Does a Car Generator Have Carbon Brushes?
2 Answers
Car generators do have carbon brushes. Below is relevant information about carbon brushes: 1. Definition: Carbon brushes, also known as electric brushes, serve as sliding contacts and are widely used in various electrical equipment. They function as devices that transfer energy or signals between the stationary and rotating parts of motors, generators, or other rotating machinery. The primary materials used in carbon brush applications include graphite, impregnated graphite, and metal graphite. 2. Function: Carbon brushes supply external current (excitation current) to the rotating rotor (input current). They also connect the main shaft (ground) to protection devices for rotor ground fault protection and measurement of positive/negative rotor-to-ground voltage.
Yes, car alternators do have carbon brushes, as I can tell you from years of repair experience. In older vehicles, such as certain vintage Toyotas or Citroëns, the carbon brushes inside the alternator are critical components. They transmit current to the rotor by contacting the rotating slip rings, helping to charge the car battery. However, carbon brushes are prone to wear and may fail after tens of thousands of kilometers, causing the alternator to stop generating electricity, dimming headlights, or preventing the engine from starting—prompt replacement is necessary. Modern new cars have switched to brushless alternators, which eliminate carbon brushes, reduce failures, and offer greater durability, saving hassle. However, some trucks or older models still use brushed types, so it's essential to inspect them during maintenance. Overall, technological advancements have made this issue less common, but don’t forget to check the alternator’s overall performance—otherwise, a dead battery will be even more troublesome.
