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MECHANICAL COUPLINGS &
ALIGNMENT
(MCA)
Learner Guide
TABLE OF CONTENTS
GENERAL INSTRUCTIONS PAGE 1
HOW TO USE THIS PACKAGE PAGE 2
PROGRAMME NO. 1 MCA-1
OBJECTIVE PAGE 3
TASK NO. 1: INSTRUCTIONS PAGE 4
RESOURCE NOTES PAGE 5
SELF TEST EXERCISE PAGE 12
TASK NO. 2: INSTRUCTIONS PAGE 14
RESOURCE NOTES PAGE 15
SELF TEST EXERCISE PAGE 17
PROGRAMME NO. 2 MCA-2
OBJECTIVE PAGE 19
TASK NO. 1: INSTRUCTIONS PAGE 20
RESOURCE NOTES PAGE 21
SELF TEST EXERCISE PAGE 23
CRITERION CHECK LIST PAGE 24
TASK NO. 2: INSTRUCTIONS PAGE 25
RESOURCE NOTES PAGE 26
SELF TEST EXERCISE PAGE 29
CRITERION CHECK LIST PAGE 30
TASK NO. 3: INSTRUCTIONS PAGE 31
RESOURCE NOTES PAGE 32
SELF TEST EXERCISE PAGE 34
CRITERION CHECK LIST PAGE 35
TASK NO. 4: INSTRUCTIONS PAGE 36
RESOURCE NOTES PAGE 37
SELF TEST EXERCISE PAGE 41
CRITERION CHECK LIST PAGE 42
PROGRAMME NO. 3 MCA-3
OBJECTIVE PAGE 43
TASK NO. 1: INSTRUCTIONS PAGE 44
RESOURCE NOTES PAGE 45
SELF TEST EXERCISE PAGE 47
CRITERION CHECK LIST PAGE 48
TASK NO. 2: INSTRUCTIONS PAGE 49
RESOURCE NOTES PAGE 50
SELF TEST EXERCISE PAGE 53
CRITERION CHECK LIST PAGE 54
TASK NO. 3: INSTRUCTIONS PAGE 55
RESOURCE NOTES PAGE 56
SELF TEST EXERCISE PAGE 61
CRITERION CHECK LIST PAGE 62
PROGRAMME NO. 4 MCA-4
OBJECTIVE PAGE 63
TASK NO. 1: INSTRUCTIONS PAGE 64
RESOURCE NOTES PAGE 65
SELF TEST EXERCISE PAGE 69
CRITERION CHECK LIST PAGE 70
CONTACT DETAILS:
https://techav.co.za
info@techav.co.za
Back to Table of Contents
1
MECHANICAL COUPLINGS & ALIGNMENT
(MCA.)
GENERAL INSTRUCTIONS
This series of programmes has been designed to afford you the opportunity to learn the
basics of a very important industrial subject, namely that of machine alignment.
The package consists of (4) programmes, each with its own video programme. Video
programmes describe and demonstrate important facts and procedures that the plant fitter
needs to know.
The workbook (this book) contains:
o Resource notes, which complement each video plus provide extra information.
o Exercises and self-evaluation tests.
The workbook is an integral part of your training and must be used in conjunction with the
video programmes and your instructor / supervisor or Course Controller.
It is strongly recommended that you begin with the FIRST programme (MCA-1) especially if
you have no knowledge of the subject.
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2
HOW TO USE THIS TRAINING PACKAGE
Please read this page carefully before continuing.
INSTRUCTIONS FOR LEARNING
Step (1) Read the objectives stated at the beginning of each task.
Step (2) Read the self test exercise which follows the resource notes.
N.B: If you can answer all the questions then you don't need instruction.
Ask your instructor to allow you to perform the CRITERION TEST for
the programmes in question.
Step (3) Read the resource notes for the programme you are involved in.
Step (4) View the video for the programme, following any verbal or on-screen
instructions.
N.B: You will see either "DISCUSSION" or "PRACTICAL" signs, accompanied
by music during the video programmes. At such times switch off the
video (i.e. STOP THE VIDEO) and check the instructions in the
workbook under TASK heading.
Step (5) At the conclusion of the video, stop the video.
Step (6) Perform the CRITERION TEST for the programme or, if you wish, perform
more practical exercises to gain experience and then perform the CRITERION
TEST.
N.B: Ask your instructor for the necessary criterion test instruction and
materials etc.
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3
PROGRAMME NO. 1 MCA-1
AN OVERVIEW OF MECHANICAL COUPLINGS
AND ALIGNMENT PRINCIPLES
OBJECTIVE
At the end of this programme you will be able to do the following:
o Identify commonly used linear couplings.
o Describe the basic principles and concepts of linear machinery alignment.
o Effect the necessary preparations for alignment.
AIM OF PROGRAMME
This programme has been designed to offer the newcomer (e.g. apprentice, learner
technician etc.) valuable basic information in the form of facts which should always be kept
in mind when performing an alignment job.
Knowledge and understanding of these facts will make the task of machine alignment more
interesting, meaningful and, most of all, save you or your company precious time and
money.
TURN THE PAGE FOR TASK NO. 1 INSTRUCTIONS.
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4
TASK NO. 1 - MCA-1
AN OVERVIEW
INSTRUCTIONS
o Read the resource notes beginning on the next page.
o Obtain the video MCA-1.
o Watch the video through to the end.
o Now play the video through to the first "DISCUSSION" break (you will see the word
"discussion" on screen and hear music).
o Stop the video at this point and attempt the first exercise in the workbook, following
the resource notes.
o Have your Instructor check your work.
o Proceed with the video viewing.
o Continue until you see the next "discussion" break and again perform the suggested
exercise or self test.
o Continue until end of video.
o Perform the Criterion Test which will be given to you by your Instructor or Course
Controller.
TURN PAGE FOR TASK NO. 1 - RESOURCE NOTES.
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5
RESOURCE NOTES
TASK NO. 1 MCA-1
AN OVERVIEW OF MECHANICAL COUPLINGS
AND ALIGNMENT PRINCIPLES
A mechanical coupling is a device employed to connect two shafts, end to end. The coupling
itself has to be capable of transmitting the rated torque capacity of the shaft and at the
same time accommodate any misalignment between the shafts.
Over the years, through trial and error and by design, many coupling types have been
developed. This overview attempts to describe some of the most popularly encountered
types, which can be loosely classified as:
(a) "Rigid Couplings" and
(b) The so-called "Flexible" couplings.
RIGID COUPLINGS
Although the simplest and cheapest form of coupling, rigid types demand "perfection" in
their alignment with the mating shafts. Any misalignment would result in undue forces and
rapid wear of bearings, casings and the coupling itself.
A simple form of rigid coupling is the "flange-faced" type (see Figure No. 1).
Fig. 1
Another form of solid coupling is the Ribbed type (see Figure No.2). In this type a key locks
the two shafts. Each shaft has a key-way machined at its end. The key is held by a two piece
coupler housing which is then bolted together in position.
Fig. 2
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6
FLEXIBLE COUPLINGS
So called because such couplings allow for an amount of misalignment, albeit only a very
small amount. Flexible couplings are by far the most commonly encountered and for
purposes of recognition we illustrate many types below.
Fig. 3 Gear Type Coupling
Fig. 4 Steel-Grid Type Coupling
("Bibby" Coupling)
Fig. 5 Flexible Disc Type Fig. 6 Flexible Link Type
Fig. 7 Roller-Chain Types
Fig. 8 Sliding Block Type
Fig. 9 Sliding Disc Type
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7
The "flexible-couplings" so far illustrated are normally steel constructed, however another
group of "flexible-couplings" utilise rubber, plastic or neoprene impregnated fibre or other
"soft" material to serve as a compressive cushion between the metal elements connecting
the shafts. Such couplings are described generally as "Elastomeric-Flex" couplings.
Common types of Elastomeric Couplings are illustrated hereunder.
