RevisionC-Developmentofconceptofcompressorforcommercialvehicle

drops to a range of 20 to 45 psi or 140 to 310 kPa (typically 20 to 30 psi or 140 to 210 kPa ). Do
not wait for the brakes to come on automatically. When the low air pressure warning light and
buzzer first come on, bring the vehicle to a safe stop right away while you can still control the
brakes. The braking power of spring brakes depends on the brakes being in adjustment. If the
brakes are not adjusted, neither the regular brakes nor the emergency/parking brakes will work
correctly. [6]
Figure 3:6: Spring Brake Actuator (component of air braking system)
3.3 Trailer control system
Trailer control system basically consists of the 4 components. This system uses the
compressed air from the compressor to perform its function.
3.3.1 Trailer air supply control
3.3.2 Trailer air tanks
3.3.3 Trailer control valve
3.3.1 Trailer air supply control
The trailer air supply control on newer vehicles is a red 8-sided knob which controls the
tractor protection valve. Pushing it in supplies the trailer with air, and pulling it out shuts the air
off and puts on the trailer emergency brakes. The valve will pop out and close the tractor
protection
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