North Carolina CDL Air Brakes Practice Test

The air compressor governor is designed to monitor and regulate the air pressure in the braking system. It activates when the air pressure drops to a specific threshold, which is usually set between 85 and 100 PSI, depending on the vehicle. Once the pressure reaches this set point, the governor engages the air compressor to replenish the air supply and maintain optimal pressure for the braking system to function effectively. This regulation is crucial because inadequate air pressure can lead to braking system failure or impaired performance, posing significant safety risks. Therefore, the frequency of activation is not based on time intervals or specific actions like acceleration or brake application, but instead relies on the air pressure itself. The governor's automatic response to a predetermined pressure threshold ensures that the air brake system remains responsive and effective throughout its use.