1.Kingdom of Saudi Arabia Saline Water Conversion Corporation General Directorate Of Training Programs Training Center JUBAIL S.MARIMUTHU. GEN.MECHANICAL TECHNICIAN. SWCC. YANBU PLANT ID.402667 MAINTENANCE DEPARTMENT ME C H A N I C A L A D V A N C E D C O U R S E MACHINEALIGHNMENT " Course Code:23209 Version 1.0 Prepared by: Fawaz Alghamdi Date:J AN 2005

2. SWCC TRAINING CENTER AL-JUBAIL MECHANICAL MAINTENANCE COURSE MACHINERY ALIGNMENT LESSON No. 1. SUBJECT/TOPIC : MISALIGNMENTAND ALIGNMENT TIME : hours OBJECTIVE : At the end of this lesson the trainee will be able to demonstrate and understanding of Misalignment and Alignment. LOCATION : Al-Jubail Training Center TRAINING AIDS : Overhead projector, transparencies, white board. REF.MANUALS : NUS Training Manual HAND-OUTS : Trainees Manual LESSON OUTLINE : 1. Introduction. 2. Identifying Misalignment. 3. Shaft Alignment using a Straight Edge. 4. Wedge Gauge. 3. SWCC TRAINING CENTER AL-JUBAIL MECHANICAL MAINTENANCE COURSE MACHINERY ALIGNMENT LESSON No. 2. SUBJECT/TOPIC : HEAT AND ITS EFFECT ON ALIGNMENT TIME : hours OBJECTIVE : At the end of this lesson the trainee will be able to describe the effect of Heat on Alignment without error. LOCATION : Al-Jubail Training Center TRAINING AIDS : Overhead projector, transparencies, chalkboard, chalk. REF.MANUALS : NUS Training Manual HAND-OUTS : Trainees Manual LESSON OUTLINE : 1. Introduction. 6. Dowel Pins. 2. Preparations. 7. Aligning Belt Driven Machinery. 3. Run-Out. 8. Tension Setting. 4. Correcting vertical Misalignment. 9. End Float. 5. Correcting Horizontal Misalignment. 4. SWCC TRAINING CENTER AL-JUBAIL MECHANICAL MAINTENANCE COURSE MACHINERY ALIGNMENT LESSON No.3. SUBJECT/TOPIC : ALIGNMENT BY RIM AND FACE METHOD TIME : hours OBJECTIVE : At the end of this lesson the trainee will be able to provdes information in simple way to accomplish the alignment . LOCATION : Al-Jubail Training Center TRAINING AIDS : Overhead projector, transparencies, White board, Marker. REF.MANUALS : NUS Training Manual HAND-OUTS : Trainees Manual LESSON OUTLINE : Detailed procedure by calculation and graph 5. SWCC TRAINING CENTER AL-JUBAIL MECHANICAL MAINTENANCE COURSE MACHINERY ALIGNMENT LESSON No.4 SUBJECT/TOPIC : REVERSE INDICATOR METHOD. TIME : hours OBJECTIVE : At the end of this lesson the trainee will be able to provides information in simple way to accomplish the alignment by reverse indicator method both by forula and graph. LOCATION : Al-Jubail Training Center TRAINING AIDS : Overhead projector, transparencies, White board, Marker. REF.MANUALS : NUS Training Manual HAND-OUTS : Trainees Manual LESSON OUTLINE : 1- Introduction . 2- Procedure applied 3- Formula and graph detailed procedure 6. SWCC TRAINING CENTER AL-JUBAIL MECHANICAL MAINTENANCE COURSE MACHINERY ALIGNMENT LESSON No. 5 SUBJECT/TOPIC : REVERSE MISALIGNMENT METHOD WITH THERMAL GROWTH ALLOWANCES AND TEMPERATURE GROWTH FACTORS. TIME : hours OBJECTIVE : At the end of this lesson the trainee will be able to Perform Alignment by reverse indicator method taking into account different thermal position or growth factor calculation . LOCATION : Al-Jubail Training Center TRAINING AIDS : Overhead projector, transparencies, White board REF.MANUALS : NUS Training Manual HAND-OUTS : Trainees Manual LESSON OUTLINE : 1. Reverse Alignment method. 2. Calculating the adjustments. 3. Aligment language and symbols. 4. Alignment movements. 7. SWCC TRAINING CENTER AL-JUBAIL MECHANICAL MAINTENANCE COURSE MACHINERY ALIGNMENT LESSON No. 6. SUBJECT/TOPIC : VERTICAL PUMPALIGNMENT TIME : hours OBJECTIVE : At the end of this lesson the trainee will be able to understand the basic concept and procedure of vertical pump alignment. LOCATION : Al-Jubail Training Center TRAINING AIDS : Overhead projector, transparencies, Whiteboard,. REF.MANUALS : NUS Training Manual HAND-OUTS : Trainees Manual LESSON OUTLINE : 1. Important fundament points for vertical alignment. 8. SWCC TRAINING CENTER AL-JUBAIL MACHINE ALIGNMENT MODULE HOURS LES SUBJECT/TOPIC No THEORY PRACT TOTAL HOURS HOURS HOURS ALIGNMENT BASICS PART 1 a. Introduction 1. b. Identifying misalignment c. Shaft alignment using straight edge d. Wedge gauge 5 5 10 ALIGNMENT BASICS PART2 a. Misalignment. b. Factor affecting 2. c. Alignment Tolerance d. Misalignment Detection e. Types of Alignment f. Alignment Record. 5 5 10 3. ALIGNMENT BY RIM AND FACE METHOD 5 5 10 REVERSE INDICATOR METHOD 4. 2 3 5 REVERSE ALIGNMENT METHOD WITH THERMAL 5. GROWTH ALLOWANCES AND TEMPERATURE GROWTH FACTORS 2 3 5 5. VERTICAL PUMP ALIGNMENT 5 5 10 TOTAL HOURS FOR HEAT EXCHANGERS 24 26 50 9. MACHINE ALIGHMENT ALIGNMENT BASICS PART 1 LESSON 1 ALIGNMENT BASICS PART 1 LECTURE Objectives To understand the basic of alignment particularly the importance of alignment and understanding of different factors which woodheap to make alignment a best possible way. 1.0 ALIGNMENT THEORY Misalignment is one of the most common faults found in rotating equipment. Understanding how to properly diagnosis and correct for misalignment in plant equipment and how to deal with common pitfalls while out in the field is essential in doing the job right the first time. The alignment of shaft centerlines on coupled machines is one of the most important aspects of machine installation. Contrary to popular opinion, flexible couplings will not always compensate for even moderate amounts of shaft misalignment. Misalignment is any condition in which the shaft centerlines are not in a straight line during operation. Misalignment generates unnecessary forces. Precision alignment removes these forces resulting and cyclic forces resulting in reduced vibration and noise levels, minimized shaft bending and cyclic fatigue reduced energy costs, and increased bearing, seal, and coupling life. Shaft centerline misalignment can be classified as either angular or offset (also called parallel). Angular misalignment occurs when the shaft centerlines meet at an angle. Offset misalignment occurs when the shafts are parallel, but offset from each other. The misalignment may be vertical, horizontal, or a combination of the two. Most shaft misalignment is a combination of both angular and offset misalignment. graphically illustrates the alignment types. Another type of misalignment not associated with couplings is bearing misalignment. the centerlines of two coupled shafts