In this post, we will know what is Carbon Brush, why do we use only carbon brush in the motor. Why only carbon brush is used in the motor?
What is a carbon brush?
Carbon brush works to supply current in the rotor inside any motor or generator. All motors have a stator and a rotor inside. The stator remains fixed in one place. Therefore it is easy to supply current in it. But the rotor is always rotating, so if we connect the wire to the rotor then that wire will break, so we use a carbon brush.
what are carbon brush and commutator uses?
The carbon brush touches the rotor. The carbon brush does not connect directly to the rotor. There is a commutator with the rotor. The commutator and carbon brush connect together. Due to the rubbing of the carbon brush with the commutator, the current is supplied inside the rotor.
How to define a carbon brush?
It is a brush made of carbon that is used to supply current in the rotor of any dc motor or generator.
Where is the carbon brush used?
Carbon brushes are used in many places. Such as it is used in ac motor, ac generator, and autotransformers. We can see it in our homes as well, in homes mixer, grinder. We have already told you the need for this, it is used to supply current inside the rotor.
Questions may come across your minds like
1.Why only carbon brush used in the motor?
2.Why does carbon only use brushes in the motor, why aluminum or copper is not used in it?
There are several reasons for the answer to this question.
1. Melting point of carbon is high- The first reason for using a carbon brush is that the melting point of carbon is high. The melting point of copper is much lower than a carbon brush. The melting point of copper is 1050 ° C. This means that if the heat of 1050 ° C is given on copper, it will melt. But the melting point of carbon is 3500 degrees Celsius.
Carbon melting point and copper melting point
Here we need a material with a higher melting point because when the carbon brush supplies the electricity by rubbing it with the commutator. So at that time, there is a lot of temperature in between these two. Due to this, it is necessary to have material with a high melting point. If we use copper, it will melt. And if you use a carbon brush, it will not happen.
2. Carbon is soft as compare to copper- Carbon is much softer than copper. Its advantage is that when the carbon remains in touch with the commutator, there is friction in both. This causes damage to one of the two materials. If we use copper instead of carbon brush here, the commutator is greatly damaged due to the hardening characteristics of copper.
Working of carbon brush
If this is the carbon brush we use, then replacing the commutator causes more damage to the carbon brush. This is why we do not want to damage the commutator because the commutator is much more expensive than the carbon brush. The loss has to reach one of the two. But if the carbon damages the brush. So we can get a new carbon brush, it will cost us less. If this loss will be passed on to the commutator, then we will get the commutator at a higher price. So we use carbon instead of copper.
3. Negative temperature co-efficient of resistance- Carbon has a different property. When the temperature of the carbon is high, its resistance decreases. As we know that when there is friction in the carbon brush and commutator, the temperature increases significantly.
Why we use carbon brush only?
And here the special thing about carbon is that if the temperature is high then the resistance of the carbon brush will be reduced further. This gives us a lot of advantages because the resistance is less, then it is easy to flow. If the current is supplied easily then the rotor will not face any problem in running. Due to this property of carbon, we get a lot of benefits.
4. Carbon is self-lubricating- Whatever is carbon gets lubricated on its own. Lubricating means that we have to lubricate it by adding oil or grease to the barring inside our motor. But there is no need to lubricate carbon brushes. We need very low maintenance of carbon brushes.
Some other questions related to carbon brushes
Q1. Does only the carbon brush is used in the motor?
Ans. Yes, just carbon brushes, but the carbon brushes are used in a small motor. The larger size motor has a carbon graphite brush used along with carbon.
Q2. what is the price of a carbon brush?
Ans. The carbon brush used in the generator is available in the market for 25 to 35 rupees. We get a carbon brush used in the motor from 15 to 20 rupees in the market.
Q4. How long should carbon brushes last?
Ans. Carbon brush 1 year to 5-Lasts for 7 years. Due to rubbing with the commutator, it often worsens quickly.
Q5. what is the Weight of carbon brushes available in the market?
Ans. A fix is difficult to answer because the size and weight of the carbon brush vary according to the machine and the requirement, yet when we talk about the most commonly used small carbon brushes, they weigh between 10 and 30 grams.
So guys, hope you have got answers to many questions related to carbon brush used in motors and its importance.
Thank you