Fig. 10 Compression Coupling
Fig. 11 Rubber Block
Coupling (Spider)
Fig. 12 Flexible Sleeve Coupling
Fig. 13 Shear Type Coupling
(Rubber Type)
So far we have illustrated some common types and designs of shaft or mechanical couplings.
There obviously are other types, styles and designs, but virtually all work on similar
principles. The need for so many types evolved from industrial demands for such
considerations as:
1. Cost.
2. Speeds and shafts.
3. Power transmitted.
4. Loads encountered.
5. Ease of maintenance.
6. Quiet operation.
… and other considerations.
For a more detailed explanation of couplings we suggest you study the various coupling
manufacturers' catalogues and service bulletins as it would be impossible to detail every
type in this programme.
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8
What is certainly important is that you understand the principles about connecting two
rotating machines together via their shafts. We generally refer to this feat as "alignment", so
let's spend some time in this subject, because much of your time spent on plant or
equipment maintenance will be spent on such tasks.
THE PRINCIPLES OF ALIGNMENT
As a general rule most plant operating equipment is run, or powered, by an electric or diesel
motor. For purposes of maintenance it is convenient to be able to separate the motor from
the equipment being driven. Several methods are used to "connect" a motor to a piece of
machinery (e.g. V-belts, roller-chains, gears or in-line couplings).
This programme deals only with "in-line" or "linear" couplings, whereby two shafts are
connected on their common axis.
In an ideal or perfect situation two units coupled together at their shafts would be
absolutely coincident, meaning that the two shafts would lie perfectly upon a common
centre, whether rotating or at rest.
This situation seldom occurs in practice. There are many reasons why; some obvious, others
less obvious. Draughtsmen and engineers strive for the "perfect-alignment" situation, but so
far it has been an impossible dream. Why is this? Well, for instance, as you know, a shaft is
supported by a pair of bearings. Bearings must have a certain amount of "clearance"
otherwise no rolling action could occur. As bearing clearances vary slightly, there will be a
certain amount of "free-play" either up and down (radial) or in and out (axial) at the shaft
end.
Further, machinery is usually mounted upon a concrete base, or at least the metal - plate is
secured into concrete. "Settling" of the base is commonly encountered whereby slight
movement causes one machine to move "off-line" with the other. We are not talking large
amounts, but a 1 mm movement of the bed plate can impose an angular deflection of shaft
centres of several degrees. Let's study these concepts in diagram form.
Fig. 14
Perfect alignment exists only when shaft centres are absolutely coincident, at rest and
rotating. Any deviation from the coincident centre line is considered as miss.-alignment.
Certain tolerances of miss-alignment are "allowed" and these are usually evident and
measured at the coupling area.
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9
For purposes of explanation we will grossly exaggerate miss-alignment angles in the
following diagrams. In essence there are two parameters of miss-alignment namely "axial"
sometimes called "angular" miss-alignment and "radial" sometimes called "parallel" miss-
alignment. In practice they often occur together so we have a combined axial and radial
problem to deal with.
Axial (or Angular) Miss-alignment:
Fig. 15 Side View (Exaggerated)
Fig. 16 Top View (Exaggerated)
Radial (or Parallel) Miss-alignment:
Fig. 17 Side View
Fig. 18 Top View
A popular miss-conception is that we align the "couplings" whenever a piece of machinery is
replaced. In fact we must align the "shafts", and the most convenient place to do this is at
the coupling. Most couplings consist of two "half-couplings". A half-coupling is the portion
that is attached or secured onto each shaft-end. If the half-coupling itself does not run
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10
"concentric" to the shaft then the combination will be miss-aligned no matter how well the
two half-couplings are "aligned". See diagram for visual explanation.
Fig. 19
Before any alignment correction is attempted, it is important that:
(a) The machine's shafts are checked for run-out.
(b) The half couplings run true to the shaft.
The above checks should be made using a dial-test-indicator (clock-gauge).
Fig. 20
NB: The necessary corrections should be effected prior to attempting to correct
alignment.
Ideally when two machines are brought together (Le. a motor and the driven unit) the two
half-couplings should be in alignment both axially and radially. It is seldom (if ever) that two
half-couplings actually contact each other during installation. A gap exists between the
couplings to either allow for thermal expansion (shaft growth) of the shafts or to
accommodate end floats. A specified gap is recommended by the design engineers which
must be adhered to.
Do not expect a "flexible-coupling" to compensate for fitting errors. The term "flexible"
implies that the coupling can "bend" or "twist", which of course it can. But the bending or
twisting action occurs owing to operating conditions, not by careless fitting. Flexible
couplings must still be carefully aligned according to set specifications.
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11
The results of careless or faulty alignment are:
o Rapid bearing failure.
o Machine vibration.
o Wear in the coupling itself.
o Shaft fatigue.
All of which result in costly breakdowns and of course much more sweat and toil for the
plant fitter!
SAFETY
As this is supposed to be a practical course of instructions we would not be doing our job if
we didn't spell out the latent dangers that can occur when you are working on rotating
machinery. The following "safety-rules" should be adhered to in all cases of maintenance,
but especially when attending to couplings.
THE RULES (to keep you alive and well)
1. Never work on a machine that has not been isolated and safety tagged at the main
control unit.
2. Never remove a safety guard until the machine is stationary.
3. Always use the correct lifting equipment to raise or lower heavy machines.
4. Keep the work area clean and tidy to prevent you from tripping, slipping or
damaging equipment.
5. Clean up any oil or liquid spillage to prevent slipping or, if applicable, to reduce a fire
hazard.
6. Don't use petrol or flammable liquids to clean parts - especially electric motor
parts.
7. Ensure that all tools or equipment are removed from coupling area before the
machines are re-connected to the power supply.
8. Replace safety guards or covers before running the machinery.
9. Notify your Supervisor in the event of any malfunction (e.g. machine fault, fire or
personal injury).
10. Exercise common sense -we all have some somewhere!
NOW WATCH THE VIDEO.
TURN PAGE FOR SELF-CHECK EXERCISE.
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12
TASK NO. 1 - MCA-1
SELF TEST EXERCISE
Answer the following questions, then check your answers against the Resource Notes.
1. Name two types of rigid couplings.
i)_______________________________________________________
(ii)______________________________________________________
2. What does an Elastomeric coupling contain that others do
not?
________________________________________________________
3. What would the term "Perfect Alignment" suggest?
________________________________________________________
4. What two factors can disturb alignment?
i)_______________________________________________________
(ii)______________________________________________________
5. What two "parameters" of miss-alignment have been
mentioned so far?
i)_______________________________________________________
(ii)______________________________________________________
6. What is a "half-coupling"?
________________________________________________________
7. What two things must first be checked before any
alignment correction is attempted?
i)_______________________________________________________
(ii)______________________________________________________
8. Why does a small gap exist between half-couplings?
________________________________________________________
9. Careless fitting or faulty alignment will result in what? Give
four conclusions.
i)_______________________________________________________
(ii)______________________________________________________
iii)______________________________________________________
(iv)_____________________________________________________
YES
NO
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13
10. List the 10 safety rules mentioned (give short answers).
1. __________________________________________________
2. __________________________________________________
3. __________________________________________________
4. __________________________________________________
5. __________________________________________________
6. __________________________________________________
7. __________________________________________________
8. __________________________________________________
9. __________________________________________________
10. __________________________________________________
TOTAL CORRECT
(CHECK YOUR RESPONSES BY READING THE NOTES OR REPLAYING THE VIDEO.)
PROCEED TO TASK NO. 2.
YES
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14
TASK NO. 2 - MCA-2
PREPARATION FOR ALIGNMENT
INSTRUCTIONS
o Read the resource notes before viewing the video portion.
o Proceed as you did in Task No. 1 and end by doing the self test and suggested
exercises.
o Ask your Instructor for the Criterion Test to conclude this programme.
