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

The air compressor pumps air into the storage tanks to maintain system pressure needed for braking.

Question 2

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

Accepted Answer

100–125 psi

Answer

The governor cuts out the compressor at around 100–125 psi to prevent over-pressurization of the system.

Question 3

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

Accepted Answer

80–85 psi

Answer

The governor cuts in at around 80–85 psi, signaling the compressor to resume pumping air.

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

The air dryer removes moisture and contaminants from compressed air to prevent water buildup and freezing in the system.

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

The air compressor is driven by the vehicle's engine through a belt or gear connection.

CDL Air Brake - Commercial Driver's License Air Brakes Test Practice Test