Alignment Flashcards
What does alignment refer to?
Lining up two machines that are to be coupled to each other
What does collinearity mean?
Straight line
Which is the “power source” the driven or the driver
Driver
Define misalignment
When two or more shaft rotational centrelines are not collinear under normal operating conditions
What are the three types of misalignment?
Offset (parallel)
Angular
Combination
What does offset refer to?
Parallel misalignment
What type of misalignment is this?
Offset
What type of misalignment is this?
Angular
What type of misalignment is this?
Combination
What are the 4 components of misalignment?
Vertical angular misalignment
Vertical offset (parallel) misalignment
Horizontal angular misalignment
Horizontal offset (parallel) misalignment
How do you typically correct vertical misalignment?
By adding or removing shims Uber the machines feet (typically driver)
What does DBSE stand for?
Distance between shafts ends
What are the 3 basic types of couplings?
Rigid
Flexible
Special
What is pipe strain?
A condition where piping fastened to a piece of equipment stresses the housing
What is soft foot?
A situation where the weight distribution of a machine is not equal on all supports
What type of soft foot is pictured?
Parallel
What type of soft foot is pictured?
Angular heel touching
What type of soft foot is pictured?
Angular Toe touching
What is another name for a base?
Soleplate
What methods can be used to find soft foot?
Dial
Feeler gauge
How do you check for soft foot using a dial?
-Mount dial on MTBM (machine to be moved)
-Place dial on fixed machine coupler at 12 position zeroed
-loosen and retighten each foot (one at a time) observing dial
When checking for soft foot with a dial on the coupling what does a positive reading mean?
Rear foot lift
When checking for soft foot with a dial on the coupling what does a negative reading mean?
Front foot lift
What are the two types of shims to correct angular soft foot
Stepped shims
Elastomer shims
What is the most accurate way of measuring soft foot with feeler gauges?
Check all 4 corners of the foot
When does runout NOT affect the ability to preform an alignment?
When rotating both shafts together
What are the two basic types of runout?
Eccentric
Angular
Which type of runout is pictured?
Eccentric
Which type of runout is pictured?
Angular
What type of alignment allows you to rotate only one coupling half?
Rim and face
Why would a machine with proper alignment still produce vibration?
Imbalance from runout
What is end float?
When a shaft moves axially
What does end float do to face readings?
Causes them to be unreliable
What is dial bar sag? (DBS)
Affects of gravity on the dial bar
What does bar sag affect?
Rim readings only
What reading(s) should bar sag value be added to?
6 o clock rim reading ONLY
What is the method for performing a rough alignment?
Straight edge and feeler gauge or taper gauge
What is the travel on a typical dial indicator?
0.100 inches
What are the 3 methods for measuring angular offset?
Feeler/taper gauges
Internal calipers
External calipers
How is angular offset adjusted?
By shimming either front OR rear feet
How do you determine the position of the dial readings?
By simulating you are standing behind the moveable machine (typically motor) looking at the fixed machine
What are the 4 positions for dial readings?
12 , 3 , 6 , 9
How should the plunger be oriented on a dial when placed?
Half depressed
How do you validate a dial setup?
Sweep reading
What is a sweep reading?
Rotating the dial 360 degrees recording the readings every 90 degrees
What is dial balancing?
Ensuring dial validity is accurate
The sun of the values at 12 and 6 not including dial bar sag should roughly equal 3 and 9
What is DBS?
Dial Bar Sag
What is TIR?
Total indicator reading
What is total indicated reading?
The amount of change a dial has registered
What does it mean If you generate a positive number from your rim and face alignment calculations
You are required to move down toward your datum point
What does it mean If you generate a negative number from your rim and face alignment calculations
You need to move mils away from datum
What should be done first vertical or horizontal alignment?
Vertical
What is bolt bound?
When hold down bolts do not allow sufficient horizontal movement
What should always be your last step in alignment?
Horizontal
What is a live move alignment?
