Millwright Exam Questions With Verified
Answers Graded A+
What are the 2 classes of hydraulics?
Hydrostatic & Hydrodynamic
What causes pressure drop in a hydraulic line?
Excessive Fluid Velocity
What causes aeration in a hydraulic pump?
Air in the suction line
What type of hydraulic cylinder is indicated in the circuit in Figure 1?
Adjustable cushion on extend only
What is Figure 2?
Pilot Operated check valve with a 5:1 line to pilot pressure ratio
What valve is internally piloted from the outlet port and externally drained?
Pressure reducing valve
What valve discharges at a preset pressure?
Pressure Relief Valve
What is the purpose of a pump?
Create Flow
Which valve limits system pressure when using a fixed displacement pump?
Pressure Relief Valve
What is a symptom of a noisy pump?
Low fluid level in tank
Why can a pressure compensated variable displacement pump work without a relief?
It shifts to minimum flow
Where is the main purpose pressure relief valve located in a hydraulic system?
Between Pump & control valve
What instruments are used for testing a hydraulic system?
Tachometer, flowmeter & pressure guage
What are the brownish deposits found on valve spools?
varnish
, what is the flare angle for hydraulic tubing that complies with JIC standards
37" included angle
What diameter of hose is required for hydraulic hose fittings that has a dash and number 12 on it?
3/4
What is a needle valve normally used for?
throttling
what is installed when high pneumatic cylinder speeds are required?
quick exhaust valve
What does figure 3 represent?
Bidrectional, fixed capacity, pneumatic motor
What does figure 4 represent?
Quick Exhaust valve
What is the area of the rod end of the piston when the cylinder has a diameter of 8" and the rod a
diameter of 2"
47.10 sq.in.
What is the maximum pressure a transmitter can produce when it has a 10" diameter low pressure
end and a 2" diameter high pressure end and system pressure relief valve is set to 1000 psi
25000 psi
What is the minimum diameter of a cylinder ram when a hydraulic jack exerts a force of 10 tons and
pressure guage reads 2500 psi
3.192
What is the average flow rate when an accumulator that holds 3 gallons of usable oil discharges in 25
seconds?
7.2 gpm
What drives the female rotor on a screw compressor?
timing gears
When over hauling a dry screw compressor how are the rotor clearance specifications determined?
manufacturers manual
What determines the type of air filter used on an air compressor?
duty or application
Answers Graded A+
What are the 2 classes of hydraulics?
Hydrostatic & Hydrodynamic
What causes pressure drop in a hydraulic line?
Excessive Fluid Velocity
What causes aeration in a hydraulic pump?
Air in the suction line
What type of hydraulic cylinder is indicated in the circuit in Figure 1?
Adjustable cushion on extend only
What is Figure 2?
Pilot Operated check valve with a 5:1 line to pilot pressure ratio
What valve is internally piloted from the outlet port and externally drained?
Pressure reducing valve
What valve discharges at a preset pressure?
Pressure Relief Valve
What is the purpose of a pump?
Create Flow
Which valve limits system pressure when using a fixed displacement pump?
Pressure Relief Valve
What is a symptom of a noisy pump?
Low fluid level in tank
Why can a pressure compensated variable displacement pump work without a relief?
It shifts to minimum flow
Where is the main purpose pressure relief valve located in a hydraulic system?
Between Pump & control valve
What instruments are used for testing a hydraulic system?
Tachometer, flowmeter & pressure guage
What are the brownish deposits found on valve spools?
varnish
, what is the flare angle for hydraulic tubing that complies with JIC standards
37" included angle
What diameter of hose is required for hydraulic hose fittings that has a dash and number 12 on it?
3/4
What is a needle valve normally used for?
throttling
what is installed when high pneumatic cylinder speeds are required?
quick exhaust valve
What does figure 3 represent?
Bidrectional, fixed capacity, pneumatic motor
What does figure 4 represent?
Quick Exhaust valve
What is the area of the rod end of the piston when the cylinder has a diameter of 8" and the rod a
diameter of 2"
47.10 sq.in.
What is the maximum pressure a transmitter can produce when it has a 10" diameter low pressure
end and a 2" diameter high pressure end and system pressure relief valve is set to 1000 psi
25000 psi
What is the minimum diameter of a cylinder ram when a hydraulic jack exerts a force of 10 tons and
pressure guage reads 2500 psi
3.192
What is the average flow rate when an accumulator that holds 3 gallons of usable oil discharges in 25
seconds?
7.2 gpm
What drives the female rotor on a screw compressor?
timing gears
When over hauling a dry screw compressor how are the rotor clearance specifications determined?
manufacturers manual
What determines the type of air filter used on an air compressor?
duty or application