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15
RESOURCE NOTES
TASK NO. 2 MCA-1
PREPARATION FOR ALIGNMENT
Whenever machinery has been disconnected from its coupling for maintenance or other
reasons it follows, that upon re-installing, we will have to re-align the units.
No matter what coupling type is encountered, certain conditions have to be met prior to
actually getting down to aligning the coupling.
Before we touch on specifics, let's overview some general rules for machinery installation.
INSTALLATION PRACTICE
1. The driven unit is always installed first, the motor (Le. the driving unit) is then
aligned to the driven unit's shaft.
2. A "solid-base" must be obtained on both driven unit and the motor. This that all
mounting feet (pedestals), the base plate mounting pads etc., must be flat and there
must be zero "rocking".
3. Ensure that motor adjusting bolts, (jacking bolts) are in good order and that the
motor is able to be moved. Utilise proper lifting apparatus as and when necessary.
4. Mount units using zero shims.
DETERMINING MOTOR ROCK
1. Use a 0,05 mm feeler gauge to check if any gap exists under motor feet - (N.B:
Motor is resting on its own - bolts not tightened).
2. If any foot is not resting / touching base plate then measure (with a feeler
gauge) the gap that exists.
3. Obtain or make a shim of corresponding thickness and insert under the foot.
Ensure that shim is slightly larger than the foot (allow ± 1 mm excess).
Fig. 21
Once you have established a "solid base" then alignment procedures can begin. The actual
procedures will vary according to coupling types. We will cover various procedures in
programmes 2 and onward. This then concludes programme one.
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16
Fig. 22
NOW WATCH VIDEO MCA-1 TO CONCLUSION.
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17
TASK NO. 2 - MCA-1
SELF TEST EXERCISE
This is a practical exercise to be done on a training model in your training centre workshop.
INSTRUCTIONS
Ask your Instructor for a working model to use and do the following:
1. Set up the driven unit and motor onto the base as described in the video.
2. Cut and insert the necessary shims to eliminate motor rock.
3. Tighten down the base bolts ensuring you leave a ± 3 mm gap between coupling
halves.
CHECK YOUR WORK AGAINST THE CHECKLIST ON NEXT PAGE.
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18
SELF CHECK
o Was "driven" unit installed and secured first?
o Is the motor resting on packs of shims?
o Has a "solid-motor-base" been obtained?
o Are shims made to foot size or slightly larger?
o Does a ± 3 mm gap exist between the half-couplings?
ONCE YOU HAVE COMPLETED THIS TASK,
THEN HAVE YOUR INSTRUCTOR CHECK YOUR WORK.
YES
NO
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19
PROGRAMME NO. 2 MCA-2
"BIBBY" COUPLINGS
OBJECTIVE
At the end of this programme you will be able to:
o Identify.
o Dismantle.
o Inspect.
o Re-assemble.
o Align.
A typical "Bibby" or "Steel Grid Coupling".
AIM OF THIS PROGRAMME
This programme has been produced to offer you a visual and written explanation for
performing typical routine maintenance tasks on a Bibby type coupling.
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20
TASK NO. 1 - MCA-2
COMPONENT PARTS
"BIBBY" COUPLINGS
INSTRUCTIONS
o Read the Resource notes beginning over page.
o Obtain video No. MCA-2.
o Watch the video up to the first "Practical" time break.
o Stop the video and do the self test which appears after the Resource notes.
o Continue on to Task No. 2, once you have completed Task No. 1.
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21
RESOURCE NOTES
TASK NO. 1 MCA-2
"BIBBY" COUPLING
DISMANTLE, CLEAN, INSPECT AND ASSEMBLE
The so-called "Bibby" Coupling is more correctly referred to as a "Grid" Coupling. Several
designs are manufactured but the primary construction is similar in each. Two of the
commonest types are illustrated below:
Fig. 23 Vertical Shroud Fig. 24 Horizontal Shroud
In effect the coupling consists of "ribbed" or "slotted" half-couplings. A steel spring or grid is
employed to connect the half-couplings. The spring may be one full segment or in several
segments. The sectional shape of the spring is such that it occupies the full depth of the half-
coupling slots.
A two piece "shroud" envelopes the coupling serving to retain lubricant, usually grease, and
to seal out dirt arid dust. Oil seals, usually 'O' rings, are provided for positive dirt exclusion.
A gasket may be employed between the two shroud contact faces.
Fig. 25
GENERAL MAINTENANCE PROCEDURES
o Grid couplings are normally lubricated on a weekly basis via the grease nipple.
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22
o Only clean, water-free grease should be used.
o Every 12 months the couplings should be dismantled, cleaned, inspected and re-
assembled using new parts as necessary.
DISMANTLE (PROCEDURE)
1. Ensure plant is isolated and tagged.
2. Remove safety guard and place it out of harm's way.
3. Remove shroud bolts, nuts and washers. Store them to prevent loss.
4. Carefully move shrouds and slide them out of the way. Ensure that you do not
damage the oil seals during this process.
5. Carefully prise spring out of coupling slots.
N.B: Do not apply. force onto spring that might damage the slots, spring or
couplings. In other words, avoid digging the springs out with a chisel etc. and
do not use a hammer on the coupling.
WASH AND INSPECT
1. Using a suitable degreasing agent (not a flammable liquid) clean all parts. An old stiff
paintbrush is ideal to clean out the slots in half-couplings.
2. Inspect all parts for any damage or wear.
3. Insert spring (now clean) into the slots and check if it fits neatly without "play"
which would indicate worn slots or springs (or both).
4. Inspect the seals and gasket for damage and wear.
5. Inspect the shroud covers for any damage.
6. Inspect the fasteners (bolts, nuts and washers) and renew them if they are in
anyway damaged or worn.
ASSEMBLE COUPLING
At this stage it is assumed that alignment has not been disturbed. Normally alignment would
be checked and set before assembly. This procedure (alignment) begins in Task No. 2 of this
programme.
ASSEMBLY PROCEDURE
1. Insert spring or segments into coupling, without force.
2. Pack around spring the recommended type of grease.
3. Slide shrouds together, carefully, to cover the coupling, then fit two bolts (opposites)
- finger-tight only.
N.B: Care must be taken to avoid damaging '0' ring seals when shrouds are moved.
4. Fit all other shroud bolts/nuts then tighten them up evenly in a cross-star pattern to
avoid distortion.
5. Wipe off surplus grease and then replace the safety guard.
6. Inform your Supervisor that job is done, in order to effect electrical
connections.
NOW WATCH THE VIDEO DEMONSTRATION.
TURN PAGE FOR SELF CHECK EVALUATION.
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23
SELF CHECK EXERCISE & EVALUATION
TASK NO. 1 - MCA-2
INSTRUCTIONS
o Ask your instructor / supervisor to allocate you a Bibby coupling unit (or training
simulator).
o Perform a full maintenance service on the coupling as you learned in Task No. 1
Resource notes and video programme.
o Have your instructor check your work before fitting safety covers.
o Evaluate your work using the criterion check list on the next page.
TURN PAGE FOR CRITERION CHECK LIST.
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24
CRITERION CHECK LIST
TASK NO. 1 MCA-2
Tick the correct response, YES or NO.
1. Was the equipment electrically isolated according to company
rules?
2. All parts were properly stored after removal.
3. Non-flammable cleaning fluid used.
4. All parts inspected for damage or wear.
5. List below all part names and condition Part Condition.
Part Condition
___________________ __________________________________________
___________________ __________________________________________
___________________ __________________________________________
___________________ __________________________________________
___________________ __________________________________________
___________________ __________________________________________
___________________ __________________________________________
6. Spring inserted correctly without force.
7. Shrouds installed correctly without seal damage.
8. Correct grease used to pack coupling.
9. Fasteners tightened securely and evenly.
10. Supervisor / lnstructor checked your work.
IF YOUR SUPERVISOR / INSTRUCTOR HAS CHECKED YOUR WORK AND CONFIRMED THAT IT IS OF
CORRECT STANDARD,
THEN PROCEED TO TASK NO. 2 OVER PAGE.
