Industrial Machinery Repair Part Episode 1 Part 3 ppsx

10 Knowledge Area: Chain Drives 1 What is the maximum elongation that a roller chain can tolerate before it should be replaced?. Knowledge Area: Belt Drives1 Of the following, what are t

C Drip lubricator.

D Oil sump

18 A lubrication system in which the component needing lubrication rotatesthrough an enclosed housing containing oil and carries the oil to othercomponents is called a(n):

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

D All of the above

3 Thrust bearings:

A Support axial loads on rotating members

B Support radial loads on rotating members

C Will run hot if they are overlubricated

D All of the above

5 Bearing lubrication systems include:

A Lubrication by hand

B Central grease systems

C Pressure-feed oil systems

D All of the above

6 Plain bearings operate by:

A Separating the races with balls or rollers

B Using an air gap

C Hydraulics

D Running on a film of lubricant

7 Antifriction bearings operate by:

A Separating the races with balls or rollers

B Using an air gap

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 innerrace

C The allowed differences between bearing inner and outer race

D None of the above

10 Shaft tolerance can be defined as:

A The allowed difference between the shaft size and the bearing innerrace

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

C A hammer and punch

D None of the above

13 The bearing best suited for both radial and thrust loads is a

16 On a metric bearing with the number 7307, the ID of the bearing is:

D all of the above

20 A 20% increase in bearing load, can result in a % decrease inbearing 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

C 3%

D 3

16 inch per ft of chain

2 What causes roller fatigue?

A Lack of lubrication

B Contamination

C Improper chain tension

D All of the above

3 What problems will chain misalignment cause?

A Side plate wear

A Lubrication and alignment

B Lubrication and tension

C Tension and alignment

D All of the above

5 What type of machine guard limits the operator’s access to the dangerzone?

A Safety chain

B E-stop

C A barrier guard

D None of the above

6 What type of machine guard prevents access to the danger zonealtogether?

A An enclosure guard

B Safety chain

C Barrier guard

D None of the above

7 Name the two main groups of mechanical couplings:

A Rigid and flexible

B Chain and gear

C Grid and Lovejoy

D Spring and centrifugal

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 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

14 What causes roller fatigue?

A Lack of lubrication

B Contamination

C Improper chain tension

D All of the above

15 What problems will chain misalignment cause?

A Side plate wear

B Pin wear

C Chain break

D All of the above

16 What are the two most important factors in the life of a silent chain drive?

A Lubrication and alignment

B Lubrication and tension

C Tension and alignment

D Tension and speed

17 Name the two main groups of mechanical couplings

A Rigid and flexible

B Chain and gear

C Grid and Lovejoy

D Spring and centrifugal

18 What type of machine guard limits the operator’s access to the dangerzone?

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 zonealtogether?

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 12inch slack

C 5% slack between centers

D 2% slack between centers

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

D Both A and B

3 Which of the following is an acceptable V-belt installation process?

A Reduce center-to-center distance of the pulleys

B Use a pry bar to slide the belt over the pulleys

C Tension the belt until your hand bounces off the belt

D All of the above

4 Which of the following contribute to rapid belt wear?

A Oil, dirt, heat, and alignment

B Water, dirt, sunlight, and tension

C Guarding, shielding, reflection, and direction

D Sunlight, dry-rot, mold, and water

5 Why do timing or gear belts not require high tension?

A They do not require tensioning

B The material they are made of reduces slippage

C They provide slip-proof engagement

D There is not load fluctuation

6 Different speeds are required for various materials when cutting with aband saw How is saw speed adjusted?

A Set the speed indicator to the desired rpm and start the machine

B Adjust the belt tensioner and start the machine

C Start the machine and adjust the speed indicator

D Dial in the correct job selector and start the machine

7 Belt drives are designed to transmit power between a drive unit and a:

A Conveyor belt

B Motor

D Positive drive belt

9 A drive belt with the designation “C” would indicate which of thefollowing types?

A Power band belt

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

13 What criteria should be used to determine if a belt needs to be replaced?

A The belt protrudes above the top of the sheave no more than 1

16"

