8th 6 Months Final Flashcards
To what type of energy does a hydraulic system convert electrical energy?
Usable
What is the function of a control valve in a hydraulic system?
All of the above
The hydraulic fluid in a system must be able to transmit power and
lubricate the system
Before working on a hydraulic system, the most important requirement is to
understand the system’s operation
If a hydraulic system is to function properly, it must
have all components installed correctly
Which of the following types of drawings illustrate the general location and appearance of a system’s elements?
Pictorial
What type of drawing illustrates the elements that make up a hydraulic system?
Schematic
On a schematic drawing, hydraulic components are represented by
symbols
The first thing to do when you read a schematic of a hydraulic system is to
obtain an overall view of the system
A schematic drawing of a hydraulic control valve illustrates fluid flow and
valve function
When installing hydraulic components, you should follow the installation techniques that
are required for each component
In order to provide proper alignments between a hydraulic pump and the driving motor, you should always
install the pump first
Which of these procedures should be followed when starting a newly installed pump?
Jog the drive motor
A stack of hydraulic control valves held together by bolts is called a
manifold
Which of the following statements about installing solenoid valves is NOT true?
Clip off the leads at the valve
Pump suction or inlet pipes should always be equal to or larger than the
pump intake
Which of the following must be considered when selecting hydraulic tubing?
All of the above
Which of the following should be avoided when assembling tubing?
Straight line connections
The disadvantage of using hydraulic hose in a hydraulic system is that it
wears out more quickly than tubing
Which of the following best describes most seals used in hydraulic components?
Preformed
What is the primary function of a hydraulic fluid?
Transmit force and energy
The lubricating capacity of a hydraulic fluid is dependent mostly upon its
viscosity
Which of the following items affects hydraulic fluid viscosity the most?
temperature
When you select a hydraulic fluid, always make sure it is
compatible with the system
Before filling a hydraulic system with hydraulic fluid, always make sure of the
system being clean
The interval of time between inspections on a specific hydraulic system depends on the
type of the system
Because inspections are made to locate trouble before a breakdown occurs, they are
preventive maintenance
After how many operating hours should the fluid in a hydraulic system be sent out for laboratory analysis?
1000
In many cases, repair maintenance can be scheduled for a later time. Under what conditions should this procedure NOT be followed?
When a safety hazard exists
When should hydraulic systems elements be reconditioned?
Periodically, and whenever they break down
Troubleshooting is best described as a means of determining trouble in a system by
means of a logical sequence
Prior to troubleshooting a hydraulic system, you should first evaluate the symptoms and then
determine the cause
The best way to protect a pressure gauge from surges is by
using a snubber with the gauge
When are fluid flow meters or gauges most commonly used in a hydraulic system?
During testing
Which of the following documents is the most helpful in solving a hydraulic system problem?
Maintenance record
The best way to determine if a valve is the cause of a system malfunction is to
test the circuit
Whenever a valve is disassembled for inspection or repair, you should always
replace the seals
Which of the following causes sludge formation?
Overheating of the hydraulic fluid
Which of the following could cause solenoid-coil burnout in a directional control valve?
All of the above
Which of the following tells how directional control valves should always be reassembled?
Carefully
Cylinder rod misalignment is usually caused by
side loading
A probable cause of an immovable or slow-moving cylinder may be
a blocked speed control valve
Which of the following hydraulic fluids is suitable for fire-resistant applications?
All of the above
Before connecting a cylinder to the hydraulic system, you should first
clean the piping system
Which of the following items is essential to proper cylinder performance?
Accurate mounting
Visual inspection of an operating hydraulic pump or motor is limited, because
You cannot see the internal parts
Broken pump rotors, fractured teeth or vanes, and repeated seal blowout are usually caused by
pressure shocks
Excessive wear and roughness in a gear pump are indications of
solid contaminants in the system
It is important to keep all contaminants out of piston pumps because of the pump’s
close-tolerance construction
It is good maintenance practice to replace which of the following when a hydraulic pump is repaired?
Anti-friction bearings, gaskets, and seals
What results when the volume of air in an air compressor is decreased?
Pressure increases
A dynamic air compressor is frequently referred to as a
non-positive displacement compressor
The size of a compressor air intake filter is determined by the
intake requirements
Corrosion-resistance piping is used in pneumatic systems to
extend pipe service life
After lubricating oil has been introduced into an air line, what is the recommended maximum distance that the air should travel?
30 ft
What kind o f drawings should be used to show the interconnections between components
Pictorial
What is generally illustrated in a schematic drawing?
Functions and operations
Pilot or signal lines are shown on a schematic drawing as
a series of long dashes
A schematic diagram can best be understood if the drawing is
studied in small segments
Special schematic symbols are usually devised and drawn by the
component manufacturer
In accordance with the American Society of Manufacturing Engineers’ code, air receivers must be equipped with safety valves and
pressure gauges
Slightly over-sized pipe
can help accommodate additional demands
What is the proper spacing for pipe supports or hangers?
Close enough to prevent sag
What should you do if an air leak occurs at a flared fitting?
Replace the flare
What is the proper length for hoses used to connect pneumatic components?
