Alignment Flashcards
What is another term for Offset Misalignement?
Parallel Misalignment
What is not a concern when using the cross dialing method of shaft alignment.
Coupling Eccentricity
What is the name of the condition where all the supporting feet of a machine do not equally support the weight of the machine?
Soft Foot
Describe how the dial indicator hand moves when the plunger is pushed inwards?
Clockwise or a plus reading
What are the two misalignment conditions?
Angular and offset.
What is done to correct vertical offset misalignmenet?
Add or remove equal shims on the drive.
What would you use to rough align prior to using a laser for alignment?
Straight edge and feeler gauges.
What is TIR?
Total Indicator Reading
How is vertical angular misalignment corrected?
By placing an unequal amount of shims front and rear.
What is another term for angular misalignment?
Face misalignment
What is the purpose of this equation?
Calculate a shim change.
Which describes runout?
An eccentric condition.
Which is corrected first Horizontal Alignment or Vertical Alignment?
Vertical Alignment.
What is used to adjust Horizontal Alignment?
JackScrews (Alignment Screws)
What is this?
The side bolt is a Jackscrew
What is Rim Misalignment?
The same as Offset Misalignment or Parallel Misalignment
What is one way to test for Softfoot?
Loosen the anchor bolts one at a time and try to slide a feeler gauge underneithe the feet.
What are two types of soft foot?
Angular and Ordinary
What is ordinary softfoot?
The amount of even gap between one foot of a machine and the baseplate or soleplate.
What is Angular Softfoot?
A uneven gap between a machine foot and the baseplate or soleplate
What should the gap between foot and shim pack be?
Less than 0.025mm (0.001”)
What do you have to be mindful of with Steam Turbine shaft alignment?
What do you do to remedy this?
- Thermal Expansion
- Set the Turbine shaft (shaft that will expand) lower than the driven.
What is one method of testing coupling alignment?
Vibration Analysis
What are the Four methods of coupling alignment?
- Rough Alignment using straight edge and feeler gauges
- Rim and Face dialing
- Cross Dialing
- Laser
What are two sub methods of Cross Dialing?
- Graph Method
- Reverse Reading Dialing
How are shims differentiated ?
By square dimension (A, B, C, D) and thickness.
What are Classes A -D dimensions?
How many shims should you use at most per foot?
3
What order should you stack shims idealy?
Thickest on the bottom, second thickest on the top and smallest sandwhiched between then.
You should not be able to ______ shims when bolts are tightened down.
Move
“Always ______ the jackscrews before _____ the hold down blots.
Back off
Tightening
What is TIR
Total Indicator Reading: the total difference in reading from top to bottom. ( 12 o’clock and 6 o’clock )
When doing Vertical or Horizontal TIR what is a must for the mathimatical readings.
The 12 o’clock and 6 o’clock added together must equal 3 o’clock and 9 o’clock sum.
Vertical TIR is 3 o’clock and 9 o’clock sum.
True or False?
False
It is Horizontal TIR
What is Run-out?
What must be done with the TIR value?
- When the dial and shaft are rotated 180 and there is a slight bent in the shaft.
- TIR must be halfed to get the runout.
Do you check Runout for Rim and Face?
Yes
How do you check for Indicator Sag?
Start the dial on at the 6 o’clock position then zero it. Then rotate it to 12 o’clock position. If the value is positive divide by 2 and that is your dial sag.
What do dial sag corrections only apply to?
Rim readings
What are two types of Runout?
Eccentric and Angular
What kind of runout is this?
Eccentric Runout
What kind of Runout is this?
Angular Runout
What is the equation for calculating shim correction with Angular Misalignment in the vertical dimension.
A/D x Feeler Calculation = Back Shim Change
B/D x Feeler Calculation = Front Shim Change
A and B are measured from center of the hold down bolt to the face.
What kind of alignment is this?
Correcting for Horizontal Misalignment
When do you use Rim and Face Alignment?
