34 Maintenance Skills Assessment
C. Drip lubricator.
D. Oil sump.
18 A lubrication system in which the component needing lubrication rotates
through an enclosed housing containing oil and carries the oil to other
components is called a(n):
A. Dip lubricator.
B. Shot lubricator.
C. Drip lubricator.
D. Oil sump.
19 In a force-feed lubrication system, lubricant is moved to the component
needing lubrication by a:
A. Cooler.
B. Pump.
C. Filter.
D. Bearing.
20 What is the most undesirable by-product of oil misting?
A. Bearing failure
B. Shaft damage
C. Explosion potential
D. Oil breakdown
Knowledge Area: Bearings
1 The two basic categories of bearings are:
A. Plain and antifriction.
B. Ball and roller.
C. Journal and ball.
D. Pillow-block and roller.
2 Bearings:
A. Are found in machines with moving parts.
B. Function as guides.
C. Help reduce the friction between moving parts.

B. High-load applications
C. Wet environments
D. Mobile equipment engines
9 Bearing clearance can be described as:
A. The space between the rolling elements and the races.
B. The allowed difference between the shaft size and the bearing inner
race.
C. The allowed differences between bearing inner and outer race.
D. None of the above.
36 Maintenance Skills Assessment
10 Shaft tolerance can be defined as:
A. The allowed difference between the shaft size and the bearing inner
race.
B. The force applied during installation.
C. The space between the rolling elements and the races.
D. None of the above.
11 The preferred method for installing an antifriction bearing is:
A. With a sledge hammer.
B. To sand down the shaft until the bearing slides on.
C. With a bearing heater.
D. Both B and C.
12 When tightening the lock-nut on a spherical roller bearing, the preferred
tool is:
A. A spanner wrench.
B. A bearing heater.
C. A hammer and punch.
D. None of the above.
13 The bearing best suited for both radial and thrust loads is a
bearing.
A. tapered-sleeve

A. the shaft was too large.
B. of a lack of lubricant.
C. the operator failed to do the proper inspection.
D. of overlubrication.
19 An antifriction bearing can run hot because:
A. of overlubrication.
B. it is about to fail.
C. of excessive load.
D. all of the above.
20 A 20% increase in bearing load, can result in a
% decrease in
bearing life.
A. 20
B. 100
C. 50
D. 10
Knowledge Area: Chain Drives
1 What is the maximum elongation that a roller chain can tolerate before
it should be replaced?
A. 10%
B. 3 inches
38 Maintenance Skills Assessment
C. 3%
D.
3
16
inch per ft. of chain
2 What causes roller fatigue?
A. Lack of lubrication
B. Contamination

Maintenance Skills Assessment 39
8 Large fans are typically powered in what way?
A. Motor and belts
B. Motor and chain drive
C. Motor direct drive
D. Motor, gearbox, and belts
9 Which type of conductivity cells are usually equipped with a safety chain
to prevent the cell from blowing out?
A. Immersions
B. Insertion
C. Flow
D. Screw-in
10 Chain-linked fences should be topped with:
A. Three strands of electrically energized wire.
B. Barbed wire.
C. A skirt of the same material that kicks back 45 degrees and extends
18 inches.
D. None of the above.
11 What are the two links that make up a standard roller chain?
A. Roller, rigid
B. Roller, pin
C. Master, half
D. Offset, half
12 On a roller chain with a designation of 35, what do the 3 and the
5 designate?
A. 3 is the size in inches; 5 is the duty
B. 3 is the duty; 5 is the size in thousandths of an inch
C. 3 is the size in eighths of an inch; 5 means a rollerless chain
D. 3 is the size; 5 means heavy duty
13 What is the maximum elongation that a roller chain can tolerate before

zone?
A. Safety chain
B. E-stop
C. A barrier guard
D. None of the above
19 What type of machine guard prevents access to the danger zone
altogether?
A. An enclosure guard
B. Safety chain
C. Barrier guard
D. None of the above
20 What is the tension or slack a roller chain is recommended to have?
A. 10% slack between centers
B.
1
2
inch slack
C. 5% slack between centers
D. 2% slack between centers
Maintenance Skills Assessment 41
Knowledge Area: Belt Drives
1 Of the following, what are the four main types of belt drives?
A. V-belt; flat belt; timing belt; ribbed belt
B. Straight belt; V-belt; gear belt; ribbed belt
C. Rubber; vitron; buna-n; teflon
D. Round belt; dual face belt; V-belt; multibelt
2 Identify routine maintenance performed on flat belts.
A. Tensioning
B. Cleaning
C. Dressing

