“THE POOR CARBON BRUSH ALWAYS GETS THE BLAME”
“THE POOR CARBON BRUSH ALWAYS GETS THE BLAME”
but the carbon brush is not always the culprit. Here are some of the common machine ailments and their cures with hints on how to obtain longer brush life and better performance.
Here are some common scenarios that causes sparking in carbon brushes.
FAULTY COMMUTATING CONDITIONS, WHICH INCLUDE THE FOLLOWING
- Incorrect or unequal brush pressure
- Unequal brush spacing around commutator
- Faulty brush alignment (see note)
- Imperfect bedding of the brushes
- Commutating poles of incorrect strength
- Machine fault such as low IR
- Neutral point set incorrectly
- Machine overload or overspeed
- Unsuitable grade of brush
- Air gaps of unequal length because of wear of bearings
FAULTS IN ARMATURE
- Projecting mica on commutator
- Out of balance
- Bad joints in winding or equalisers
- Commutators flatted or otherwise out of true
- Loose commutator bars
BRUSH HOLDERS
- Brushes sticking in their boxes
- Brush clearance in boxes too great
- Holders set too far from commutator or brushes too long
- Incorrect brush holder alignment
MISCELLANEOUS
- Brush held off commutator by short or too stiff flexibles
- Loose connection in brush gear or field system.
- Vibration from external source.
- Chatter or brush
For expert advice on selecting the right carbon brush grade for your application, please contact us.