No calculations just using dials. Typically quicker however requires multiple moves
How do you calculate true angularity alignment tolerance
Total indicator reading of the face divided by diameter
TIRface/D
How do you calculate true offset alignment tolerance?
Distance divided by diameter times total indicator reading face minus (total indicator reading rim divided by 2)
X/D X TIRface - (TIRrim/2)
What is a bezel?
The face of a dial indicator
What is validity rule?
Dial sweep readings
3 + 9 = 12 + 6
Means of checking your dial or finding a missing reading
Does not include Dial Bar Sag
What is a sweep indicator reading?
Taking a full reading of a shaft with a dial typically recording 4 points at 90 degrees apart
When mounting a dial how should the dial be placed?
Centred and with the plunger depressed halfway
What are the 4 recognized methods for coupling alignment?
Rough alignment
Rim and face
Cross dialling
Laser
What are the 4 classes of pre cut shims?
A , B , C , D
What is the size of a class C shim?
4x4
What is the size of a class A shim?
2x2
How should multiple shims be placed under a machines foot?
Largest on the bottom
Smallest sandwiched in between 2
What’s the ideal max amount of shims you should use?
3 or less
Why should you always back off the jackscrews before tightening the hold down bolts?
To prevent breaking them
What does the gauge on a dial indicator read in the plunger is depressed?
Positive reading
What does a dial indicator read if the plunger extends?
A negative reading
What does adding the sag value do and where would we do this?
Makes up for the dial bar sag
Only add DBS at the 6 o clock position
What does mils mean?
Thousandths
During rim reading on the DRIVEN coupling you preform your calculation for corrections (shim changes) the end number is positive what do you do?
Remove equal shim amounts from ALL driver feet
During rim reading on the DRIVER coupling you preform your calculation for corrections (shim changes) the end number is positive what do you do?
Insert equal shim amounts to ALL driver feet
What is TPS
Total position sensing
How do you preform TPS (total position sensing)
Live moves using the dial indicator to get your points to zero typically horizontal
What is the goal when conducting an alignment?
Have shafts share the same rotational axis
Which machine do you typically and ideally stand behind to reference your sweep position?
The moveable machine
Angular alignments are measured by placing dial indicator on which part on the coupling?
Face
What does TIR stand for?
Total indicator reading
How can you ensure the machine stays aligned after an alignment?
Monitor and maintain the proper hold down bolt torque
In which position would you look for bar sag during a rim and face alignment?
Vertical offset alignment
How is dial bar sag measured?
A bar sag jig set up with the indicators and a brackets are used
When installing shims what is the maximum recommended numbers to use?
4
What are you correcting when moving the motor sideways using a half turn of each Jack screw against the feet?
Horizontal offset misalignment
How much can hold down bolts be necked down to solve bolt bound?
To the minor diameter of the thread
What are tapered (or layered) shims used to correct?
Angular soft foot
In a typical misalignment what is the most common type of misalignment?
Combination
What measuring device is used to check the thickness of a shim?
Micrometer
Is pipe strain caused by misalignment?
No
When aligning new machinery, why must modifications such as drilling, grinding or enlarging holes not be made to the supplied machine base plate or the machine feet?
It may void the manufactures warranty
What term describes the situation where the hold down bolts do not allow sufficient horizontal movement?
Bolt bound
What does MTBM stand for?
Machine to be moved
What will result if a dial indicator is touching the backside of the coupling face instead of the insides?
Only the positive or negative of the face measurement will change
Where is the thickest shim inserted when placing more than one shim under a hold down bolt
Bottom
If a part moves away from the dial indicator which direction will the dial needle move?
Negative direction
When end play is detected how must it be controlled?
Keeping constant pressure axially on the shaft while measuring
In the rim and face alignment formula what does D stand for
The diameter of the circle the face dial makes
How should a dial indicator be placed on the machinery?
Plunger depressed about mid range
Why would we purposely misalign a coupling when preforming an alignment?
To allow for thermal growth
