Motor Brushes for Electrical Machines, Tools and Automotive Vehicles
The first brushes for electric motors used copper strips of pressed copper gauze in order to transfer the current from moving conductors to stationary ones. Without being aware, we all use universal brushes for appliances and tools almost on a daily basis in regular household appliances or power tools i.e. vacuum cleaners, mixers or hand held drills. The last decade and till today more then ever, vehicle and auto brushes are used in the automotive & vehicle or auto industry.
Because of the poor properties of the early motor brushes, they were quickly replaced with carbon as the principal brush material. A large number of carbon grades for brushes has been developed, each for specific application. Brushes for starters, alternators and dynamos, etc. They can all be classified with different properties and for various applications.
The classes differ by their properties and applications, but each grade should fulfill two major conditions i.e. they must carry current without overheating or excessively wearing the parts against which they rub (slip ring or collector) with good commutation ability.