B The belt is flush with the top of the sheave groove

C The belt is recessed more than161 " into the groove sheave

D The belt is recessed more than1" into the groove sheave

14 The length of belt is determined by its:

A Pitch line

B V-line

C Standard line

D None of the above

15 When “timing” is a critical consideration with a belt, which of thefollowing is typically used?

A Joined belt

B V-belt

C Cogged belt

D Positive drive belt

16 Regarding sheave grove angle, which of the following statements iscorrect?

A Smaller diameter sheaves have less groove angle than larger ter grooves

B Larger diameter sheaves have less groove angle than smaller ter sheaves

diame-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

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

5 What function does a relief valve provide in a hydraulic system?

A Protects the system from overpressurization

B Dumps oil back to the tank

C Cools the oil

D A and B

6 What function does an actuator serve in a hydraulic system?

A To hold pressure in a system

B To assist the pump in flow

C To allow work to be performed

D A and B

7 What are the four basic types of center conditions (envelopes) in thedirectional control valves of a hydraulic system?

A Open, close, tandem, return

B Bidirectional, unidirectional, terminal, return

C Tandem, float, closed, open

D The center position is the same in all valves

8 What function do flow control valves serve in the hydraulic system?

A Control pressure to a point in the system

B Control the speed of an actuator

C Reduce the speed of a pump

D Eliminate return in one direction

9 What are the two basic types of flow control arrangements in a hydraulicsystem?

A Meter in, meter out

B Flow control, flow decontrol

C Meter in, direct flow

D Control, directional control

10 What are the two basic types of actuators in a hydraulic system?

D All of the above

12 The variable volume pump used most often in high-pressure systems iswhat 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 amedium 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 hydraulicsystem form a:

A Closed center system

B Bypass

C Circuit

D Motor

16 A needle valve in a hydraulic line provides a:

A Flow control orifice

B Pressure control orifice

C Relief valve

D Master valve

Knowledge Area: Couplings

1 A major advantage of flexible couplings is that they:

A Compensate for thermal expansion

B Provide greater torsional transfer than rigid couplings

C Require only minimal motor alignment

D Operate at higher rpm than rigid couplings

2 Name the two main groups of mechanical couplings:

A Rigid and flexible

B Chain and gear

C Grid and Lovejoy

D Spring and centrifugal

3 Which of the following couplings requires lubrication?

B Verify angular misalignment

C Verify parallel misalignment

D Check coupling spacing

6 Which of the following measuring tools is most useful for the edge method of coupling alignment?

straight-A Dial indicator

B Dial caliper

C Taper gauge

D Vernier dial indicator

7 Cooling tower fan shafts are supported by:

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?

A Proper gear mesh

B Unit operation beyond recommended capacity

C Gear wear

D Galling

12 High-speed gear-type coupling for motor-to-centrifugal compressor nections are typically lubricated by:

Benchmark your mechanical knowledge: Go to Appendix A for the correctanswers 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

95% –100% = Needs no training

As an industrial mechanic, you should always make safety your primaryconcern in the workplace No job should be performed that would endangeryour life or the lives of others Always remember, “Safety first, safety last,safety always.”

Each year in the United States more people are injured or killed in accidents

at home, at work, school, at play, or while traveling than were injured orkilled in either the Korean or Vietnam wars

Efforts to lessen or to eliminate the conditions that cause accidents areknown as safety measures Safety is a growing concern around the world,and safety skills are being taken more seriously today than ever before.People have come to realize that safety can be learned Safety expertsagree that it is possible to predict and prevent the majority of accidents.Few accidents simply “happen.”Most accidents are caused by ignorance, carelessness, neglect, or lack of skill.

Since the introduction of automatic devices to move and handle als, the exposure of workers to mechanical and handling hazards has beengreatly reduced; however, the basic principles of safeguarding continue to

materi-be of great importance Injuries result when loose clothing or hair is caught

in rotating mechanisms; when fingers and hands are crushed in rollers,meshing gear teeth, belts, and chain drives; and when moving parts sup-ply cutting, shearing, or crushing forces Machine guards are designed toprevent such injuries They may be fixed guards or automatic interlockingguards that prevent the operation of a machine unless a guard is in position

at the danger point Other types of guards prevent the operator from ing in contact with the dangerous part through a barrier, through devicesthat push the hands away, or through the use of sensor devices that stop themachine when hands are put into the danger zone

com-Making sure that the machinery, tools, and furniture associated with a job fitthe workers who do that job is known as ergonomics, or human engineer-ing A properly designed workplace can reduce worker fatigue and increasesafety on the job

Although many aspects of materials handling have been taken over bymachine, a great deal of manual lifting and carrying must still be done inindustry In such cases, it is important to avoid unsafe work practices, such

as improper lifting, carrying too heavy a load, or incorrect gripping Workersmust 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 decisionsbased on the known risk, are the best preventive management tools a main-tenance workforce can use The risk assessment will allow a company tomaximize its safety program and thus reduce accidents The risk assessmentprocess should be formalized in order to reduce accidents that could causeinjuries, death, machine damage, and longer equipment stoppage Onemust learn in maintenance that one must reduce risk at all times In anytask there are risk and thus the reduction or elimination of risk will makeall tasks more successful and safe

In order to perform a risk assessment one must know the risk and thenidentify countermeasures to reduce or eliminate risk Once one has reduced

or eliminated the risk, a maintenance person can then perform the task withknown acceptable risk The Risk Assessment Worksheet shown below willassist 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 isone of the important processes one must utilize in order to be successful.What makes this process so important is that lives are at risk if we do notfollow it

Note: The score noted on the far right has three numbers to score each riskafter countermeasures are in place Once the assessment is completed thenall scores are then added and matched to the Task Risk Scale at the bottom

of the chart