CDL Air Brake Air Brake Compressor and Governor

Question 1

What is the primary function of the air compressor in an air brake system?

Accepted Answer

To pump air into the storage tanks

Answer

To release air from the brake chambers

Answer

To control the governor cut-out pressure

Answer

To pressurize the brake pedal

Question 2

At what pressure does the governor typically cut out the air compressor?

Accepted Answer

100–125 psi

Answer

60–80 psi

Answer

150–175 psi

Answer

200–225 psi

Question 3

At what pressure does the governor cut in and signal the compressor to resume pumping?

Accepted Answer

80–85 psi

Answer

20–40 psi

Answer

50–60 psi

Answer

100–110 psi

Question 4

What is the purpose of an air dryer in the air brake system?

Accepted Answer

To remove moisture and contaminants from the air supply

Answer

To cool compressed air

Answer

To increase system pressure

Answer

To store compressed air

Question 5

How is the air compressor typically driven on a commercial vehicle?

Accepted Answer

By the vehicle's engine via belt or gear

Answer

By an electric motor

Answer

By hydraulic pressure

Answer

By the transmission output shaft

Question 6

What can happen if the air compressor governor fails in the open position?

Accepted Answer

The compressor will run continuously and may over-pressurize the system

Answer

The compressor will stop working entirely

Answer

Air pressure will drop to zero

Answer

The brakes will lock up automatically