small DC motors are widely available and very simple; hence they are cost-effective for most applications.
  • Small DC motors can be applied in many industries, like household appliances, electronics, medical devices, aviation, and automobiles.
  • In applications that need precise control of the speed and movements of the motors, these small DC motors are highly efficient.
  • They produce very low noise, and hence, in noise-sensitive applications, they prove to be a better choice.

DC Motors

Components of Small DC Motor

There are some important components of a small DC motor, and these are as follows:


The stationary part of the DC motor, which contains magnets in a circular pattern, is called the stator, and the magnetic field it possesses when it interacts with the rotator, a rotation is created.


The rotor is also called an armature, a part of the rotating DC motor. The armature comprises windings manufactured through copper wire and subjected to an iron core. The current flows through these windings, generating a magnetic field.


In a brushed small DC motor, some commutators are mounted on the rotor, and it has segments, whereas each is connected to the end of armature windings. When the rotor rotates, the brushes allow the motor to spin.

Electronic Circuitry

In the case of a small brushless DC motor, the commutation process is electronic; it doesn’t contain any commutators or brushes. The rotor instead has permanent magnets and numerous windings. The electronic sensors detect the position of the rotor, and the motor control maintains the rotation by switching the windings of the stator.


Types of Small DC Motors

There are many types of small DC motors, and some of the common types are as follows:

Permanent Magnet DC Motors

Permanent Magnet DC motors are small DC motors with permanent magnetic installed; these magnets help create a magnetic field for the stator.

In this motor, the windings armature is mounted on the rotor, and as soon as the current flows, it interacts with the magnetic field of the stator, causing the rotor to move in a circular direction. PMDCs are highly efficient and have a simple design; these are even quite cost-effective and can be used in small appliances and toys.

 DC Motors

Small Brushed DC Motors

Small bruised DC motors comprise brushes and commutators, which help reverse the direction of current in the windings and ensure a consistent rotation. The rotor, when spins, makes contact with the commutator and supplies the power to coils. Brushed DC motors are, however, less efficient and need more maintenance because of the wear and tear in brushes caused. They are used in fans, pumps, and other automated tasks.


Small Brushless DC Motors

Brushless DC motors are always very reliable and efficient because they do not have brushes that need constant maintenance. Also, they comprise a half-effect sensor that helps detect the rotor’s position. These are usually used in cooling fans, electric vehicles, and drones.


Coreless Small DC Motors

Coreless small DC motors are such kinds of brushed DC motors that have no iron core. In such motors, the windings of the armature are wrapped around a lightweight, supporting, and high-speed rotor. Since there is no iron core in these motors, the response of these motors is very quick and can be used for applications that need precise movements, like medical equipment, small robotics, and camera lenses.


Printed Armature DC Motors

Printed armature DC motors are such motors that have a PCB which works as an armature. The windings of this armature are directly printed on the PCB, and there is no need for traditional wire windings. These motors are lightweight and offer a great level of thermal properties. These are used in applications where weight and sizes are essential to consider, like aerospace.


Servo Motors

Servo motors are small DC motors ideal for precise control and positioning. These motors use the control systems to make sure that the needed position and speed are maintained. Such motors are very popular in CNC machines, robotics, and automation systems and are highly suitable for precision-based applications.

 DC Motors

Working Principle of Small DC Motor

Small DC motors work on the principle of electromagnetism; hence, when current flows through a wire in a magnetic field, the wire is subjected to a force that allows it to move.

In a DC motor, this principle works to create a rotational motion. Specific components of a DC motor consist of a stator that is a stationary component and comprises field magnets, the part that rotates is called the rotor.

The stator’s magnetic field interacts with the rotor, and it contains current, which causes the rotor to rotate upon interaction. To ensure the motor runs continuously, the current flowing through the rotor winding needs a reversal after every half of the rotation.

This reversal process is also known as commutation and by way of using brushes, it is achieved in brushed motors, and in brushless motors, electronic circuitry is used.


