Understanding How Carbon Brushes Work In DC Motors

Some favour DC motors in the industrial field for its low-cost, functions and many applications. However, knowing how they operate and completely understanding the equipment from start to bottom is another matter.

Regardless of whether it is a DC motor or any other equipment, it is always good to know how they really operate if you own one. Especially when it comes to failure, such knowledge will come in handy and help you to either maintain your equipment, solve the problem or improve it.

Now that you understand the importance, let’s walk you through the basics of carbon brushes in DC motors.

The purpose of carbon brushes in DC motors

The carbon brush is a critical component of a dc motor for many reasons. For a start, it transmits an electrical current which comes from the equipment’s rotating component to the centre. Also, during the rotation process – it is responsible for alternating the course of current in the conductors.

Additionally, it makes sure the commutation of the current’s direction a couple of times per rotation of the equipment and acts as a good conductor.

Besides these functions, it also keeps the surface of the commutator, or slip-ring, clean.

The material of the brush – carbon – also plays a huge role. It comprises all the physical, mechanical and electrical properties needed for protecting the equipment from damages. It’s self-lubricating properties also results in lesser wear and tear on the commutator as compared to brushes which are made from tougher metals like steel or copper – letting it achieve its optimal condition and smoothness.

Common faults

Just like any other part of your motor, it is bound to meet failure in time to come. Likewise, it means that there are certain signs to look out for before you decide to go for an electric motor repair in Singapore. The following are some of the possibilities:

  • Reoccurring problems with the commutator (E.g. Worn brushes which are causing excessive sparking)
  • Damaged brushes due to electrical overloading or unloading
  • Incorrectly installed brushes or wrong sized brushes being put in place
  • Wrongly shaped brushes which are unable to fit the arc of the commutator
  • Severe voltage surges

The consequences of worn carbon brushes

Although carbon is indeed the most efficient among other materials when it comes to brushes – it is bound to wear out eventually.

It is a soft metal which its purpose is to lessen the amount of damage caused to the commutator due to friction. So, when a carbon brush starts to spark – you’ll know that it is starting to wear out.

Once it reaches the point where its completely worn out, the motor’s performance will be affected and it will begin to underperform before meeting failure. Moreover, if the carbon brushes are not repaired or replaced – it may result in severe damage to the motor – causing it to break down and lose the ability to operate permanently.

In cases like these, you might have to enlist the help of an experienced engineer to do electric motor overhauling for a thorough check on the equipment’s condition. If it’s a faulty carbon brush – then you’ll know that it’s time to take action and resolve this matter.

Maintaining and extending the life of carbon brushes

Despite being susceptible to wear and tear, carbon brushes are still pretty reliable. With proper usage, care and maintenance, you will be able to extend their lifespan easily. Similarly, brushes in better condition lead to enhanced performance and more efficient DC motor.

Here are some ways you can both maintain and lengthen the life of your carbon brushes in your DC motor:

Carbon brush stability

Look at the clearance in between the brush and brush holders to make sure it is stable and slides correctly. Also, take note of the distance between the commutator slip-ring and brush holder to make sure the brush holder is in the right position and angle.

Regular motor cleaning

Whether it is spotting copper dust or signs of commutator wear – you always have to keep a lookout so you can get rid of these issues immediately.

For instance, the presence of dust causes machine pollution, brush side gulling, high brush wear and grooving of commutators/slip rings. Usually, the best way to deal with these situations is to do regular maintenance or cleaning – it will make sure air filters give out clean air to the motor.

Chamfer the edges

By cutting away at the brushes, you are further ensuring that the carbon brushes do not wear out – just like how it is for commutators. Do what you can to correct any abnormality at the surface to avoid any brush damages while at the same time – extending its lifespan.

Get anti-dust grooves

It is best that you ensure the faces of the brushes comprise of anti-dust grooves. They are highly efficient in enhancing their optimal condition and performance. With the right length being used, the brushes are able to adapt to the continuous amount of pressure.

When your motor is experiencing failure, you might wonder about the causes. And usually, it may lie in a certain component specifically – for instance – a carbon brush.

So, take the time to learn the different parts of the motor – starting with a carbon brush. Electric motor rewinds may be effective in dealing with the problem but it’s always good to fully understand its uses and signs of failure, you will know if it’s time to call up an engineer and take action.

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