can be properly aligned, but the bearings on one side of the coupling may be misaligned. Bearings can be misaligned if they are not mounted in the same plane; if they are cocked relative to the shaft; or because of machine distortion due to soft foot, an uneven base, or thermal growth. Lesson 1 Page 1 10. MACHINE ALIGHMENT ALIGNMENT BASICS PART 1 2.0 ECONOMICS OF MISALIGNMENT There are a number of cost benefits of precision alignment. It can help reduce plant operating costs by reducing energy costs. Precision alignment also results in increased maintenance savings through reduced parts consumption and reduced overtime. Finally, it can help decrease equipment downtime and increase product quality. A recent study performed at the University of Tennessee found that even small amounts of misalignment could significantly reduce bearing life. The study found that if, on average, a motor was offset misaligned by 10% of the coupling manufacturers allowable offset, there was a corresponding 10% reduction in inboard bearing life. Furthermore, if a motor was offset misaligned by 70% of the coupling manufacturers allowable offset, there was a corresponding 50% reduction in inboard bearing life (Hines et al). the results of the table at the top of this page. 3.0 ALIGNMENT TOLERANCES Alignment tolerances have often been treated with a halfhearted just get it close attitude. But, alignment tolerances are actually the measurement of a job well done and they provide the definition of what close actually is. There are two reasons to use tolerances. The key reason is to establish goals. If you know when the job is finished. If there is not a goal, there cannot be a quality alignment. Lesson 1 Page 2 11. MACHINE ALIGHMENT ALIGNMENT BASICS PART 1 The second purpose of alignment tolerances is to establish accountability. Accountability is the evaluation of alignment quality. If there is no tolerance to compare an alignment to, how can the quality to the alignment be judged? Accountability can create competition, driving a mechanic to get the job done better. Misalignment is one of the most common faults found in rotating equipment. Because of the frequency of occurrence, machines are often aligned with out taking the time to properly diagnose the machine fault. Diagnosing misalignment in a machine can be difficult because the vibration, phase, and temperature characteristics are dependent. On the type of coupling used. Misalignment leads to reduced bearing, seal and coupling life. Precision alignment reduces plant operating costs through reduced maintenance and energy costs as well as reduced equipment downtime. Asset optimization is possible with a balance of Technology, Expertise, and Work Processes. In theory, machine alignment is a very straightforward process. With some type of measuring device extended across the coupling, the shafts are rotated to several positions (at least three) to determine the relative position between them. Since alignment is a iterative process (meaning that the misalignment should continuously decrease with each machine move), it is theoretically only a matter of sufficiently repeating alignment corrections until an acceptable solution is achieved. In fact, quality alignment is not dependent on the type of measurement system used. Any good dial indicator set or laser system should be sufficient to perform quality alignments. Therefore, in heavy industrial applications, where the cost of downtown can be in excess of $ 10,000 per hour, the fundamental question for an alignment program is not simply Can I successfully align the machine? but rather fastest alignment solution so that I can start production again? Furthermore, since misalignment is often compounded by structural faults such as soft fool, piping strain, induced frame distortion, excessive bearing clearance, shaft rub, etc., it may not be possible to align the machine without first addressing these additional problems. These pitfalls can turn an otherwise simple alignment job into an all day affair frequently with unsatisfactory result despite conscientious effort and a considerable investment in manpower and downtime. Lesson 1 Page 3 12. MACHINE ALIGHMENT ALIGNMENT BASICS PART 1 For this reason, it is crucial for the personnel performing alignments to be aware of the kinds of structural faults that can complicate the alignment process and that they learn to recognize the tell tale signs of bad measurements before they invest valuable downtime in an unproductive exercise. 4.0 COLLECTING VALID DATA Some fairly simple yet powerful techniques can be applied to determine the validity of alignment readings before investing time executing a machine move that may be wrong. If using a dial indicator set, it is useful to apply the data validity rule to each set of readings. The data validity rule compares the readings taken at the four cardinal positions: Top + Bottom = Left + Right. It provides a quick way to determine the validity of an alignment solution before moving the machine. This simple check is able to catch many set up errors and mechanical faults such as: Loose brackets. Sticking indicators. Indicators set too high or too low. Improperly recorded data values and / or signs. Sleeve bearing float. Surface irregularities or eccentricities. Excessive bearing clearance. Small deviations from the validity rule are to be expected. If the difference is more than 10%, it is possible that the coupling may be loose enough to provide excess torsional play (backlash). To reduce the coupling engaged while rotating the shafts from the driven machine in the normal direction of rotation. If the error is greater that 20% the cause should be determined. This could be a problem with the alignment fixture(s) or a concern with the machine being aligned. Alignment problems occur from loose fixtures or improper use of fixtures. Possible machine concerns include locked couplings, spalled bearings, machine binds, etc. If the data validity rule is not checked when such a problem exists, these potential machine faults will remain undetected and substantially complicate the alignment process. Even worse, the objective of increasing machine reliability through quality alignment will not be accomplished. When using a laser alignment system, the potential for user error is greatly reduced de to the automatic measurement and