YES
NO
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25
TASK NO. 2 - MCA-2
AXIAL CORRECTION OF BIBBY COUPLING
INSTRUCTIONS
o Read the Resource notes beginning over page.
o Then play video from where you last stopped at the "practical logo".
o Stop video at next Practical logo (i.e. at the end of Axial alignment).
o Do the practical exercise for Task No. 2.
NB: Remember that you can, if you wish, play the video more than once in order
to fully understand how to do the job.
TURN PAGE FOR RESOURCE NOTES.
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26
RESOURCE NOTES
TASK NO. 2 MCA-2
BIBBY COUPLING -AXIAL ALIGNMENT (TOP AND BOTTOM)
NOTE: The procedures shown are typical, however actual tolerances quoted may vary
between manufacturers or your company standards.
PROCEDURE - (PRELIMINARY ALIGNMENT)
o Ensure that motor rock has been eliminated. (see Task 2 -Programme
MCA-1).
o Position motor until a ± 3 mm gap is obtained between couplings.
o Use a suitable small straight-edge (i.e. a 150 mm steel engineer's rule) and move the
motor until the circumferential edges of both half-couplings lie parallel to the steel
rule.
o Secure the motor's hold down bolts.
N.B: (Side adjusting screws, if fitted, must be loosened all the way out.)
The first correction is always AXIAL.
In theory the gap between half couplings is measured at the top and bottom. The difference
is noted. A simple formula is then applied to derive the thickness of shims required to either
lower or raise the half coupling on the motor.
The formula is: t = A x Cd
D
where: t = Shim thickness.
A = Gap variation (difference).
D = Half coupling diameter.
Cd = Centre distance between hold down bolts on motor.
Fig. 26
The instruments used to measure gap 'A' can be, clock gauge (D.T.I.), taper gauge or vernier.
We shall use D.T.I. gauges as these provide greater accuracy.
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27
PROCEDURE - (AXIAL MEASUREMENT)
o Slip a segment of coupling spring into slots to enable the two half-couplings to be
rotated together.
o Bolt / secure gauge clamp onto motor coupling.
o Connect gauge to end of clamp.
o Arrange plunger to contact "driven" coupling parallel to shaft.
o Adjust plunger to provide a nominal reading of 2 mm on the small pointer.
o Rotate coupling so that gauge is top of coupling (i.e. at the 12 o'clock position).
o "Zero" the clock.
o Carefully rotate the coupling 180 degrees (i.e. until the gauge is at the 6 o'clock
position).
o Note the reading which is the 'A' factor.
o Also note whether the needle moves in a positive (+) or in a negative (-) direction.
N.B: This will determine where the shims will be fitted, which we'll cover in a
moment.
o Now that you have the 'A' dimension, calculate the shim thickness by applying the
formula:
t = A x Cd
B
Naturally you will have to actually measure the dimension D (the half-coupling diameter)
and Cd (the distance between motor held down bolt centre).
EXAMPLE (AXIAL CORRECTION)
Measured dimension 'A' = 0,20 mm
Coupling diameter D = 100 mm
Motor bolt centres Cd = 230 mm
Apply the formulae
then t = 0,20 x 230
100
t = 0.46 mm
Next we must establish where to put the shims. The rule is this -if the gap between
couplings is bigger at the top then shims are fitted on the rear of motor (Le. under the back
feet). Conversely shims are fitted under the frQn1 feet if the gap between couplings is
bigger at the bottom
It follows that the gap is bigger at the top if the dial gauge reads negative (-) at the
bottom. By simple deduction if the gauge is positive (+) then the gap is bigger at the bottom.
o Cut and fit the necessary shims (as calculated) under the relevant pair of motor feet.
To do this the motor bolts have to be loosened, so, once the shims have been
installed re-align the half-couplings with the edge of a steel rule and ensure
that a ± 3 mm gap exists. Tighten down the motor bolts evenly and then ...
o Re-measure the top / bottom gap with a clock (dial) gauge as before.
o Re-shim as necessary until a maximum of 0,05 mm run-out is achieved. (Obviously
the closer you can get to zero run-out, the better).
Back to Table of Contents
28
The AXIAL correction has now been accomplished. However, we must still attend to the
RADIAL correction which is covered in Task No. 3 of this programme.
At this time, watch the video demonstration for AXIAL adjustment and then perform the
practical self check exercise.
TURN PAGE FOR SELF CHECK EXERCISE INSTRUCTIONS.
Back to Table of Contents
29
SELF CHECK EXERCISE
TASK NO. 2 - MCA-2
INSTRUCTIONS
o Perform a top and bottom AXIAL alignment on a bibby type coupling in your training
centre or on a unit provided by your Instructor / Supervisor.
o Have your Instructor / Supervisor check your finished work.
o Evaluate your work using the criterion check list on the next page.
TURN PAGE FOR CRITERION CHECK LIST.
Do not work on a LIVE unit unless you have received clearance /
permission and all safety regulations have been complied with.
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30
CRITERIA TEST CHECK LIST
TASK NO. 2 MCA-2
Tick the correct response, YES or NO.
o Motor rock fully eliminated.
o A ± 3 mm gap is present between couplings.
o Preliminary alignment set.
o Axial alignment within 0,05 mm tolerance.
o Motor hold-down bolts are secure.
IF YOU HAVE ACHIEVED ALL THE ABOVE CRITERIA THEN CALL YOUR INSTRUCTOR / SUPERVISOR TO
CHECK YOUR WORK.
TURN PAGE TO BEGIN TASK NO. 3.
YES
NO
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31
TASK NO. 3 - MCA-2
RADIAL CORRECTION
TOP AND BOTTOM OF BIBBY COUPLING
INSTRUCTION
o Read the resource notes beginning over page.
o Play video from where you last stopped.
o Stop video at next practical logo.
o Do the practical exercise for Task No. 3.
Back to Table of Contents
32
RESOURCE NOTES
TASK NO. 3 MCA-2
RADIAL -TOP AND BOTTOM ADJUSTMENT
In this check and adjustment a similar procedure to the axial connection is employed. The
main difference is that the clock gauge (D.T.I.) is now set against the periphery of the driven
half-coupling.
In practice we actually introduce a second clock gauge and attach it to the gauge clamp as
illustrated below. The axial gauge remains in position so that we can keep an eye on it
should we accidentally move the axial setting.
Fig. 27
Procedure for Radial correction (top and bottom):
o Rotate coupling to bring it to top (i.e. 12 o'clock position).
o Zero the gauge.
o Rotate coupling 180⁰ (i.e. to 6 o'clock position), take a reading and note the needle
movement. (i.e. is it in a positive (+) or negative (-) direction).
If the needle moves in a (+) direction then this indicates that the motor is high. If movement
is (-) then motor is low.
If motor is high then shims will have to be removed. Conversely shims will have to be fitted
if motor is low.
The shim thickness is established by halving the variance between top and bottom reading
on the clock gauge.
For example if variance is equal to 0,50 mm then shims of 0,25 mm will need to befitted or
removed accordingly.
o A major point of note is that whether shims are fitted or removed we must treat
each foot (i.e. all 4 feet) of the motor identically, otherwise we will disturb the axial
setting.
o Loosen the motor hold down bolts and insert or remove shims to the thickness value
required.
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33
o Re-align half-couplings against the 150 mm engineer's rule or straight-edge.
o Secure hold-down bolts -being careful not to move the motor as you do this.
o Check top and bottom reading on D.T.I. (clock gauge) and establish a maximum
radial run out of 0,05 mm. Naturally a zero reading would be ideal.
Up to this time we have been concentrating all our efforts to top and bottom of the
coupling. In other words we have been viewing the alignment side-on. Now we must turn
our attention to a viewing point above the coupling and attend to axial and radial
corrections on the side of the couplings.
