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27 Cards in this Set
- Front
- Back
When an air brake compressor piston is on its compression stroke, the inlet valve |
Is closed and the discharge valve is open |
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When the compressor is in it’s unloaded cycle |
The inlet valves are held open |
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The governor controls maximum air system pressure by |
Putting the compressor in the loaded cycle |
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The automatic drain valve drains moisture and contamination from the reservoir |
Any drop in reservoir pressure |
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Air brake antifreeze is used in the air brake system to |
Prevent moisture in the system from freezing |
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Desiccant type air dryers rely on |
Beads that absorb moisture vapour from the air stream |
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Single check valves are installed in the inlet line both the primary and the secondary service reservoirs brocade they |
Prevent air loss in the event of a failure in the other reservoirs |
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The function of the safety valve is to |
Limit air pressure buildup in the event of a governor failure |
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CMVSS 121 states the minimum pressure at which the low pressure warning devices must warn the operator is |
60psi |
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Nylon air brake tubing should not be used where it may be exposed to |
High temperatures Abrasion and wear Excessive movement |
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In the released position, the inlet/exhaust valves of the dual-circuit brake valve are in the following condition |
Inlets are closed and the exhausts are open |
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The dual-circuit brake valve holds its inlet and exhaust valves closed |
When the valve is in its balanced position |
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The function of the relay valve in the primary brake circuit is to speed up the |
Application and release of the primary service brakes |
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When the dual-circuit brake valve delivers 20psi of primary service application pressure, a relay valve with a cracking pressure of 2.5psi reacts by sending |
17.5psi to the primary brake chambers |
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A type 24 brake chamber has a |
Area of 24in squared |
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During normal brake applications, the secondary piston of the dual-circuit brake valve is applied by |
Primary service air pressure |
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The function of the quick release valve in the secondary brake circuit is to |
Speed up the release of the secondary service brake |
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What is the purpose of the primary circuit |
To allow the operator to control the application and release of the drive axle brakes |
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3 components of the primary circuit |
Dual circuit brake valve Service relay valve Drive axle brake chambers ABS modulators Primary reservoir Limes and hoses |
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What circuit is closest to the pedal assembly |
Primary circuit |
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What controls the secondary piston during a normal stop |
Primary air through the orifice |
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Relay valve |
Quick application and release of the service brakes |
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Cracking pressure |
The amount of air to get the piston to move downward and open up the inlet in a relay |
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Function of a service brake chamber |
Converts compressed air to mechanical force |
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Secondary circuit |
To allow the operator to control the application and release of the steer axle brakes |
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3 components of the secondary circuit |
Duel circuit brake valve Quick release valve Front service chamber Lines and hoses ABS modulators |
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Quick release valve |
Quick release of air from the service chamber |