recording of readings. However, the data validity rule can still be very useful to indentify structural faults such as excessive Lesson 1 Page 4 13. MACHINE ALIGHMENT ALIGNMENT BASICS PART 1 bearing clearance and other forms of structural looseness. To apply the validity rule with a laser system, it is necessary to record all four cardinal readings (top, bottom, left, right) and plug them into the formula. If, however, the alignment solution is based on only three of the four cardinal readings, the user will not have the ability to check the validity of the solution. In one such example involving a feed water pump in a power plant, an alignment was attempted using only three of the four cardinal measurement (top, left, and right the bottom reading was omitted). The machine was moved as indicated by the laser system but on improvement in the alignment condition was achieved. Numerous readings and machine moves were implemented but failed to result in any improvement in the alignment condition. When the reading for the fourth position (on the bottom) was manually collected and the values were plugged into the equation, it was clear that the validity rule was being violated. Visual inspection of the machine train indicated that one of the feet on the gearbox had been bolted down with the wrong size bolt head thereby substantially reducing the hold down force at this foot. This allowed the foot to lift slightly during shaft rotation creating substantial error in the readings. After replacing it with the proper size bolt, the operator was able to align the machine in just a few moves. (Note: more advanced system are currently available that will automatically apply the validity rule to the obtained readings and indicate whether acceptable levels for deviation have been exceeded.) It is important to realize that otherwise straight forward alignment jobs can become highly complex and yield unacceptable results if the technician does not address the quality of the alignment measurement and potential frame stress conditions (frame distortion, soft foot, and piping strain) during the pre alignment check. These steps should all be conducted before the technician ever begings to move the machine. 5.0 MOVING THE MACHINE Every machine is considered moveable, even those with rigid piping attached. Some machines are more easily moved than others. The aligner has the option to move one or the other, or both machines. Machines shall be adjusted with small, precise movements. Excessive force, that could cause internal or external damage, is to be avoided. Steel-hammer blows on bare steel or iron Lesson 1 Page 5 14. MACHINE ALIGHMENT ALIGNMENT BASICS PART 1 machine housings are unacceptable. Hammering on wooden blocks is OK. Jackscrews are the preferred movement method. Horizontal movements shall be monitored with dial indicators, or other measuring instruments, to know when to stop. "Bolt bound" conditions can be handled in various ways, depending on the situation at the job site. The following methods are allowable: 1. Moving both machines 2. Undercutting the bolt diameter to remove threads 3. Reducing bolt size one nominal fractional size (i.e., 3/4 bolts to 5/8 bolts is OK) 4. Enlarging the hole is OK if structural integrity is not compromised 5. Tilting the machine with differential shimming After all movement is done, the machines will be secured by tightening the holddown bolts to the recommended torque in accordance with the manufacturers instructions. If no instructions are available, the torque values in Appendix D shall be used. After torquing the holddown bolts, a final set of shaft-to-shaft readings will be taken and reported as the final orientation. Doweling of machines in place will not be done unless the installation instructions specifically require it. 6.0 UNDERSTANDING DIAL INDICATOR A positive reading indicates that the plunger is pushed inward and the dial rotates in a clockwise manner, thus indicating a positive reading. A negative reading indicates that the plunger is extended outwardly and the dial rotates in a counter clockwise manner indicating a negative reading. Dial indicators have many different face designs and maximum indicator travel. It is important to become familiar with the dial indicators and other measuring devices that you are going to use. For the case where a dial indicator is mounted on the driven equipment and the plunger touches a surface on the driving Lesson 1 Page 6 15. MACHINE ALIGHMENT ALIGNMENT BASICS PART 1 equipment. A positive value of the difference between the top and bottom readings would indicate that the plunger is depressed greater at the top, thus the axis of the driving equipment (indicator plunger contacts this equipment) is higher than the driven equipment. 6.1 OTHER HELPFUL HINTS WHEN USING A DIAL INDICATOR Adjust indicator face to zero. Rotate shaft one complete revolution and note the maximum positive or negative value. Return the shaft to location of maximum value and readjust face to zero. Rough align equipment to ensure that equipment to ensure that equipment alignment is within the indicator total travel. Make sure that supporting hardware is reliable and rigid. Areas of attachment should be large enough for indicator supports and clean for mounting 7.0 SHIMS MATERIAL The best choice for shim material is stainless steel. This material is very stable and is easy to maintain. Carbon steels should be avoided because it will rust and eventually compromise the machinery alignment. Synthetic or plastic shim material should be avoided for industrial applications because it is easily damaged and under heavy load will deform which compromises the alignment condition. The shims used for industrial applications should be large enough to adequately support each foot. Commercial shims are available in various dimensions. These shims are precut and dimensioned to standard thicknesses which are labeled on a small tab. These shims are easy to install and are difficult to mix up. If shims are manufactured in the field they should be large enough to support the machine foot and all edges should be smoothed to eliminate burrs. Kinked or otherwise damaged shims should be discarded and new ones obtained. The shims, the base plate surface, and bottoms of the machine feet should be clean and free of defects prior to installing any shims. 