Virtually all motor mountings provide a method of adjusting side-ways movement. Typical is
the "side-adjusting screw" method shown in the following illustration:
Fig. 28
Jacking or side-adjusting screws on motor frame allow for sideways adjustment.
We shall discuss the necessary procedures during Task No. 4.
o For now, continue watching the video to see the radial - top to bottom correction
being demonstrated. Then perform the self-check exercise on the following page.
TURN PAGE FOR SELF CHECK EXERCISE INSTRUCTIONS.
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34
SELF CHECK EXERCISE
TASK NO. 3 - MCA-2
INSTRUCTIONS
o Perform a top and bottom Radial correction on the bibby coupling last worked on for
the Axial correction.
o Have your Instructor / Supervisor check your finished work.
o Evaluate your work using the criterion check list on the next page.
TURN PAGE FOR CRITERION CHECK LIST.
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35
CRITERIA TEST CHECK LIST
TASK NO. 3 MCA-2
Tick the correct response, YES or NO.
o Is top / bottom radial alignment within specification of 0,05 mm?
o Is coupling preliminary alignment re-checked and correct?
o Are motor bolts secured?
o Is AXIAL top / bottom alignment still in specification?
IF ALL THE ABOVE CRITERIA ARE MET THEN HAVE YOUR INSTRUCTOR / SUPERVISOR CHECK YOUR
WORK BEFORE PROCEEDING TO TASK NO. 4.
TURN PAGE TO BEGIN TASK NO. 4.
YES
NO
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36
TASK NO. 4 - MCA-2
AXIAL AND RADIAL SIDE CORRECTIONS
ON A BIBBY TYPE COUPLING
INSTRUCTIONS
o Read the resource notes beginning over page.
o Play video from where you last stopped.
o Play video to end.
o Do the practical exercise for Task No. 4.
o Ask your Instructor / Supervisor for the Criterion test upon completing all practical
exercises.
Back to Table of Contents
37
RESOURCE NOTES
TASK NO. 4 MCA-2
In this section of the programme we shall complete the alignment procedure. Our attention,
to begin with, will be concentrated on side adjustments. To do this we view the coupling
from above.
Again we begin by tackling the AXIAL problem first.
(N.B: Ensure that side-adjusting screws are fully loosened.)
AXIAL ADJUSTMENT AT SIDE - PROCEDURE
o Turn the coupling until clock gauges are at the side of the coupling (i.e. 90⁰ from
vertical).
o Adjust the gauge to zero (we are concentrating on the gauge which is parallel to the
shaft).
o Rotate shaft by 180⁰ to bring gauge to a level position opposite where it was.
NB: 1) Should you not be able to read the gauge because its face is
downward, ...... place a mirror below it, remembering of course that
things will look backward but you'll still be able to figure out how
much the needle deflects and which way it moves (by observing + or -
signs).
2) Some people prefer to begin by zeroing the gauge -face down using
the mirror ... then when it's rotated 180⁰ you'll have no problem
reading it.
o Now establish which side (if any) has the largest gap.
o Then by turning in the relevant side adjusting screws we can 'swing' the motor to
correct the gap.
Let's discuss this in diagram form.
Fig. 29 SITUATION NO. 1 (AXIAL)
REMEDY
o Loosen motor hold down bolts - take care not to move motor.
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38
o Screw in side adjustment screw 'C' until it contacts motor foot. Do this by hand only -
no force to be exerted onto motor.
o Next, screw in adjusting screw 'B'.
NB: Ensure screws 'A' and 'D' are fully out.
o Adjust on screw 'B' until gap decreases to within 0,05 mm spec. (or zero).
o Now, by hand only, screw in adjusters 'A' and 'D' until they make contact with motor
feet (NO force exerted).
Fig. 30 SITUATION NO. 2 (AXIAL)
Situation - Gap widest on right side of motor.
REMEDY
o Loosen motor hold-down bolts.
o Screw adjusting screw 'A' in to contact foot, no pressure exerted.
o Ensure screws 'B' and 'C' are fully wound out.
o Adjust gap with screw 'D' until spec. of max.. 0,05 mm is obtained (or zero if
possible).
o Screw in adjusters 'B' and 'C' to just contact motor feet.
o Tighten hold-down bolts.
Once you have established correct axial adjustment proceed with radial adjustment.
The procedure is as follows:
o Observe clock gauge that is against the driven half-coupling's side (i.e. the one
contacting the outer edge).
o Zero the gauge at 90⁰ to vertical (i.e. at the 3 or 9 o'clock position).
o Rotate 180⁰ and read the deflection.
o Make the necessary adjustments which, again, we'll describe using diagrams.
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39
Fig. 31
Situation - Motor is too far to the right (assessed by the fact that a negative deflection of
clock gauge was noted).
REMEDY
o Loosen motor hold-down bolts.
o Slacken off adjusting screws 'C' and 'D'.
o Carefully turn screws 'A' and 'B' in by exactly the same amounts each. This takes a bit
of skill, but begin by turning in very small increments of approximately ⅛ of a turn on
each screw.
o Check the gauge reading after each time you have made a move of the adjusting
screws (A and B).
o When the desired radial run out of 0,05 mm, or less has been achieved, then tighten
the motor hold-down bolts and re-check the run-out.
N.B: It is standard practice to leave the adjusting screw out once the motor hold
down bolts have been finally tightened.
Fig. 32
Situation - Motor is too far to the left:
REMEDY
o Ensure adjusting screws 'A' and 'S' are loosened.
o Tighten screw 'C' and '0' evenly as mentioned in previous situation.
o Take gauge readings after each adjustment.
o Tighten hold down bolts when a maximum 0,05 mm run-out has been achieved.
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40
CONCLUSIONS
In theory the coupling should be in alignment, however in practice a lot of things tend to go
wrong each time the motor is loosened to effect any movement. It will be appreciated that
we are dealing with very small angles and movements, therefore we must make every effort
not to bump or move any part of the set-up during the alignment procedure, especially
whilst the motor's hold-down bolts are loose.
Further, inaccurate adjusting of side screws on radial adjustments will cause the axial
adjustment to move off-line. Owing to the fact that one thing affects another, the skill of
alignment is greatly affected by your patience. It is certainly not a job to be tackled when
you're under pressure!
Remember the following tips:
o Always make .axial corrections first.
o Check axial movement again after you've made a radial adjustment.
o Adjust top and bottom factors first, then adjust side factors.
o Take readings only when the motor hold-down bolts have been secured.
o Always maintain the specified gap between half-couplings.
o Slacken off and lock side-adjuster screws after the motor has been finally secured by
its hold-down bolts.
NOW WATCH THE VIDEO DEMONSTRATION
THEN DO THE SELF CHECK EXERCISE.
TURN PAGE FOR SELF CHECK EXERCISE INSTRUCTIONS.
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41
SELF CHECK EXERCISE
TASK NO. 4 - MCA-2
INSTRUCTIONS
o Complete the alignment exercise on the bibby coupling that you have been
previously working on.
o Have your Instructor / Supervisor check your finished work.
o Evaluate your work using the Criterion Check List on the next page.
TURN PAGE FOR CRITERION CHECKLIST.
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42
CRITERIA TEST CHECK LIST
TASK NO. 4 MCA-2
Tick the correct response, YES or NO.
o Is side axial adjustment in spec.?
o Is side radial adjustment in spec.?
o Is motor properly secured?
o Is half-coupling gap correct?
o Have side adjusting screws been backed off?
IF ALL THE ABOVE CRITERIA HAVE BEEN MET THEN ASK YOUR INSTRUCTOR / SUPERVISOR TO
CHECK YOUR WORK.
ASK YOUR INSTRUCTOR FOR THE CRITERION TEST FOR THIS PROGRAMME MCA-2 TO COMPLETE
THIS PROGRAMME OF INSTRUCTION.
