The alternator brushes are in constant contact with the slip rings, so they experience friction due to alternator shaft rotation. It is only a question of time before the brushes become worn.

This Volvo D16 engine has a state-of-the-art pad-type mount for the alternator. It also has an automatic tensioner. The electrical system’s heart is the alternator, and understanding its ...

Assuming that the alternator has full output at an engine idle speed of 600RPM and the alternator belt drive ratio is 1:2, the alternator shaft runs at about 1200RPM. So for 12V applications, direct ...

For example, an alternator that has an SAE J56 rating of “150/300 13.5V” made 150 amps at 1,500-rpm alternator shaft speed and 300 amps at 6,000 rpm, at a test voltage of 13.5 volts.