8.0 WHICH MACHINE MOVES? Generally, the stationary machine has certain constraints which make it impractical to move it. Pumps have rigid piping attached, generators have complex cooling systems, and gear boxes are Lesson 1 Page 7 16. MACHINE ALIGHMENT ALIGNMENT BASICS PART 1 relatively sensitive to any orientation other that flat and level. When these machine types are moved the attached systems must be relocated to eliminate sources of strain. Multiple case machine trains, such as dual compressors driven by one turbine, pose another problem. All three machine shafts must operate co-linearly to function efficiently. By studying the graphical plot of the current alignment and the desired alignment it may prove most effective to move the center machine case, instead of moving two or three machines. Energy is continuously added to increase the fluid velocities within the machine to values in excess of the occurring at the discharge such that subsequent velocity reduction within or beyond the pump produces a pressure increase. The categories of that pump are include all kinds of centrifugal pumps and air lift pump and in lesson two they define in detail. Lesson 1 Page 8 17. MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 LESSON 2 LECTURE ALIGNMENT BASICS PART2 Objectives This lesson further explains the importance of alignment by mentioning different damages which misalignment caures and important preliminary to accomplish the 1.0 MISALIGNMENT EFFECTS 1.1 EFFECT ON COUPLING The most affected part of a unit that suffers from misalignment is the coupling. Regardless of the type employed on a unit, either rigid or flexible, the coupling does not compensate for gross permanent misalignment. Some people are of the opinion that since the coupling is termed flexible it requires less accurate alignment. This is not so. This type of coupling provides allowances only for unintentional, unexpected, but ever present short periods of misalignment created by the inherent characteristics of the units operation. It is because these flexible couplings are designed to accommodate these forces that they do not fail as readily as bearings or seals, which are not designed for any great amount of misalignment. 1.2 EFFECT ON BEARING, SEALS AND SHAFTS Stresses that accompany misalignment also have a severe effect upon bearings, both antifriction and plain, thereby reducing their life. Proper alignment cannot extend the natural life of an antifriction bearing. Misalignment can certainly reduce their natural life. When the life of a bearing is determined, it is done without misalignment forces being present. 1.3 SHAFT AND OTHER PARTS Most mechanical seals are designed to function properly only when minimum shaft deflection is encountered, thus, mechanical seals fail due to shaft deflection created by misalignment. Unlike other mechanical problems which begin as a minor deficiency and grow into something quite noticeable and major, misalignment is Lesson 2 Page 1 18. MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 as severe the first revolution as it is when the machine finally fails. This is the case when a machine does not shift due to misalignment forces. It is through this minor deficiency that the major failure can stem. It is true that stresses from misalignment are in direct proportion to the speed of the unit, with the amount of initial misalignment remaining constant. Speed of unit should generally dictate the tolerances allowed for alignment. Operating characteristics will also govern initial and operating alignment tolerances. The following discussion of shaft alignment is dependent on keeping these thoughts of mind. 2.0 FACTOR AFFECTING ON ALIGNMENT Prior to discussing the particular procedure to be employed on a given unit, there are several factors that may mechanics either dont understand or fail to consider.. 2.1 PIPING STRAIN Practically all manufactures assembled units, both driver and driven on a common base are factory alignment. This factory alignment only serves the factory purpose to determine if and how the unit can be alignment within its mechanical limits. Factory alignment was supposedly obtained with the base in an absolutely level, unstressed position, but when the unit grant and piping installed on it many undue stresses are involved to disturbed the alignment. For achieving the maximum possible factory aligned mechanical limit the unit must be grout in a level foundation after that stage take a preliminary alignment reading and record it. Install all piping on the pump and electrical connection, checked and measure the alignment distortion. This will allow noting any movement of the shafts caused by stresses imposed by the piping . Stress relieving or some other means of eliminating these stresses may have to be performed. Additional pipe supports may be required. If blinds have been placed in the lines during shut down, final alignment not be performed until these have been removed. Note: On a installed unit, when pump casing or piping removed for maintenance purpose and at the time of reinstallation the piping strain can again activate. Lesson 2 Page 2 19. MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 2.2 DOWEL PINS AND PUMP CASING JOINTS On some unit dowel pins are provided for exact pump casing joint, because it is very critical to the proper operation of the pump. Manufacturers of these pumps require that this joint be evenly loaded to insure proper operation of that unit. Most pump designs allow a space at this joint. During the assembly of the pump, the mechanic equalizes this space using feeler gages. From this point on in the installation and alignment of the pump, this space should not be disturbed. However, some mechanics unwisely use this adjustable joint to achieve proper alignment. By doing this, there is danger of reducing axial impeller clearance at the tips of the impeller vanes. 