When Rough Alignment is not accurate enough.
When can you not use Rim and Face Alignment?
When there is Axial Float of shafts and it can’t be stablized.
What type of Alignment method is this?
Coupled Rim and Face Alignment
What kind of Alignment method is this?
Uncouple Rim and Face Alignment
What is an Advantage with Rim and Face Alignment?
Can be used on large diameter shafts where only one shaft rotates.
What are the limitations with Rim and Face Alignment?
- Errors may occur due to eccentricity of the coupling or shaft.
- If used on shafts with friction bearings in either driver or driven machinery, the end-float that may be difficult to stablize.
What is this called and what is it used for?
A wiggler. Used to enable face readings.
When calculating Face Misalignment what diameter do you use?
The diameter of the total change in position of the wriggler end. From 12 o’clock to 6 o’clock.
Which do you do first in Alignment Horizontal or Vertical?
Vertical
Which do you do first in Alignment Angular or Offset?
Angular
What is the order of Misalignment correction?
(VA) Vertical Angular Alignment
(VO) Vertical Offset Alignment
(HA) Horizontal Angular Alignment
(HO) Horizontal Offset Alginment
Where are the datums taken for Rim calculations?
L1: From the center of both front driver feet
L2 : From the center of both back driver feet
What do you use this calculation for?
For Rim and Face Reading from the Driver Side and Uncoupled Shim Calculations
When the Rim and Face dials are set up from the driver side and reading the driven coupling rim and inside face a positive means what?
What does a Negative mean?
- Insert Shim
- Remove Shim
When the Rim and Face dials are set up from the driven side and reading the driver coupling rim and outside face a positive means what?
What does a Negative mena?
- Remove Shims
- Insert Shims
What type of Alignment method is this?
Cross Dialing Reverse Reading Alignment
What must you do before a Cross Dial Alignment?
Rough Alignment
What is a dial indicator Becket?
The support found behind the dial head connected to the magnetic base.
What type of Alignment is this?
What is used with it?
- Cross Dial Gragh Alignment
- A gragh
What does Axial float specifically affect in Alignment?
Face Alignment
Why is Cross Dialling not affected by axial float.
It does not require Face dials
What are the benefits of Cross Dialling Misalignment?
- Axial Float does not affect the alignment process.
- Coupling Eccentricity does not affect alignment process. Both shaft rotate at the same time.
- Greater Accuracy
- Couplings dont need dismantaling for alignment.
Do both shafts need to be rotated with Cross Dialling Alignment?
Yes
At what length do Cross Dials lose accuracy.
Anything less than 4 inches.
What is the first step for Cross Dial Alignment?
Set both dial indicators to the pre-determined sag plus values.
Where is Sag correction for alignment not nessesary?
Horizontal Readings
What pattern do you use for tightening/torquing down hold down bolts?
X pattern
How many Dowels should be used for alignment maintainment during operation?
2 for each machine which should be as far apart as possible (diagonally).
Does heat affect Laser Alignment?
Yes, it affects the lasers accuracy.
Does Laser Alignment avoid problems with Bar Sag?
Yes
What is a Class 1 laser for alignment?
What is a Class 2 laser for alignment?
- Invisible
- Visible
What is this Equation used for?
What is A?
What is B?
What is C?
Calculating corrections for Cross Dial Reverse Misalignment .
- A = Distance between contact points of Dial indicators
- B = Distance from dial indicator on driven component to the center of the front hold hole of driver unit.
- C = distance from the dial indicator set on the driven unit to the center of the back hold down holes of the driver unit
What is this set up for?
Cross Dialling Graph Alignment.
For Cross Dialling Reverse Reading what does a plus mean for calculating shim change?
What about a minus?
Insert Shims (vertical movement) and push the driver leg towards the 9 o’clock position (horizontal movement).
Remove shims (VM) and push the driver leg towards 3 o’clock (HM).
Are the dials for Reverse Cross Dialling on the same plane or opposite?
Same