A. Cogged, fractional horsepower
B. Conventional V-belt
C. Narrow V-belt
D. Positive drive belt
9 A drive belt with the designation “C” would indicate which of the
following types?
A. Power band belt
B. Conventional V-belt
C. Narrow V-belt
D. Fractional horsepower
10 A drive belt with the designation “V” would indicate which of the
following types?
A. Positive drive belt
B. Conventional V-belt
C. Narrow V-belt
D. Fractional horsepower
11 A “C” belt with a nominal length of 60 inches is
4
10
" long. What
identification should be marked on the belt?
A. C410
B. C60/4
C. C64
D. C56
12 When replacing one of a set of belts, the mechanic should:
A. Replace the worn belt only.
B. Replace the worn belt and the belt closest to the drive motor.
C. Replace all of the belts.
D. Replace the worn belt and the belt farthest from the drive motor.

B. Larger diameter sheaves have less groove angle than smaller diame-
ter sheaves.
C. Groove angles are not affected by sheave diameter.
D. Can be compensated for by adjusting belt tension.
17 Which of the following conditions can cause excessive belt wear?
A. Dirty operating conditions
B. Improper sheave alignment
C. Improper tensioning
D. All of the above
Knowledge Area: Hydraulics
1 What function does a reservoir serve in a hydraulic system?
A. Stores surplus of oil
B. Cools the oil
C. Cleans the oil
D. A, B, and C
2 Why is there a baffle in a hydraulic reservoir?
A. To prevent baffling
B. To assist in cleaning and cooling of the oil
C. To keep the oil level the same
D. To prevent overpressurization of the reservoir
44 Maintenance Skills Assessment
3 What should the fluid pass through before it reaches the pump?
A. Prepump precipitator
B. Metal diffuser
C. Heat exchanger
D. Strainer
4 What are the three basic types of positive displacement pumps?
A. Centrifugal, gear, piston
B. Air pump, piston, centrifugal
C. Piston, gear, vane

B. Cylinder, motor
C. Double cylinder, single cylinder
D. Pump, actuator
11 Which of the following are means by which a directional control valve
may be actuated?
A. Manual
B. Solenoid operated
C. Pilot pressure
D. All of the above
12 The variable volume pump used most often in high-pressure systems is
what type of pump?
A. Vane
B. Piston
C. Gear
D. Centrifugal
13 Basic hydraulics theory tells us that pressure:
A. On a confined liquid is transmitted undiminished in every direction.
B. Acts with equal force on equal areas.
C. Acts at right angles only on the container side walls.
D. Acts with equal force on reduced areas.
14 Hydraulics is the science of transmitting force or motion through a
medium of a:
A. Confined liquid.
B. Nonconfined liquid.
C. A and B.
D. None of the above.
15 Component parts connected to each other by fluid lines in the hydraulic
system form a:
A. Closed center system.
B. Bypass.