2.3 PUMP BEARINGS SUPPORT FIG. 1-1 If this type pump has an adjustable support leg under the inboard bearing, it should not be secured until the case joint clearance has been equalized. Then, with a dial indicator monitor, pull this leg down 1 to 3 mils (.001 - .003). This will insure proper support of that bearing without placing an undue strain on the casing. Fig. 1-1. Pump Bearing Support. Lesson 2 Page 3 20. MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 2.4 SOFT FOOTING All driver support feet must be on the same plane. This condition is extremely important and should be one of the first problem areas to be checked. Drivers with four or more feet are the only ones to possible create this problem. The trade name of that problem is known as Soft Footing . Fig. 1-2 The soft footing created when one foot is slightly higher, or lower in elevation. The soft footing created two major problems. Fig. 1-2. Soft Footing. First exact alignment is very difficult to achieve, because this foot is tightened down with the hold down bolt or nut it must do one of two things it must spring the frame work and come down or it must break the foot. The spring action create different alignment reading and condition of this sort is a big handicap to the person doing the alignment. Secondly, this condition of having a soft foot will introduce undue stress within the unit itself. Bearings, mechanical seals, seals, and wear rings suffer without need. Vibration, parts breakage, and ultimate failure is possible when this condition is not resolved. The shaft no longer runs within a line bored bearing housing, one is displaced in reference to the other. 2.4.1 METHOD FOR ELIMINATE SOFT FOOTING First point for eliminate the soft footing, better used minimum number shims rather than a bulk of small measurement shim because that can create a spongy foot and that will behave as a soft foot. Secondly if that is a permanent problem it must be eliminate by shimming before the alignment. To eliminate the possibility of a soft foot, attach a dial indicator to the support pedestal and set the indicator button on top of one of the support feet. Zero the indicator. Now loosen the support nut and read the indicator. If the indicator is deflected more than 3 mils move to the adjacent foot and take a Lesson 2 Page 4 21. MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 reading in the same manner. If the reading on the second foot exceeds the first reading, the second foot should be shimmed. Repeat this procedure until you obtain an indicator reading of less than 3 (0.003) mils when one foot is loosened and the others are tight. 2.5 MAGNETIC CENTER An electric motor is said to run in its magnetic center. This means that the rotor is pulled into operating position by the magnetic force whenever the motor is running. For this reason the coupling length can not be determined when the machine is at rest unless a mark has been made, showing the running position. If there is no mark the motor must be started to see just where the shaft moves to, while it is running. Then the coupling spool is made up to suit the distance between couplings for operating conditions. Also lock the axial movement of the shaft while aligning, because that axial movement differ the each face reading. 2.6 SHAFT DEFLECTION, COUPLIGN WEAR AND UNEVEN BEARING WEAR The shaft deflection affects the concentricity of the center line and causes of misalignment. The coupling wear in case of that when rotating only one coupling for alignment can affects the parallelism of the two mating halves of coupling and causes misalignment. Uneven bearing wear again affects the concentricity of the shaft center line, the same as in the case of shaft deflection. The above mention factors must be checked before a alignment job started by runout reading. For taking run-out reading the dial magnetic base fixed on the base plate and dial on the coupling OD and set it zero. The shaft is rotated and the indicator observed to see if the permitted amount of deflection is not exceeded. 2.7 HEAT GROWTH (PURPOSE OF HOT CHECK) Lesson 2 Page 5 22. MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 Since there is a temperature change in a unit from the shut down temperature to the running temperature, we can also expect to have a dimensional change caused by this change in temperature. Depending upon the design and service of the unit, this change in dimension will vary in amount and direction. This is why a hot check is vital to proper alignment. As a rule, hot alignment is performed when there is a temperature difference between driver and driven of 150 degrees or more. Here again this is a general rule. Each particular unit will determine how it is to be aligned. Basically there are two concepts about a hot check. One concept is to achieve perfect alignment, unit aligned in cold and then put the unit on stream. Once the operating temperature are reached, the unit is shut down and alignment is again checked. Additional moves are made once the unit is cold again to compensate for hot movement. There are several disadvantages to this method. First is the fact that an additional shim change time will be required. Time consumed for dimensional changes and shut down The second concept of hot alignment is that of knowing where the unit will go. If the facts are not known as to the units movement, it is easy to second guess the units movement, if the facts, or calculations, are correct as to where the unit will move, the unit will align itself. If it does not, at least it will move in the desired direction. One apparent advantage of this concept is that it is possible not be forced into an additional shim changed based upon hot readings. There is one limitation. If cold alignment is drastically off, as in the case with a steam turbine driving a cold service pump, putting the unit on stream should be done slowly and cautiously to allow warm up and positioning of the shafts. Nearly all units are aligned cold with allowances made for expected thermal growth. Regardless of whether these allowances have been made or not, a hot check should be performed. This check will confirm the hot position of the shaft 3.0 ALIGNMENT TOLERANCES Perfect alignment is the desired objection but in the practical field and in many cases the achievement of (0.00) alignment reading is quite difficult and time consuming job. So the alignments for a unit can accept with some tolerances. Remember a stock set of alignment tolerances which are suitable for all of industry just simply does not exist. As key a good alignment tolerances for a given unit is one which permit the unit to run without creating forces great enough to causes Lesson 2 Page 6 23. MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 the components to fail