New Jersey Air Brakes Practice Test

At what psi does the air compressor stop pumping air?

1. 150 psi

2. 100 psi

3. 125 psi

4. 175 psi

The correct answer is: 125 psi

The air compressor in a vehicle equipped with an air brake system typically stops pumping air when the system reaches a pressure of 125 psi. This is a standard setting used in many commercial vehicles to ensure safe and efficient operation of the air brake system. At this pressure, the air tank is sufficiently charged to maintain proper brake function but not excessively charged, which could lead to potential damage or failure of equipment. After reaching 125 psi, the compressor will automatically stop pumping to prevent over-pressurization, ensuring the longevity of the compressor and the air brake system as a whole. Thus, this operating pressure is designed to balance safety and performance in air brake systems.