YES
NO
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43
PROGRAMME NO. 3 - MCA-3
"FENNA-FLEX" COUPLINGS
OBJECTIVE
At the end of this programme you will be able to:
o Identify.
o Dismantle.
o Inspect.
o Re-assemble.
o Align.
a typical "shear" coupling of Fenna-Flex design.
AIM OF THIS PROGRAMME
This programme has been produced to offer you a visual and written explanation for
performing typical maintenance aspects on Fenner type "rubber tyre" couplings.
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44
TASK NO.1 - MCA-3
COMPONENT PARTS
"FENNA-FLEX" COUPLINGS
INSTRUCTIONS
o Read the Resource notes beginning over page.
o Obtain Video No. MCA-3.
o Watch video through until the first musical break -"PRACTICAL" will be on screen.
o Stop the video at this time and perform the first exercise as described after the
resource notes.
o When you have completed Task No. 1 you can then proceed to Task No. 2.
TURN PAGE FOR RESOURCE NOTES.
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45
RESOURCE NOTES
TASK NO. 1 MCA-3
"FENNA-FLEX" COUPLINGS
(IDENTIFY, DISMANTLE, CLEAN, INSPECT AND ASSEMBLE.)
IDENTIFICATION AND PART NAMES
The popularity of "Fenna-Flex" couplings cannot be overlooked. Such couplings are relatively
easy to maintain and install.
Misalignment and torsional shock loads are absorbed by "shear" deflection in the rubber
component (the resilient element).
Fig. 33
These couplings, in various sizes, are capable of transmitting loads in excess of 2 500 kw.
and can be used on shaft diameters up to 200 + mm.
Principle components of a "Fenna-Flex" coupling are shown in diagram.
Fig. 34
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46
DISMANTLING PROCEDURE
o Ensure that unit is isolated from mains power supply.
o Remove coupling guard and store it out of the way.
o Loosen all the coupling flange set-screws.
o Remove the resilient member (tyre) being careful not to damage it.
NB: Unless the coupling is being totally replaced it is not necessary to remove the
half-couplings.
o Do not disturb taper-lock bush screws.
INSPECTION PROCEDURE
As is to be expected, we are looking for any condition of each component that could cause a
future malfunction. Clean and inspect all surfaces of the metal parts ensuring that no high
spots, burrs or corrosion build-up is left, paying particular attention to:
o The mating surfaces between flanges and half-couplings.
o The contact surfaces of the resilient element.
Further, ensure that the flange / coupling set screws have no damaged threads or show
signs of corrosion.
Inspect the resilient element for any signs of wear, cracking or rubber deterioration. The
resilient element should be removed if it is in any way damaged.
Do not use solvents to clean the resilient element; rather use a water moistened clean rag
to remove any debris or dirt.
ASSEMBLY
o Fit the resilient element (tyre) over the coupling flanges ensuring that it seats
properly all around its beading area.
NB: It may sometimes be necessary to use a rubber or 'soft' mallet to
strike the element around its circumference in order to seat the
beading onto the flanges.
o Align the flange to the coupling half and fit the set screws. Tighten them evenly in a
"star" or "criss-cross" pattern to ensure that mating surfaces align squarely. Do this
to both flanges. Secure the set screws to the recommended torque.
o Check that the recommended gap exists in the rubber element:
Size 40 - 120 = 1,5 mm gap
Size 140 - 160 = 3,00 mm gap
Size 180 - 250 = 5,00 mm gap
TURN PAGE FOR SELF CHECK EVALUATION.
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47
SELF CHECK EXERCISE AND EVALUATION
TASK NO. 1 - MCA-3
INSTRUCTIONS
o Ask your Instructor / Supervisor to allocate you a "Fenna-Flex" type coupling unit on
a training simulator.
o Dismantle the unit.
o Inspect the components and report any faults to your Instructor / Supervisor.
o Assemble the unit.
o Have your Instructor / Supervisor check your work before fitting safety guards.
o Evaluate your work using the criterion check list on the next page.
TURN PAGE FOR CRITERION CHECK LIST.
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48
CRITERION CHECK LIST
TASK NO. 1 MCA-3
Tick the correct response, YES or NO.
1. Was the unit totally isolated from main supply?
2. Coupling dismantled without damage.
3. All metal parts fully cleaned and debarred etc.
4. All components inspected for damage.
5. List all components below - report on condition.
PART CONDITION
______________________ ______________________________________
______________________ ______________________________________
______________________ ______________________________________
______________________ ______________________________________
______________________ ______________________________________
6. Tyre fully seated on flanges.
7. Flange cap screws evenly secured / torqued.
IF YOUR INSTRUCTOR / SUPERVISOR HAS CHECKED YOUR WORK AND IS SATISFIED THAT IT MEETS
THE STANDARDS, THEN PROCEED TO
TASK NO. 2 OVER PAGE.
TURN PAGE TO BEGIN TASK NO. 2.
YES
NO
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49
TASK NO.2. - MCA-3
TAPER LOCK DEVICE
INSTRUCTIONS
o Read the Resource notes beginning over page.
o Play video from where you last stopped.
o Stop video at "PRACTICAL" logo.
o Do the practical exercise for Task No. 2.
TURN PAGE FOR RESOURCE NOTES.
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50
RESOURCE NOTES
TASK NO. 2 MCA-3
"FENNA-FLEX" - TAPER-LOCK SHAFT FIXING
In the normal course of events a motor may have to be replaced for purposes of overhaul or
repair. At such times it is normal for a replacement motor to be used. At this time the
coupling is normally removed from the old motor and fitted again onto the replacement.
The procedure for removing and refitting a "Fenna-Flex" coupling half is outlined in these
notes. It is assumed that the motor has been removed from the unit.
PROCEDURE-REMOVAL
1. Before removal - measure the shaft protrusion (if any) between the end of the shaft
and the face of the bushing. Note this figure in order to set the same amount when
you fit the bush onto the replacement motor's shaft.
2. Using an allen-key (sometimes a ring spanner), loosen the hub to bush securing grub
screws by about 4 turns each.
3. Obtain a grub screw that matches the threads of the jacking screw hole (NB: You can
use the hub securing screws if others are not available).
4. Oil the jacking screw and thread it into the jacking-off hole in the hub.
5. Tighten the jacking-screw evenly until the hub releases from its lock against the
bush.
NOTE: When hub is very tight you may have to resort to tapping around the hub
with a 'soft' mallet or copper punch. Strike the hub as close as possible to the bush,
to assist in parting the taper.
6. Remove the assembly from the shaft.
NOTE: It may be necessary to insert a wedge into the split part of the tapered bush
to expand it very slightly. Care must be taken, however, not to overdo this as the
bush can easily break.
PROCEDURE: REPLACING TAPER-LOCK UNIT
1. Clean up any burrs, rust or erosion on contact surfaces using suitable methods (e.g.
smooth file or emery tape).
2. Ensure that both the shaft and the taper bush are free of oil.
3. Align the hub so that its "half-holes" align to the "half-holes" on the bush, and
ensure keyway aligns.
4. Oil the grub screws and thread them carefully into their hole positions. Do not
tighten them yet.
5. Position the "flange" (i.e. the flange that will secure the tyre) over the shaft (so
that it's there when you come to assemble the coupling!).
6. Slip the loosely assembled taper-lock assembly onto the shaft ensuring that it
slides over the key (which you must not forget to fit first!).
7. Position the taper-lock unit to the same depth as you measured before you
took it off the original shaft.
8. Secure the grub screws evenly and alternately to ensure a uniform settling.
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51
9. Give the bush a couple of knocks with a soft punch -then re-tighten the grub
screws (this will ensure a positive lock).
10. Place a little grease into the grub screw head/holes to prevent dirt entering.
REFER TO DIAGRAMS OVER PAGE.