Only as long as necessary
A good planned maintenance program requires
regular equipment checks
A pneumatic system operated with excessive air pressure will usually have
accelerated wear
Most control valves in a pneumatic system are designed for use with pressure up to
150 psi
The best time to perform a daily check on compressor room equipment is
early in the shift
The operating cycles of control valves and cylinders used on production lines are usually entered in the
production record
Which of the following determines what troubleshooting checks to make in a pneumatic system?
The type and number of components
When you are troubleshooting a pneumatic system, first check the
supply air pressure
Which of the following would NOT be in the description section of an operations manual?
Troubleshooting procedures
Piston seals can be checked for leakage by
observing the exhaust port for air
Which of the following should you always inspect when troubleshooting a manually operated control valve for sluggish action?
Moving parts
Heat generated in the cylinder of a compressor during the compression stroke is best controlled by cooling the compressor and
limiting the compression pressure
An air compressor operating in a dusty or oily atmosphere should be cleaned at regular intervals with a
detergent
Which of the following causes the greatest discharge valve wear in a compressor?
Carbon deposits
A motor starting controller on a compressor is checked for proper operation by starting the compressor after the
reservoir pressure has been relieved
Which of the following is NOT a maintenance consideration common to all rotary compressors?
Intake valves
The best way of locating air control valve problems is to analyze the performance of the
circuit components
`Loss of power in a pneumatic control circuit can cause the circuit to
get out of sequence
What is used to activate a solenoid on a pneumatic control valve?
An electric current
A control valve that will shift manually, but not automatically, is likely to have
low air pressure
The use of an improper lubricant in a control valve may result in all of the following EXCEPT
shifting without a signal
What type of pneumatic cylinder is used for most industrial applications?
tie rod
The primary purpose of a piston rod bushing is to
act as a bearing
Above what temperature do pneumatic cylinders require special seals?
200 F
Improperly tightened or torqued tie rods on pneumatic cylinders will cause
internal misaligntment
What is the function of pneumatic cylinder cushions?
Prevent cylinder damage
The normal service life of air motors can be improved by
clean, filtered air
Which of the following is a proper lubricant to use when installing hose couplings?
Soapy solution
Air motors require careful handling during disassembly and assembly because they are
precision-built
Special attention should be given to the ____ of pneumatic grinders.
arbor shafts
Radial piston air motors require less maintenance that other air motors because they have
slower operating speeds
The low pressure in the hydraulic end of an air-oil tank system is overcome by the use of
large work cylinders
The main components of air-oil boosters are the
air pistons and hydraulic rams
What valve adjusts the makeup and return tank oil levels in a single-pressure booster system?
Manual shutoff valve
In a combined, single-unit air-oil cylinder, the fluids are separated by
a bleeder space
One advantage of interlocked independent air-oil systems is their
increased speed of operation
The best way to determine the correct running clearance in a plain-bearing installation is to
consult the manufacturer’s charts and tables
The ability of bearing material to dissipate excessive heat generated during operation is called
thermal conductivity
The ability of bearing material to flow slightly when loaded is called
conformability
An advantage of grease compared to oil in lubricating a plain bearing is that
newly applied grease forces old lubricants out
Discoloration in plain bearings is generally a symptom of
excessive heat
If you must leave your workplace temporarily, what care should you give a new, unmounted anti-friction bearing?
Wrap it in oil-resistant paper
To prevent creeping of an inner bearing ring around the shaft, you should mount the inner ring with an ___ fit.
interference
You can force an anti-friction bearing into position on the shaft by using an arbor press or by impact, if the bearing has an O.D. of
4 in. or less
A bearing is driven up a split tapered adapter by
tightening a heavy-duty locknut
A bearing running at a temperature above ___F usually indicates trouble.
200
What is the correct tool to use when removing a locknut from an anti-friction bearing installation?
A spanner
When you use a puller to remove a taper-mounted bearing, what should you do with the locknut?
Back the nut off several turns
An aluminum heating ring is designed for mounting and dismounting the inner rings of a
cylindrical roller bearing
When you use an aluminum heating ring to expand a bearing, heat the ring to
500 F
If you have cleaned and inspected an anti-friction bearing but do not intend to reuse it immediately, how should you treat it before wrapping it in oil-resistant paper and storing it?
Fill it with grease
Which type of bearing seal keeps out water, dirt, and contaminants most effectively?
Contact seal
Which type of anti-friction bearing can tolerate the most internal misalignment?
Spherical roller bearing
The correct tolerance range for shafts from 2 to 4 inches in diameter is nominal to
-0.001 in.
When you lubricate bearings with grease, the actual lubricant is ____, which is held in suspension
mineral oil
As a rule, the interval between lubrication renewals is cut in half for every 27 F increase in temperature above ___ F.
160
The threads of an acme screw are
squared off and thick
Ball bearing screws are designed to
move loads vertically and horizontally
The screw in a ball bearing screw is supported by
standard ball bearings
In a contact seal, what forms the actual seal?
A thin film of oil
Before you install a lip seal, you should chamfer the end of the shaft and the leading edge of the housing bore at an angle of ____ to ____ degrees.
15; 30