Characteristics of Small DC Motors

Small DC motors are equipped with specific characteristics which are essential for their applications, and these are discussed below:


Ratings for Voltage and Current

The voltage rating is the maximum voltage a motor can take without damage. Whereas the current rating ensures the maximum current that the windings in a motor can carry. The current and voltage ratings are essential when it comes to small DC motors because these are responsible for identifying motors’ power requirements and operating capabilities. These ratings need to match the application’s power supply to ensure that the operation is performed without causing any damage.


Power Consumption and Efficiency

The capability of a motor to convert electrical power into mechanical power is very important as it determines how efficient a motor is. The higher efficiency ensures that less power is wasted in the form of heat, leading to an efficient result with low power consumption.

These small DC motors are suitable for their energy efficiency in battery-powered applications.


Relationship between Torque and Speed

The relationship between torque and speed is an essential feature in a small DC motor. The load on the motor increases, the rotation speed decreases, and hence the torque also increases.

Similarly, when the load decreases, the speed of the motor increases, and the torque decreases. It is essential to consider the relationship between speed and torque when opting for this motor for applications to make sure that the desired demand for the application is met.


Factors to Consider When Choosing Small DC Motors

When choosing small DC motors, some of the essential factors that need to be considered are as follows:

Requirements of Application

When a small DC motor is chosen, the most important consideration is to make sure that the specific requirements of an application are taken into account. Every application needs different characteristics like torque, speed, duty cycle, etc. Hence, to choose the motor, you must analyze these factors for your application and make a relevant selection. Click here to know about where the DC motors it used often.


Weight and Size Limits

Small DC motors are widely used in applications where size and space are a limitation, and hence it is imperative to choose the small DC motor according to the device for which it is used. These small DC motors even have different sizes; hence, according to the weight and size requirements of the devices, the selection is made. In applications where mobility and portability are a concern, the size of the DC motors needs to be very small, for instance, in wearable devices.


Considering the Environment

The environment in which a motor will be operated is a significant concern; factors like humidity, dust, temperature, and exposure to chemicals and other liquids must be considered. The lifespan of the motor is highly dependent on these factors. Hence, applications subjected to such an environment must have a high IP rating based on small DC motors so that they can handle the environmental factors well.


Consideration for Cost

Cost consideration is always a significant decision when investing in a meter. The nature of your product and application will determine the cost of your motor. Depending on which type of small DC motor is needed for your application, you will analyze the cost of the motor.


How to Maintain a Small DC Motor?

To ensure that your small DC motor tends to perform with efficiency in the longer run, it is essential to maintain it, and some of the maintenance essentials are as follows:

Timely Cleaning and Lubrication

Every motor needs to be lubricated at specific intervals to attain optical performance. The motors attract dust and dirt, and by accumulating this debris, the motor would overheat and underperform. Hence, by cleaning it properly, the dust and debris is removed.

Moreover, the machine must also be lubricated; it helps reduce mechanical losses and maintains a smooth operation.


Replacement of Brushed

The small DC motors, which are brushed ones, wear out with time, and when this happens, it tends to impact the performance of the motor. Hence, it is imperative to replace the worn-out brushes and ensure that the machine is performing properly.


Ensuring Appropriate Ventilation

When the motor heats up during operation, the thermal management issues need to be fixed. This may require incorporating sinks and cooling fans. The airflow and ventilation around the motor must be managed well to prevent overheating.


Safety Precautions for Small DC Motors

Some of the essential safety precautions that need to be taken when making use of small DC motors are as follows:

  • It is essential to ensure that insulation, overcurrent protection, and grounding are all taken care of so that there is no chance of damage due to excessive flow of current, shocks, or short circuits.
  • The need to have protective guards during maintenance is also very important, and it helps avoid industries. Also, the motor must be balanced.
  • Heat dissipation strategies must also be utilized to ensure the motor doesn’t overheat, which could lead to motor failure. It is essential to ensure that the motor’s temperature is monitored.


Small DC motors are very popular nowadays because of their seamless benefits and ease of using and maintaining them. They have simple components and working principles, which you must have understood in the article above.

When implementing the small DC motors in any of the applications, you can always consider the points shared above and learn about these motors for more ease.

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