DC motors are widely used in industry and in vehicles, particularly in variable speed and direction applications.  DC motors can operate at a wide range of speeds motor have a higher starting torque than AC motors.

3 low voltage motrs with carbon brushes

Low Volt DC Motors with Carbon Brushes

Unlike alternating current (AC) motors, direct current (DC) motors require a mechanism to switch polarity to produce motor rotation.  One of the oldest and simplest methods is via carbon brushes transferring current to the commutator of the armature.  Carbon brushes are a wearable part and must be regularly maintained to keep the motor functioning properly.  A good preventative maintenance plan for DC motors includes regularly scheduled inspections of the carbon brushes and related components.

Here are the steps on how to inspect DC motor carbon brushes:

  1. Disconnect the motor from power. Make sure that the motor is not connected to any power source before working on it.
  2. Remove the brush covers. If installed, the brush covers are typically located on opposite side of the drive end of the motor and will give you access to the carbon brushes and springs.
  3. Inspect the brushes. Look for signs of wear, such as cracks, chips, or unevenness. If the brushes are worn down to less than 25% of their original length, they need to be replaced. Ensure that the brush pigtails are in good condition and securely connected to the brush connector.  If the pigtails are heat discolored from high amperage, there is a high probability that your motor needs a full recondition or repair.
  4. Check the brush springs. The brush springs should be in good condition and should not be corroded. The springs should all have equal tension to provide a consistent circuit to the commutator. If the springs are damaged or worn, they need to be replaced.
  5. Clean the commutator. The commutator is the part of the motor that the brushes rub against. Use a cloth to remove any dirt or debris. If new brushes are installed, it is imperative to use a commutator stone to seat the new brushes and ensure the commutator surface is clean with a consistent surface.  Failure to properly seat brushes can lead to under performance and/or premature failure of the motor.
  6. Reinstall brush covers. Once you have inspected and cleaned or replaced the brushes, you can reinstall the brush covers and the motor, if it was removed.
  7. Reconnect the motor to power. Once the motor is reassembled, you can reconnect it to power.

Here are some additional tips for inspecting DC motor carbon brushes:

DC Motor Brushes on Commutator

View of DC Motor Carbon Brushes installed

  • Check the brushes regularly, especially if the motor is used frequently.
  • If the brushes are worn down, replace them immediately. Worn brushes can cause the motor to overheat and fail.
  • When replacing the brushes, make sure to use the correct size and type of brushes.
  • Clean the commutator regularly to prevent arcing and overheating.
  • If the commutator is damaged, it will need to be serviced or replaced.

By following these tips, you can help to keep your DC motor running smoothly and efficiently.  To purchase replacement brushes and commutator cleaning stones, contact Genesis Electric Motors.