5 When performing coupling alignment, the first activity that must be
conducted is to:
A. Check runout.
B. Verify angular misalignment.
C. Verify parallel misalignment.
D. Check coupling spacing.
Maintenance Skills Assessment 47
6 Which of the following measuring tools is most useful for the straight-
edge method of coupling alignment?
A. Dial indicator
B. Dial caliper
C. Taper gauge
D. Vernier dial indicator
7 Cooling tower fan shafts are supported by:
A. Hubs.
B. Bearings.
C. Couplings.
D. Back plate.
8 How are cooling tower fan blades attached?
A. Brazed
B. Welded
C. With U-bolts
D. Coupling
9 When a high-speed gear mesh coupling is removed from a compressor,
the coupling is typically match marked. What is the purpose of this?
A. Ensures that it can be reassembled correctly.
B. Ensures that it is disassembled correctly.
C. Ensures that one coupling half is aligned to mesh.
10 Some centrifugal compressors use a high-speed gear-type coupling. How
is this type of gear attached to the compressor shaft?

known as:
A. Impedance coupling.
B. Magnetic coupling.
C. Electrostatic coupling.
D. Dielectric coupling.
16 Which of the following comes in two pieces?
A. Coupling
B. Union
C. Bushing
D. Reducer
17 What type of fitting is used to connect tubing through a control panel
or junction box?
A. Coupling
B. Bulkhead
C. Compression
D. Cross
Maintenance Skills Assessment 49
Benchmark your mechanical knowledge: Go to Appendix A for the correct
answers and grade as follows:
Safety: total right/20 =
Lubrication: total right/20 =
Bearings: total right/20 =
Chain Drives: total right/20 =
Belt Drives: total right/17 =
Hydraulics: total right/16 =
Couplings: total right/17 =
Final Score: total of the scores/130 =
69% or below = Needs extensive mechanical training
70% –79% = Needs moderate mechanical training
80% –95% = Needs to review mechanical subject areas

Making sure that the machinery, tools, and furniture associated with a job fit
the workers who do that job is known as ergonomics, or human engineer-
ing. A properly designed workplace can reduce worker fatigue and increase
safety on the job.
Safety First, Safety Always 51
Although many aspects of materials handling have been taken over by
machine, a great deal of manual lifting and carrying must still be done in
industry. In such cases, it is important to avoid unsafe work practices, such
as improper lifting, carrying too heavy a load, or incorrect gripping. Workers
must take responsibility for their own safety.
The Risk: Performing a Risk Assessment
(the Preventive Management Tool)
The identification and the analysis of risk, and making rational decisions
based on the known risk, are the best preventive management tools a main-
tenance workforce can use. The risk assessment will allow a company to
maximize its safety program and thus reduce accidents. The risk assessment
process should be formalized in order to reduce accidents that could cause
injuries, death, machine damage, and longer equipment stoppage. One
must learn in maintenance that one must reduce risk at all times. In any
task there are risk and thus the reduction or elimination of risk will make
all tasks more successful and safe.
In order to perform a risk assessment one must know the risk and then
identify countermeasures to reduce or eliminate risk. Once one has reduced
or eliminated the risk, a maintenance person can then perform the task with
known acceptable risk. The Risk Assessment Worksheet shown below will
assist in the explanation of this process.
Risk Assessment Worksheet
The Risk Assessment Worksheet should be used for all maintenance tasks.
What is known in maintenance is that a maintenance organization, in order
to be successful, must have defined processes, and thus this worksheet is

and identified to lift
the direct lifting load
you are about to lift
(note lifting chains
must have identified
lifting capabilities
marked by the chain
manufacturer).
1
Lifting shackle does not
have center pin and
thus a grade 8 bolt will
be used
Death, injury,
equipment damage,
loss of equipment
run time
None needed. 3
One maintenance
person and one
unskilled person
changing the motor
Death, injury,
equipment damage,
loss of equipment
run time
Identify another
person skilled and
trained in rigging and
hoisting.

