<p>The present invention relates to a brush 10 suitable for coming into contact with conducting plates 12 provided on an electric motor commutator 11. According to the invention, the brush has a means 15 for adjusting its pole coverage between the start of life of the motor and its stabilized operation. This is therefore a brush with pole coverage that can be varied over its operating life. Such a brush is more particularly fitted into a motor for a ventilation (air conditioning) system for motor vehicle.</p>