When there is a need for cleaning the contact surfaces of commutators and slip rings with brushes, emery cloth with aluminum oxide is NOT recommended, as conductive abrasive particles will cause arcing and damage to the surface. Many times, stone cleaning, garnet paper and machining are not a convenient, sufficient, or cost-effective option for machines as the priority is to keep the downtime to a minimum. This is when the carbon brush can be designed to clean up the contact surface.

Cuando sea necesario limpiar las superficies de contacto de los colectores y anillos rozantes, NO se recomienda usar tela de esmeril con óxido de aluminio, ya que las partículas abrasivas conductoras pueden causar arcos eléctricos y dañar la superficie. Muchas veces, la limpieza con piedra, el papel granate (Garnett) y el mecanizado no son una opción conveniente, suficiente ni rentable para las máquinas, ya que la prioridad es minimizar el tiempo de parada. En este caso, la escobilla de carbón se puede diseñar para limpiar la superficie de contacto.

When working with DC machines, it’s not uncommon to find a customer who runs different products requiring a range of armature current. Unlike other conductors, where lower current is a good thing, carbon brushes are designed for a narrow range of current density. A unique aspect of carbon brush life is that brushes operating at a much lower current density than they are designed for do not last nearly as long as expected.

General guidance for performing brush seating or comutator reprofiling in the field.

Orientación general para realizar el ajuste del asiento de las escobillas o del conmutador en el campo.

Ever run across brush arcing or vexing commutation issues? This paper, presented at the 2013 EASA Convention, provides a approach to analyzing brush and commutation problems and failures.

There are times when a DC motor or generator experiences a catastrophic failure and the customer wants to know why it happened. One type of failure that seems to stimulate lively conversation is when the failure involves dramatic damage to the brushholders and commutator. The term "flashover" describes the appearance of the failure; the very name conveys an accurate mental image of the failure. The questions that arise next are predictable: "What caused this?" and "What can be done to prevent a recurrence?" Or, if the motor was recently repaired: "What did you do to my motor to cause this?!" The purpose of this article is to help you answer those questions.

When servicing DC motors, one of the many tests we do to determine the condition of the commutator is to check it for loose bars. We check for loose bars by lightly tapping the face of the commutator with a very small hammer. Then we check for suspicious sounds and movement or vibration of the bars as they're struck. A loose bar will have a dull thud while tight bars will have more of a crisp "peck." You should not feel any movement of the bar with respect to adjacent bars. If the commutator is molded or riveted,it is not repairable and it should be replaced. However, V-ring commutators can be repaired.