prematurely. According to that view forces generated by misalignment are directly related to the speed of the shafts, it is logical to use speed as the governing agent to establish alignment tolerances. Economics is the other factor for establishing the acceptable tolerances. For example, a pump which requires a new seal every six weeks would hardly warrant the time required to establish perfect alignment. This is especially true when the shafts can be placed within tolerance within a an hour or so. On the other end of the spectrum is a unit which is not planned to come down in two years. The extra time required to achieve perfect alignment is justified. Some people in industry use the vibration caused by misalignment as the criteria for alignment tolerances, but a practical expenses, that a very low tolerances can be double without an appreciable change in the amplitude of vibration. Listed below are some tolerances that are based upon speed and generally accepted in production industries. The slow speed range will encompass the majority of electric and steam driven units. SLOW SPEED 3550 RPM & Below 5 Mils on OD 3 Mils on Face HIGH SPEED 3600 RPM & Above 2 Mils (TIR) on OD 1 Mil (TIR) on Face Flexible coupling manufacturers describe the capabilities of their couplings on the basis of maximum angular misalignment, among other things. This is the amount at which their coupling will still function. Lesson 2 Page 7 24. MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 This can hardly be used as the criteria for establishing alignment tolerances. 4.0 MISALIGNMENT DETECTION It should be noted that misalignment can be detected while the machine is in operation. Forces caused by misalignment will create vibration as mentioned before. The characteristics of this vibration is what can be used to determine a condition of misalignment. It specially is the direction of this force that is the key, a high axial force. A high axial force is generated when the misalignment is primarily angular. This is influenced to a large extent by the type of coupling transmitting the forces. When the type of mis-alignment is primarily OD, or parallel, the axial forces subside and a larger radial force is evident as shown in Fig. 1-3. To determine where the forces are and in what direction they are in is a simple task provided an adequate instrument is available. Fig. 1-3. A is measuring Axially and B is measuring radially vibration for detecting misalignment. The most effective manner to confirm misalignment is with dial indicators. As was mentioned earlier, the alignment of two shafts can Lesson 2 Page 8 25. MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 be well outside the tolerances normally established and still not produce an alarming vibration level. This is due primarily to the type coupling employed and the type of misalignment in the unit. Each type of misalignment has its own characteristics of vibration and dial indicator readings. 5.0 TYPES OF MISALIGNMENT Basically, there are three conditions that may exist for misalignment. As shown in Fig. 1-4, the shaft are parallel to each other but offset somewhat. This condition is known by several terms. 5.1 PARALLEL MISALIGNMENT But more commonly by parallel or, better yet OD. Shaft center lines do not intersect to correct for this condition movement is made for one half the TIR of OD indicator. Fig. 1-4. OD Displacement. 5.2 ANGULAR OR FACE MISALIGNMENT This type of misalignment is represent by Fig. 1-5 should be noted that the shaft center lines intersect at only one point, as opposed to being concentric. Any adjustments to this condition should be made against TIR of face Indicator. Fig. 1-5. Angular or Face Displacement. Lesson 2 Page 9 26. MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 5.3 MISALIGNMENT BY COMBINATION OF ANGULAR & PARALLEL That condition involves a combination of these two condition as shown in Fig. 1-6. Fig. 1-6. Angular Parallel Displacement. In order to make the task of shaft alignment more interesting, we must cope with these conditions in both the horizontal plane, looking at the side of the unit, and in the vertical plane, looking down on the unit. Again, the utopia is to get these shafts on a concentric center line throughout their entire length, or TIR OD of O and TIR FACE of O in both planes during the hot check. Depending upon speed and unit, deviation from the exact alignment can be tolerated. The specific procedure that should be, or better yet can be, used to align the shafts will be governed primarily by the unit. Since there is an unlimited number of different sizes and types of units requiring alignment, lets narrow this down to three categories. Each category is a separate procedure; two indicator, Reverse Indicator, and Dynamic to Static Methods. 6.0 ALIGNMENT RECORDS Regardless of the procedure employed for shaft alignment, a sound set of records should be maintained for each particular unit being aligned. These records not only aid the mechanic during the aligning process, but also serve as permanent record for future alignment. The record shown in Fig. 1-7 was designed for one particular procedure of alignment, the Indicator Reverse Method. With very minor alternations, this same form can be used for each particular procedure discussed in this study. The majority of the form is self- explanatory. However, on each procedure the reference of direction is Lesson 2 Page 10 27. MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 essential. This form provides for the location of North. Any direction is suitable but North is generally used. Direction will prove to be of great value when determining lateral shifts. Inside the circles are located a portion of an arrow. It should be completed to show the direction of rotation of the unit, which is also the direction the shafts were turned to obtain Indicator readings. Fig. 1-7. Alignment Record Sheet. Lesson 2 Page 11 28. