How Brushed Motors Work and Why Motor Break-In is Important

A brushed DC motor is a type of electric motor widely used in various applications due to its simplicity and effectiveness. Here’s how it works:

Components of a Brushed Motor:

  1. Stator: The stationary part of the motor, often consisting of either permanent magnets or electromagnetic windings.
  2. Rotor (Armature): The rotating part of the motor, which includes windings.
  3. Brushes: Conductive carbon blocks that make sliding contact with the rotating commutator.
  4. Commutator: A rotary electrical switch on the armature shaft that periodically reverses the current direction.

Working Principle:

  1. Electric Current & Magnetic Field: When electric current flows through the armature windings, it generates a magnetic field. The stator also has a magnetic field (from permanent magnets or electromagnetic windings).
  2. Interaction of Magnetic Fields: The interaction between the magnetic field of the armature and the magnetic field of the stator creates a force. This force acts on the armature, causing it to rotate.
  3. Role of Commutator and Brushes: As the armature rotates, the brushes maintain electrical contact with the commutator. The commutator periodically reverses the direction of the current in the armature windings as it rotates. This reversal is crucial because it keeps the armature rotating in one direction. Without this, the armature would stop rotating after a half turn when the magnetic poles align with the stator’s poles.
  4. Torque Production: The continuous switching of the current direction, combined with the magnetic interactions, produces torque, which is the force that drives the motor’s rotation.


Brushed motors are used in various applications, including toys, tools, household appliances, and some types of industrial equipment. They are favored for their simplicity, ease of control, and low initial cost.


  • Wear & Maintenance: The brushes in these motors wear down over time and require maintenance or replacement.
  • Sparking: Brush contact can create sparks, which is a limitation in certain environments.
  • Efficiency: Brushed motors are generally less efficient than brushless motors, especially at higher speeds.

Despite these limitations, brushed motors remain popular for many applications where the benefits outweigh the drawbacks.

In this blog post, I’ve referenced the educational video titled “How does an Electric Motor work? (DC Motor)” which offers a detailed and accessible explanation of the workings of DC electric motors. You can watch this insightful video by following this link: How does an Electric Motor work? (DC Motor).

I extend my sincere gratitude to the creators of this video for their excellent and informative content. Their work has been instrumental in providing a clear and comprehensive understanding of the subject, which has greatly enriched the content of this post.

Why Motor Run-In is Important:

The process of running in a brushed motor, also known as breaking in or bedding in, is essential for several reasons:

  1. Brush Seating: New brushes may not perfectly match the curvature of the commutator. Running in the motor allows the brushes to wear slightly and conform to the commutator’s surface, ensuring better contact and efficiency.
  2. Minimizing Sparking: Proper seating of the brushes reduces sparking, which can cause damage and reduce the efficiency of the motor.
  3. Wear Reduction: Gradually breaking in the motor can reduce initial wear and tear on the brushes and commutator, extending the life of these components.
  4. Improved Performance: A well-run-in motor typically operates more smoothly and efficiently. This process ensures that the internal components mesh well and work as intended.
  5. Reducing Electrical Noise: Proper seating of brushes can reduce electrical noise, which is important in applications sensitive to electromagnetic interference.

Run-In Process:

The run-in process typically involves operating the motor under light load and at varying speeds for a certain duration. This helps the brushes to seat properly and can involve both mechanical and electrical techniques to ensure optimal performance and longevity of the motor.

In summary, the run-in process is crucial for ensuring the long-term efficiency and reliability of brushed motors, especially in precision applications where optimal performance and minimal wear are essential.

This blog post features insights and information inspired by a video titled “Brushed Motor Rebuild and Break In” hosted on YouTube. The video can be viewed directly through this link:

Special thanks to the creators of this video for their informative and engaging content. Their efforts in producing this video have significantly contributed to the topics discussed in this post.