Which of the following is an advantage of carbon brush over the copper brush

Which of the following is an advantage of carbon brush over the copper brush:

1. They are self lubricating in nature
2. Less damage in case of sparking
3. They are not hard as copper brush
4. All of these

Correct answer: 4. All of these

Explanation: All of the given options are advantages of carbon brushes over copper brushes. Here’s a breakdown:

1. Self-lubricating in nature: Carbon brushes have a natural lubricating effect during operation, reducing friction and wear on the contacting surfaces.
2. Less damage in case of sparking: Carbon brushes tend to produce less sparking compared to copper brushes, leading to reduced damage to the commutator or slip ring.
3. They are not as hard as copper brush: Carbon brushes are softer than copper brushes, contributing to lower wear on the commutator or slip ring.