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD LESSON 3 LECTURE ALIGNMENT BY RIM AND FACE METHOD DETAILED PROCEDURE BY CALCULATION AND GRAPH Objectives This lesson provides information in simple way to accomplish the alignment by rim and face method by formula and graph. You can use the Rim & Face Method to perform a calculated precision alignment process. You may use a variety of shaft alignment fixtures. We recommend that you use a commercial package designed to accommodate a variety of shaft diameters. The fixtures should include an assortment of rods to span various coupling lengths. These packages expedite the precision alignment process. Also, sag values can be pre-determined for the standard rod assortment. To perform the Rim & Face Method, you must: Mount the dial indicators fixtures. Measure the A, B, & C dimensions. Obtain as-found readings. Determine the vertical foot positions. Make vertical corrections. Make horizontal corrections. Re-measure and record final alignment values. 1.0 UNTING THE DIAL INDICATOR FIXTURES 1. To mount the fixtures follow these steps: 2. With the coupling broken, mount the fixture to the stationary shaft or coupling hub. 3. Span the coupling with a rod. 4. Rotate the fixture to 12:00. 5. Attach the face dial indicator. The dial indicator plunger must be centered for equal positive and negative travel. 6. Attach the rim dial indicator. The dial indicator plunger must be centered for equal positive and negative travel. 2.0 FIXTURE MOUNTING PRECAUTIONS Lesson 3 Page 1 29. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD Regardless of the specific hardware being used, the following precautions should be observed. Never attach the fixture to the flexible portion of the coupling. Maximize the sweep distance of the face dial indicator for the geometry of the machine being aligned. If the face dial contacts the coupling facedirectly, ensure the plunger of indicator contacts the coupling near its outer edge. Ensure fixtures are mounted at a position where rotation is possible. It is desirable to have 360 degrees of rotation. Before obtaining alignment measurements, determine dial indicator bar sag of the rim dial indicator and ensure dial indicator readings are valid and repeatable. Fig1 1 The A Dimension is the diameter of face indicator travel. The A Dimension should be slightly less than the coupling diameter. This is the most critical dimension. Measure A very carefully. Lesson 3 Page 2 30. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD 2. The B Dimension is the distance from the rim indicator to the front foot bolt center. This dimension is measured parallel to the shaft. 3. The C Dimension is the distance between front and rear foot bolt centers. This dimension is measured parallel to the shaft. 3.0 OBTAINING AS-FOUND READINGS To obtain a complete set of as-found readings, perform the steps below: 1. Rotate the dial indicators to 12:00. 2. Set the rim dial indicator to the positive sag value. 3. Set the face dial indicator to zero. 4. Record the setting of both dials at 12:00. 5. Rotate the dial indicators to 3:00. 6. Determine and record the reading on both dials. 7. Rotate the dial indicators to 6:00. 8. Determine and record the reading on both dials. 9. Rotate the dial indicators to 9:00. 10. Determine and record the reading on both dials. 11. Rotate the dials to 12:00 and ensure both dials return to their original setting. Document as-found results using a format similar to that shown below. Fig 2 4.0 MEASURING & INTERPRETING VERTICAL MISALIGNMENT To measure vertical misalignment, perform the following steps: Lesson 3 Page 3 31. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD 1. Rotate the dial indicators to 6:00. Fig 3 2. Set the face dial indicator to read zero. 3. Set the rim dial indicator to the sag value. 4. Rotate both shafts (if possible) to 12:00. Fig 4 5. Record the DIR and DIF dial indicator TIR values. To determine offset and angularity from the 12:00 TIRs, use the following rules: Coupling Offset = Rim Dial (DIR) TIR 2 Shaft Angularity = Face Dial (DIF) TIR A dimension Lesson 3 Page 4 32. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD 5.0 MEASURING & INTERPRETING HORIZONTAL MISALIGNMENT To measure horizontal misalignment, perform the following steps: 1. Rotate the dial indicators to 9:00. Fig 5 2. Set both dial indicators to zero. 3. Rotate both shafts to 3:00. Fig. 6 4. Record the DIF and DIR dial indicator TIR values. To determine offset and angularity from the 3:00 TIRs, use the following rules: Coupling Offset = Rim Dial (DIR) TIR 2 Shaft Angularity = Face Dial (DIF) TIR A dimension Lesson 3 Page 5 33. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD 6.0 CALCULATING THE FRONT AND REAR FEET POSITIONS Front foot position calculation: = ( Face TIR x B) + 1/2 Rim TIR A Rear Foot position calculation: = ( Face TIR x (B+C)) + 1/2 Rim TIR A Positive values mean the foot is high, shims must be removed. Negative values mean the foot is low, shims must be added. 7.0 RIM-FACE CALCULATION PRECAUTIONS 1. Ensure the rim and face dial indicator TIRs are properly determined from the dials prior to performing calculations. 2. Be careful NOT to make mathematical errors when subtracting signed numbers. 3. Observe parentheses in the equations. Perform operations inside parenthesis first. 4. Do NOT make human errors substituting real values into the equations. Lesson 3 Page 6 34. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD 5. Ensure the A, B, and C dimensions are accurate and are properly entered into the equations. 4 8.0 CONSTRUCTING A RIM-FACE GRAPH To construct a scaled Rim-Face graph, perform the following steps: 1. Obtain graph paper with 10 divisions between bold lines. 2. Turn the graph paper so that the long side is horizontal. 3. Draw a horizontal line at the center of the page. This line represents the stationary shaft center and is drawn across the page midway down the graph dividing the page. It is helpful if this line is on top of one of the bold lines. 4. Determine the horizontal plotting scale. Always use the largest scale possible. Measure the distance from the stationary indicator plunger to the center-line of the rear feet of the movable machine. Standard graph paper is about 10 inches across. The largest horizontal scale will be the machine distance divided by the page width. Note your horizontal scale. 5. Make a vertical line on the extreme left of the horizontal line. This mark represents the point where the rim dial indicator contacts the shaft or coupling hub and is labeled: DIR. 6. Make a second vertical line representing the point along the shaft length of the front feet of the movable machine (RF). 7. Make the third vertical line representing the point along the shaft length of the rear feet of the movable machine(RF) Lesson 3 Page 7 35. