Lavaelect ARS

Lavaelect ARS is Arc Resistant Sealant (ARS) was developed to provide a one-step, one material process to insulate the commutator end of armatures (the spider) used in D.C. traction motors. ARS has also been found to improve the life to failure by a factor of at least two times in actual field experience and by a factor of five times plus in laboratory comparison tests ASTM-D-2303-(inclined plane arc track test).
Prior to using ARS the armature’s commutator end was insulated with Mica or Nomex, which was bonded with layers of epoxy-saturated glass string banding. A teflon band is added over the string banding to prevent the build-up of carbon which would cause electrical shorts across the end of the commutator copper segments. Brush wear results in carbon dust deposits which tend to collect at the end of the commutator bars.