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52
Fig. 35
A typical taper-lock assembly. (Note aligning marks - which the artisan has made for ease of
re-assembly.) Other details of a typical taper-lock unit shown below.
Fig. 36
NOW WATCH THE VIDEO DEMONSTRATION.
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53
SELF CHECK EXERCISE AND EVALUATION
TASK NO.2 - MCA-3
INSTRUCTIONS
o On your allocated "Fenna-Flex" unit remove, inspect and re-assemble the taper-lock
assembly as demonstrated.
o Have your Instructor / Supervisor check your completed work.
o Your work using the Criterion check list on the next page.
TURN PAGE FOR CRITERION CHECK LIST.
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54
CRITERION CHECK LIST
TASK NO. 2 MCA-3
Tick the correct response, YES or NO.
1. Was machinery total isolated from power supply?
2. Was shaft protrusion noted before dismantling?
3. Were hub and bush removed without damaging?
4. Were both shaft and bush inspected and dressed up as required?
5. Was the unit re-positioned to the depth as removed?
6. Did you oil the screws when jacking and replacing?
IF YOUR INSTRUCTOR / SUPERVISOR HAS CHECKED YOUR WORK AND IS SATISFIED THAT IT MEETS
THE STANDARD, THEN PROCEED TO
TASK NO. 3 OVER PAGE.
TURN PAGE TO BEGIN TASK NO. 3.
YES
NO
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55
TASK NO. 3 - MCA-3
FENNA-FLEX COUPLING-ALIGNMENT
INSTRUCTIONS
o Read the Resource notes beginning over page.
o Play video from where you last stopped.
o Stop the video at "PRACTICAL" logo.
o Do the practical exercise for Task No. 3.
TURN PAGE FOR RESOURCE NOTES.
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56
RESOURCE NOTES
TASK NO. 3 MCA-3
FENNA-FLEX - ALIGNMENT
NOTE: The general procedure for performing alignment correction on Fenna-Flex couplings
is the same as for Bibby type couplings. That is to say that the pre-alignment
methods and checking axial and radial alignment, using clock gauges can be
employed.
However for purposes of providing you with an alternative method, this programme will
make use of other measuring instruments namely, callipers.
The criteria for an acceptable alignment on Fenna-Flex couplings are:
o No motor rock.
o Gap between flanges is in accordance with manufacturer's specification.
o Run-outs on axial and radial parameters not to exceed 0,05 mm.
PROCEDURES - INSTALLATION
o Re-position motor onto its base ensuring that:
(i) Motor rock is eliminated.
(ii) Preliminary alignment, using a 150 mm steel rule or straight-edge, is
achieved.
(iii) Shafts do not touch (leave a gap of at least 3 millimetres).
ESTABLISHING FLANGE DISTANCES
Fig. 37
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57
In the diagram above, an inside-calliper is being used to determine the distance between
flanges. If you look at the diagram over page you will see the dimension "5". This is the
dimension being measured by the inside-calliper.
The chart (Physical Characteristics and Dimensions) gives this dimension as L5 in the column
marked with an * (see chart on Page 62).
Note which coupling size you are working on. This is normally marked on the rubber
element (tyre) as F and a number. So, as an example, a coupling marked as F80 would have
a L5 distance of 43 mm.
TIP: The flange distance gap (i.e. L5 setting) is normally adjusted after all alignment
corrections have been made. Adjustment is effected by moving one of the taper-lock
units on its shaft.
MAJOR DIMENSIONS (FENNA-FLEX COUPLINGS)
Taper-Lock
Bored to size
Coupling
Size
Bush
No.
Max
Bore
Coupling
Size
Max
Bore
d1
d2
d3
L1
L5
Max
r/min
F40
1008
25
F40B
32
105
82
-
66
22
4500
F50
1210
32
F50B
38
133
100
79
75
25
4500
F60
1610
42
F60B
45
165
125
103
83
33
4000
F70
1610
42
F70B
50
187
144
76
100
40
3600
F80
2012
50
F80B
65
211
167
95
107
43
3100
F90
2517
60
F90B
76
235
188
111
136
46
2880
F100
2517
60
F100B
85
254
216
124
138
48
2600
F110
2517
60
F110B
90
279
233
140
135
45
2300
F120
3020
75
F120B
102
314
264
152
151
49
2050
F140
3535
90
F140B
127
359
311
195
203
25
1800
F160
4040
100
F160B
140
402
346
216
226
22
1600
F180
4545
110
F180B
165
470
394
252
261
33
1450
F200
4545
110
F200B
180
508
429
267
261
33
1300
F220
5050
125
F220B
190
562
474
289
294
40
1100
F250
5050
125
F250B
220
628
532
310
300
46
960
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58
Reference dimensions - Fenna-Flex Couplings.
AXIAL ALIGNMENT (TOP AND BOTTOM)
NOTE: That the tyre is not installed during the alignment procedures.
PROCEDURES
o Perform a basic pre-alignment using a 150 mm steel rule.
o Mark each coupling half with a chalk or paint line so that the marks correspond.
o Measure the distance 15 at the top of the coupling. This is done with a vernier
calliper or if need be, with an inside calliper then measured off with a micrometer.
o Rotate both coupling halves by 180 degrees ensuring that your chalk/paint marks
remain together (i.e. they correspond).
o Measure the distance 15 at the bottom of the coupling.
o Calculate the difference.
o Establish if gap is wider at top or bottom.
o Fit shims under front or rear feet as necessary. Calculate shim thickness using the
formula shown in programme No. MCA-2, i.e.:
t = A x Cd
D where
A = Difference measured.
D = Diameter of flange (d2 on dimension chart).
Cd = Distance between bolt centres, on motor length.
NOTE: - If gap is wider at the top - fit shims under rear feel.
- If gap is wider at the bottom - fit shims under front feel.
o Re-check axial gap (top and bottom) after:
a) Shims have been installed.
b) Motor hold-down bolts have been secured.
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59
o Continue adjustment until a 0,05 mm maximum deviation between top and bottom
has been achieved.
RADIAL CORRECTION (TOP AND BOTTOM)
o Rotate coupling such that the chalk mark / paint marks are corresponding at the 3 or
9 o'clock position.
o Place a rule or straight-edge across top of coupling halves.
Fig. 39
o Using a feeler-gauge or a taper-gauge measure any gap and note this.
o Determine whether motor pulley is high or low (NB: It is assumed that both
couplings are of the same diameter).
o Cut shims of thickness measured (if motor is low) and insert under all 4 feet
(Conversely remove shims of corresponding thickness from all 4 feet if motor is
high).
o Re-check:
a) Preliminary alignment.
b) Radial alignment (top / bottom).
AXIAL CORRECTION -AT SIDES
Note that we have been viewing the coupling from the side for "top and bottom" correction.
Now we are observing the coupling from above for "side" correction.
Fig. 40
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60
PROCEDURE
o Ensure chalk / paint marks are aligned and at the top.
o Measure distance between flanges at 90⁰ from vertical (i.e. at 3 or 9 o'clock).
o Rotate coupling 180⁰ (keep marks together).
o Measure distance between flanges at opposite side (i.e. 180⁰ from 1st measuring
position).
o Calculate and determine:
a) The difference between gap dimensions.
b) The side which is widest.
o Use the side-adjusting screws to move the motor as we discussed in programme No.
MCA-2 to reduce the wide gap to spec.
(Refer to Page No. 20 for a refresher on these details if you need to.)
o Re-check the axial correction once the motor hold-down bolts have been re-secured.
Again the observation is from the top and adjustment is effected with side adjusting screws.
PROCEDURE
o Set chalk / paint alignment marks to top of coupling such that they align.
o Set a straight-edge alongside of coupling at a position 90° from vertical (i.e. at 3 or 9
o'clock position).
o Measure or assess the gap between coupling halves.
o Use side adjusting screws to shift the motor as necessary -remembering to ensure
that you pay careful attention to the fact that both screws are moved by exactly the
same amount.
