Millwright Exam Update 2024 Questions
and Correct Answers Rated A+
What are the 2 classes of hydraulics? -ANSWER-Hydrostatic &
Hydrodynamic
What causes pressure drop in a hydraulic line? -ANSWER-Excessive Fluid
Velocity
What causes aeration in a hydraulic pump? -ANSWER-Air in the suction
line
What type of hydraulic cylinder is indicated in the circuit in Figure 1? -
ANSWER-Adjustable cushion on extend only
What is Figure 2? -ANSWER-Pilot Operated check valve with a 5:1 line to
pilot pressure ratio
What valve is internally piloted from the outlet port and ext ernally drained? -
ANSWER-Pressure reducing valve
What valve discharges at a preset pressure? -ANSWER-Pressure Relief
Valve
What is the purpose of a pump? -ANSWER-Create Flow
Which valve limits system pressure when using a fixed displacement
pump? -ANSWER-Pressure Relief Valve
What is a symptom of a noisy pump? -ANSWER-Low fluid level in tank
Why can a pressure compensated variable displacement pump work
without a relief? -ANSWER-It shifts to minimum flow
,Where is the main purpose pressure relief valve located in a hydraulic
system? -ANSWER-Between Pump & control valve
What instruments are used for testing a hydraulic system? -ANSWER-
Tachometer, flowmeter & pressure guage
What are the brownish deposits found on valve spools? -ANSWER-varnish
what is the flare angle for hydraulic tubing that complies with JIC standards
-ANSWER-37" included angle
What diameter of hose is required for hydraulic hose fittings that has a
dash and number 12 on it? -ANSWER-3/4
What is a needle valve normally used for? -ANSWER-throttling
what is installed when high pneumatic cylinder speeds are required? -
ANSWER-quick exhaust valve
What does figure 3 represent? -ANSWER-Bidrectional, fixed capacity,
pneumatic motor
What does figure 4 represent? -ANSWER-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" -ANSWER-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 -ANSWER-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 -ANSWER-
3.192
,What is the average flow rate when an accumulator that holds 3 gallons of
usable oil discharges in 25 seconds? -ANSWER-7.2 gpm
What drives the female rotor on a screw compressor? -ANSWER-timing
gears
When over hauling a dry screw compressor how are the rotor clearance
specifications determined? -ANSWER-manufacturers manual
What determines the type of air filter used on an air compressor? -
ANSWER-duty or application
What are fins used for on a compressor discharge line? -ANSWER-cool
discharge air
what is done to control the output of the screw compressor? -ANSWER-
suction throttling
what is the purpose of a staple in a separator element gasket? -ANSWER-
prevent static electricity build up
What is the advantage of a three lobe blower over a two lobe blower? -
ANSWER-higher operating speeds
how are lobe to lobe clearance changed on lobe blowers? -ANSWER-
adjusting timing gears
how is unloading accomplished on electrically driven oil flooded vane
compressors? -ANSWER-throttling suction
what permits the flow from the separator to the vane compressor? -
ANSWER-oil return valve
what is the primary purpose of the minimum pressure valve on a wet sliding
compressor -ANSWER-maintain oil pressure
, What is the function of a servo valve on a vane compressor? -ANSWER-
controls the inlet unloader valve
What is the liquid in a liquid ring compressor? -ANSWER-water
what is the purpose of a separator in a liquid ring compressor system? -
ANSWER-separates the fluids from the discharge gas
how is the clearance set between the rotor and the cone on a liquid ring
compressor? -ANSWER-adjust rotor position axially
when are centrifugal compressors with barrel casing used? -ANSWER-high
pressure applications
which compressor converts velocity to pressure? -ANSWER-centrifugal
what is used to control dynamic compressor output? -ANSWER-inlet guide
vanes
why are adjustable stator blades used on axial compressors? -ANSWER-
adjust flow rate
what is flow reversal through a dynamic compressor called? -ANSWER-
surge
what is used to reduce thrust load on a dynamic compressor? -ANSWER-
balance piston
what has the same operating principle as a radial flow rate? -ANSWER-
centrifugal compressor
how is air pressure measured through a duct? -ANSWER-manometer
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