Educational Series – Brushed vs Brushless DC Motors
Brushed or Brushless?
There is often confusion regarding two of the most commonly used motors in motion control: brushed vs brushless DC motors.
A couple of the most frequent questions we see over and over are:
- Is one better than the other?
- Which one should you use for your project?
The answer to those questions are dependant on your project and budget.
Before deciding which type is best for you, you must first ask yourself a few other questions:
- Do you need something durable and reliable to last a long time?
- Will you have the time or ability to perform any required maintenance on the motor?
- Are you looking for something cheap to mess around with or test a prototype?
Despite confusion, the difference between brushed vs brushless DC motors is actually quite easy to understand. After reading this article, you will have a clear understanding of both types of motors and be able to make an informed decision when choosing the right motion control for your needs.
Before we compare the difference between brushed and brushless DC Motors, first, let’s understand the basics of a standard DC motor.
The DC (Direct Current) motor is built using nothing more than a spiral formed by an electric wire (coil) with a central, magnetic axis. When a current circulates through the spiral, a magnetic field is formed, attracting or repelling the poles of the magnets, spinning the central axis.
A DC Motor works when a current carrying conductor is placed in a magnetic field to produce torque. The torque causes the component to move. It’s what causes the “motoring action”. The interaction of the magnetic and electric fields creates an electromechanical force.
So now that we have an understanding of the standard structure of these two types of motors, we can determine the difference between brushed vs brushless DC motors.
Brushed DC Motors
Brushed DC motors use “brushes” (as the name implies) to mechanically control the direction of the voltage.
Take a look at the image above. As you can see, the carbon brushes form a contact between the rotor itself and the magnets. This is an important detail because it has the potential to cause an undesirable effect on your project. Because the parts in the brushed DC motor use physical contact to control the motion, this creates friction and noise, causing wear and decreased lifespan of the engine.
That said, the structure and control function in the brushed DC motor is very simple, which naturally makes it the cheaper option. Another benefit to this common type of motor, is that it has the advantage of delivering a greater torque than the brushless version.
Brushless DC Motors
The brushless DC motor is an electronically commuted motor. That means these types of motors are controlled electronically using electromagnetic energy. Therefore, this type of motor does not have brushes since it does not need them.
The brushless DC motor is made of two basic parts:
- the Rotor and
- the Stator
There is no point of contact between these two parts. As mentioned above, the brushless motor uses electromagnetic induction created by the current that circulates (flows) through its housing, surrounding the electric motor.
Another key difference between brushed vs brushless DC motors, is that, unlike the brushed version, the brushless motor uses a permanent magnet.
These types of engines require the use of an ESC (Electronic Speed Controller). This is used to control the flow of energy to the brushless motors, and thus, makes them the more expensive option when comparing brushed vs brushless DC motors.
The advantages of brushless DC motors include a long life span, little to no maintenance (since it’s not necessary to change brushes or clean the engine), and high efficiency as there is no contact and no loss for friction.
Disadvantages include the utilization of complicated motor speed controllers with this type of motor and a high initial cost.
Brushed vs Brushless DC Motors Comparison Chart
So now you understand the difference between brushed and brushless DC motors. You know the pros and cons of both types of motors. Pretty simple stuff right? Simple, yes, but critical information to know before starting a project.
Want to know more? Continue your motion control learning through our Education Series.
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