At what pressure should the governor cut out in air systems?

The governor in an air brake system is a critical component that regulates the air pressure in the system to maintain proper operation. Typically, the cut-out pressure for the governor is set around 125 pounds per square inch (psi). This is the pressure at which the governor will stop the air compressor from pumping more air into the system.

Operating at this pressure ensures that the air brake system functions effectively without being overloaded, which could lead to potential safety issues or equipment failure. Consistently maintaining this cut-out pressure allows for optimal performance during brake application, ensuring that the air storage tanks are adequately filled for immediate use when braking is required.

The choice of 125 psi aligns with industry standards for air brake systems, providing a balance between adequate air supply and the prevention of excessive pressure build-up, which is essential for safety and performance in heavy vehicles like school buses.