Brushes ordered from Ohio Carbon Inc. will be made from high-quality brush materials ranging from electro-graphite to heavy metal compositions. If the same grade is not available, a comparable grade will be used. If you feel that your current brush is unsatisfactory, our engineers will gladly recommend an appropriate grade for your application.
Electro-graphite is the most common of motor brush materials. The composition of carbon, graphite and appropriate binders provides for better commutation for industrial motors and generators than any other customarily used in motor brushes. Electro-graphite grades as a rule are harder, denser and have a longer brush life than the carbon-graphite series.
Carbon-graphite materials contain various proportions of carbon and graphite mixed with a binder, usually coal tar pitch, molded under pressure and baked or sintered. Graphite-carbon is a variant of this, used when graphite predominates the consumption. These materials are relatively strong and are higher in friction and abrasiveness then electro-graphite materials.
Graphite brushes contain graphite in a powdered form, which is mixed with a subtle binder and baked. Variations in processing make it a possible to offer graphite materials with a wide variety of properties. In general, graphite brushes have comparatively low resistance and friction and are used primarily on low-voltage motors, generators and on slip-rings.
Metal-graphite grades contain 75% or less metal, usually copper, which is mixed with graphite. They are manufactured similarly to graphite brushes with metal powders added to the graphite and binder. Metal-graphite brushes are used primarily on slip-rings and low-voltage generators and motors.
Metal grades are composed of more than 75% metal, principally copper or alloys of copper. They are used on some types of slip-rings and also in plating generators, annealers, continuous welding machines and other applications where a large amount of current must be transferred to moving parts.