Georgia Commercial Driver License Practice Test

When does the air compressor governor stop pumping air into the tank?

1. When it reaches 100 psi

2. When it reaches 125 psi

3. When it drops to 75 psi

4. At all times

The correct answer is: When it reaches 125 psi

The air compressor governor is a critical component in the braking system of commercial vehicles, as it regulates air pressure in the air tank to ensure efficient brake operation. The governor typically stops the compressor from pumping air into the tank when the air pressure reaches approximately 125 psi. This pressure setting is designed to prevent over-pressurization of the system, ensuring that the air tank operates within safe limits. When the pressure falls below a certain threshold, such as around 100 psi, the governor will allow the compressor to start again to recharge the air tanks. This cycle of compressing air to a set maximum and then stopping helps maintain a consistent level of air pressure needed for braking and other pneumatic systems in the vehicle. Thus, the 125 psi mark is essential for maintaining the proper function and safety of the air brake system.