assessment process for all jobs planned. A copy of the Risk Assessment
Worksheet should be a part of the job plan package given to maintenance
technicians.
Lockout/Tagout/Tryout
All machinery or equipment capable of movement must be de-energized or
disengaged and blocked or locked out during cleaning, servicing, adjust-
ing, or setting up operations, whenever required. The locking out of
the control circuits in lieu of locking out main power disconnects is
prohibited.
All equipment control valve handles must be provided with a means for lock-
ing out. The lockoutprocedurerequires that stored energy (i.e., mechanical,
hydraulic, air) be released or blocked before equipment is locked out for
repairs.
Appropriate employees are provided with individually keyed personal safety
locks. Employees are required to keep personal control of their key(s) while
54 Safety First, Safety Always
they have safety locks in use. Employees must check the safety of the lockout
by attempting a startup after making sure no one is exposed.
Where the power disconnect does not also disconnect the electrical control
circuit, the appropriate electrical enclosures must be identified. The control
circuit can also be disconnected and locked out.
Manual Lifting Rules
Manual lifting and handling of material must be done by methods that
ensure the safety of both the employee and the material. It is important
that employees whose work assignments require heavy lifting be trained
and physically qualified by medical examination if necessary.
The following are rules for manual lifting: Inspect for sharp edges, slivers,
and wet or greasy spots. Wear gloves when lifting or handling objects with
sharp or splintered edges. These gloves must be free of oil, grease, or other
agents that may cause a poor grip.

ing program on safe methods of operation. All machinery and equipment
must be kept clean and properly maintained.
There must be sufficient clearance provided around and between machines
to allow for safe operations, setup, servicing, material handling, and waste
removal. All equipment and machinery should be securely placed, and
anchored when necessary, to prevent tipping or other movement that could
result in damage or personal injury.
Most machinery should be bolted to the floor to prevent falling during
an earthquake. Also, the electrical cord should be fixed to a breaker or
other shutoff device to stop power in case of machine movement. There
should be a power shutoff switch within reach of the operator’s position.
Electrical power to each machine must be capable of being locked out for
maintenance, repair, or security.
The noncurrent-carrying metal parts of electrically operated machines must
be bonded and grounded. Foot-operated switches should be guarded
and/or arranged to prevent accidental actuation by personnel or falling
objects.
All manually operated valves and switches controlling the operation of
equipment and machines must be clearly identified and readily accessible.
All EMERGENCY stop buttons should be colored RED. All the sheaves and
56 Safety First, Safety Always
belts that are within 7 feet of the floor or working level should be properly
guarded.
All moving chains and gears must be properly guarded. All splash guards
mounted on machines that use coolant must be positioned to prevent
coolant from splashing the employees. The machinery guards must be
secure and arranged so they do not present a hazard. All special hand tools
used for placing and removing material must protect the operator’s hands.
All revolving drums, barrels, and containers should be guarded by an enclo-
sure that is interlocked with the drive mechanisms, so that revolution cannot

majority of balancing problems using a vibration/balance analyzer, a porta-
ble device that detects the level of imbalance, misalignment, etc., in a
rotating part based on the measurement of vibration signals.
Sources of Vibration due to
Mechanical Imbalance
Two major sources of vibration due to mechanical imbalance in equipment
with rotating parts or rotors are: (1) assembly errors and (2) incorrect key
length guesses during balancing.
Assembly Errors
Even when parts are precision balanced to extremely close tolerances,
vibration due to mechanical imbalance can be much greater than neces-
sary due to assembly errors. Potential errors include relative placement of
each part’s center of rotation, location of the shaft relative to the bore, and
cocked rotors.
58 Rotor Balancing
Center of Rotation
Assembly errors are not simply the additive effects of tolerances, but also
include the relative placement of each part’s center of rotation. For exam-
ple, a “perfectly” balanced blower rotor can be assembled to a “perfectly”
balanced shaft, and yet the resultant imbalance can be high. This can happen
if the rotor is balanced on a balancing shaft that fits the rotor bore within
0.5 mils (0.5 thousandths of an inch) and then is mounted on a standard
cold-rolled steel shaft allowing a clearance of over 2 mils.
Shifting any rotor from the rotational center on which it was balanced to
the piece of machinery on which it is intended to operate can cause an
assembly imbalance four to five times greater than that resulting simply from
tolerances. For this reason, all rotors should be balanced on a shaft having
a diameter as nearly the same as the shaft on which they will be assembled.
For best results, balance the rotor on its own shaft rather than on a balancing
shaft. This may require some rotors to be balanced in an overhung position,