(See Page No. 41 for details which apply to all alignment methods.)
o Secure motor hold-down bolts.
o Re-check axial and radial parameters again just to ensure nothing moved.
o Leave side-adjusting screws loose (Lock up on frame but ensure they are not
contacting the motor).
o Replace the resilient element (tyre) as described in Task No. 1.
o Replace safety guard and remove all tools and instruments.
NOW WATCH THE VIDEO DEMONSTRATION.
TURN PAGE FOR SELF CHECK EXERCISE.
Back to Table of Contents
61
SELF CHECK EXERCISE AND EVALUATION
TASK NO. 3 - MCA-3
INSTRUCTIONS
o On your allocated "Fenna-Flex" unit perform an alignment procedure assuming that
the motor is being renewed / refitted.
o Have your Instructor / Supervisor check your work upon completion.
o Evaluate your work using the Criterion check list on the next page.
TURN PAGE FOR CRITERION CHECK LIST.
Back to Table of Contents
62
CRITERIA CHECK LIST
TASK NO. 3 MCA-3
Tick the correct response, YES or NO.
1. Motor / unit isolated from power supply.
2. Motor rock eliminated with suitable shims.
3. Axial correction within 0,05 mm spec.
4. Radial correction within 0,05 mm spec.
5. Motor secured at foot bolts.
6. Flange dimension set according to the size of coupling (i.e. to
dimension chart).
7. Side adjusting screws back off from motor.
8. Resilient Element (Tyre) correctly installed.
IF YOUR INSTRUCTOR / SUPERVISOR HAS CHECKED YOUR WORK AND IS SATISFIED THAT IT MEETS
THE REQUIRED STANDARDS, THEN YOU MAY CONCLUDE THIS PROGRAMME AFTER DOING THE
CRITERION TEST MCA-3.
ASK YOUR INSTRUCTOR/SUPERVISOR FOR THE NECESSARY CRITERION TEST INSTRUCTIONS.
SPECIFICATION DATA OVERLEAF.
YES
NO
Back to Table of Contents
63
PROGRAMME NO. 4 - MCA-4
ALTERNATIVE ALIGNMENT METHOD
OBJECTIVE
At the end of this programme you will be able to:
o Perform an alignment procedure using simple measuring / assessing equipment in
the form of taper gauges and / or feeler gauges.
AIM OF THIS PROGRAMME
This programme has been produced to offer you a visual and written explanation for
performing an alternative method of assessing machinery alignment using the most basic of
measuring equipment.
Back to Table of Contents
64
TASK NO. 1 - MCA-4
TAPER GAUGE
INSTRUCTIONS
o Read the Resource Notes beginning over page.
o Obtain Video No. MCA-4.
o Watch video through until you see either a "DISCUSSION" or "PRACTICAL" sign.
o Perform the suggested exercise in your workbook or in your training workshop.
TURN PAGE FOR RESOURCE NOTES.
Back to Table of Contents
65
RESOURCE NOTES
TASK NO. 1 - MCA-4
TAPER GAUGE
A taper gauge is a simple measuring instrument designed to enable you to quickly assess the
dimension of gaps, however it must only be used when a gap exists between parallel
surfaces.
It should also be noted that a "taper-gauge" is not a "high-precision" instrument and is not
suitable for use where accuracies or tolerances below ± 0,10 mm are essential (With skilled
use accuracies up to 0,05 mm can be realised with a taper gauge).
A typical taper-gauge is the Starrett No. 270 which is graduated in both metric and imperial.
The metric side provides readings from zero to four (0-4 mm) millimetres with each small
division representing 0,05 mm.
Fig. 41
PRACTICAL APPLICATION
For purposes of assessing alignment at the coupling faces a taper gauge can be used in the
following ways.
NOTE: It is assumed that all pre-alignment checks and motor rock (i.e. solid base) have been
done as you learnt in earlier programmes.
AXIAL TESTS (TOP AND BOTTOM)
o Mark each half-coupling to ensure that they always stay together in the same
relationship.
o Slip the taper gauge into the gap at top and take a reading.
o Rotate both half-couplings 180⁰.
o Slip taper gauge into bottom gap and take a reading.
o Calculate the difference between readings.
o Use the formula for calculating shim thickness required:
(t = A x Cd)
B
Back to Table of Contents
66
Fig. 42 TAKING AN AXIAL READING AT TOP
(NOTE: READ TAPER-GAUGE SCALE AS SHOWN IN THE INSET DIAGRAM).
RADIAL CHECKS (TOP AND BOTTOM)
o Set coupling to align your marks at top.
o Lay a 150 mm rule or a straight edge across the two half-couplings.
o Assess the gap (if any) between bottom edge of straight edge and coupling half using
your taper-gauge.
Fig. 43
Adjust the gap to (near) zero by removing an equivalent amount of shims from under each
motor foot. If the gap exists on the motor side - then add equivalent shims under each
motor foot.
Back to Table of Contents
67
AXIAL ADJUSTMENT (AT SIDES)
Fig. 44
Observing coupling from above:
o Align coupling marks together 90⁰ from vertical.
o Measure gap with taper-gauge and note down.
o Rotate both couplings together by 180⁰.
o Measure gap at position of marks - note down.
o If difference exceeds 0,05 mm make the necessary adjustment using side adjusting
screws (A, B, C, D) after first slackening motor hold-down bolts.
Note that in the diagrams we have exaggerated the motor position for purposes of visual
explanation.
In the illustrated example (Fig. 44) we would correct the axial error as follows:
o Tighten screw D until it contacts motor foot.
o Slacken off screw B.
o Slacken off screw C.
o Tighten screw A to move motor slightly.
o Re-tighten all motor hold-down bolts.
o Re-check gap.
Repeat all above procedures until you have achieved ± 0,05 mm difference between both
sides checked.
Back to Table of Contents
68
RADIAL ADJUSTMENT (AT SIDES)
Fig. 45
(NOTE: THE DIAGRAM ABOVE HAS BEEN EXAGGERATED FOR PURPOSES OF EXPLANATION.)
Procedure for correction, in the illustrated example (Fig. 45) is as follows:
o Loosen and wind-out both screws A and B.
o Tighten up, in exactly equal amounts, screws C and D until gap is near, or on, zero
mm.
o Tighten hold-down bolts and re-check both axial and radial run-outs.
o Make re-adjustments as necessary until a maximum of 0,05 mm axial and radial
error is achieved.
o Upon completion of alignment, and after all motor hold-down bolts have been
secured, then slacken off all the side-adjusting screws (i.e. don't leave them to
remain in contact with the motor's feet during operation).
NOW WATCH THE VIDEO PROGRAMME.
TURN PAGE FOR SELF-CHECK EXERCISE.
Back to Table of Contents
69
TASK NO.1
SELF TEST EXERCISE
This is a practical exercise to be done on a training model in your training centre or
workshop.
INSTRUCTIONS
Ask your Instructor for a suitable coupling to use and then perform the following:
o Perform a full alignment procedure using taper-gauge, feeler-gauge and straight
edge.
o Have your Instructor / Supervisor check your finished work.
o Evaluate your work using the criterion check list on the next page.
TURN PAGE FOR CRITERION CHECK LIST.
Back to Table of Contents
70
CRITERIA TEST CHECK LIST
TASK NO. 1 MCA-4
Tick the correct response, YES or NO.
o Were the pre-alignment checks done first?
o Is the top and bottom axial-correction within 0,05 mm?
o Is the top and bottom radial-correction within 0,05 mm?
o Is axial-side adjustment within 0,05 mm?
o Is radial-side adjustment within 0,05 mm?
o Have the side-adjusting screws been backed off upon completion?
HAVE YOUR COURSE CONTROLLER OR SUPERVISOR CHECK YOUR WORK TO CONCLUDE THIS
MODULE.
YES
NO
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MECHANICAL COUPLINGS & (Law for All South Africa)

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