It is very necessary to make sure that the carbon brushes stay in good contact with the commutator .
It is very necessary to make sure that the carbon brushes stay in good contact with the commutator .
确定一下碳刷与换向器是否保持良好的接触，是非常必要的。
It is very necessary to make sure that the carbon brushes stay in good contact with the commutator .
确定一下碳刷与换向器是否保持良好的接触，是非常必要的。