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD Fig.7 9.0 PLOTTING OFFSETS After setting up the graph, the next step is to plot two offset points. One is the offset measured in the plane of the rim dial indicator (DIR). The other offset point is derived from the face dial indicator (DIF) reading and the A dimension. To plot the offsets, perform the following steps: 1. Determine the vertical scale. The vertical scale is typically 1 mil (0.001) per division. In cases of gross misalignment where the offsets will not fit on the page, a larger scale, such as 2-3 mils per division, is sometimes required. 2. Plot the offset from the rim dial indicator on line DIR. Use the horizontal line representing the stationary shaft centerline as the reference. All points above this horizontal line are positive (+) and all points below the line are negative (-). Ensure you divide the Rim Dial TIR by 2 to obtain an offset value. 3. Plot the second offset point using the shaft slope (Face TIR / A dimension). Lesson 3 Page 8 36. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD Plot this point counting from the DIR offset point! In the rim-face graph example below, the DIR offset is - 10 mils and the shaft slope is + 4 mils over an A dimension of 5. Fig.8 10.0 DETERMINING MOVABLE SHAFT POSITION After plotting the two points, to determine the movable shaft position perform the following steps: 1. Using a ruler or straightedge, draw a line through the two offset points that extends to the rear feet of the movable machine. 2. Count the number of squares in the plane of the front and rear feet to determine the position and corrections needed. In the example below, the feet of the machine are 2 mils low; shims need to be added. The rear feet are positioned 6 mils too high; shims need to be removed from both rear feet. Lesson 3 Page 9 37. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD Fig.9 11.0 RIM-FACE GRAPHING PRECAUTIONS 1. Ensure proper horizontal and vertical scaling techniques are consistently used. 2. Always double check the position of vertical lines drawn to represent the DIR, FF, and RF. 3. Ensure the two plot points are properly determined from TIRs. 4. Ensure positive offsets are plotted above the horizontal reference line and negative offsets are plotted below the line. 5. When interpreting the graph to determine the movable shafts front and rear feet positions in the vertical plane, observe the following rules: If the movable shaft is above the horizontal stationary shaft reference line the shaft is too high. Lesson 3 Page 10 38. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD If the movable shaft is below the horizontal stationary shaft reference line, the shaft is too low. 6. When interpreting the graph to determine the movable shafts front and rear feet positions in the horizontal plane, view the graph the way you view the machine, that is, standing behind the movable machine facing the stationary machine. Also observe the following rules: If the movable shaft is above the horizontal stationary shaft reference line the shaft is positioned to the right. If the movable shaft is below the horizontal stationary shaft reference line, the shaft is positioned to the left. 12.0 MAKING VERTICAL CORRECTIONS To correct vertical misalignment, follow the steps below: 1. Determine the vertical position of the movable machine using calculation and/or graphing techniques. Positive values at the feet mean that the movable machine is high, therefore you will remove shims. Negative values mean that the movable machine is low, so you will add shims. 2. Make shim changes to both front feet and both rear feet as needed. 3. Always check shim thickness with an outside micrometer. Precut shims aren't always what they're marked; many shim manufacturers designate shims with the nominal thickness. 4. Use consistent and correct torquing procedures. 5. As shim changes are made, check for and take precautions to avoid creating soft foot conditions. Lesson 3 Page 11 39. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD 13.0 MAKING HORIZONTAL CORRECTIONS To correct horizontal misalignment, follow the steps below: 1. Rotate the dial indicators to 9:00 and zero them. 2. Rotate both shafts (if possible) to 3:00. 3. Adjust the dial indicators to one-half values. 4. Move the front feet of the movable machine as you watch the rim indicator move to zero. 5. Move the rear feet of the movable machine as you watch the face indicator move to zero. 6. Repeat steps 4 & 5 until both dial indicators read zero. Fig.10 Lesson 3 Page 12 40. MACHINE ALIGNMENT REVERSE INDICATOR METHOD LESSON 4 LECTURE REVERSE INDICATOR METHOD BY FORMULA AND GRAPHDETAILED PROCEDURE Objectives This lesson provides information in simple way to accomplish the alignment by reverse indicator method both by formula and graph. 1.0 INTRODUCTION The dial indicator reverse method of shaft alignment is the most accurate procedure. By using conventional tools and instrument, achieve a great amount of accuracy in minimum time. In this method two dial indicator are fixed on the both couplings rims, just exactly reverse to each other, and all reading taken on the two coupling rims. As mention in Fig. 4-1. Since the face reading does not involve in this procedure, the thrust and axial float does not affect the reading obtained and that is the major advantage of this procedure. 2.0 WHERE THIS PROCEDURE APPLIED Since this procedure of alignment have many advantages and use of this procedure a is limited only by the characteristics of the unit itself. Here are some advantages and use limits. Considered these as a general. Fig. 4-1. Reverse Indicator Method. Lesson 4 Page 1 41. MACHINE ALIGNMENT REVERSE INDICATOR METHOD 1. This method is preferred when the distance between the adjacent shaft ends greater than one half the coupling diameter. 2. It is preferred especially for large equipment operating at high speed. 3. This method is also preferred when coupling run-out cannot be eliminate. 4. When one or both shafts have end float or have axial movement of the shaft. 5. also preferred, when gear type couplings are used. 6. More over this procedure can be used for all kind of equipment due to its accuracy in a very short time. 3.0 DETAILED STEPS OF PROCEDURE Any procedure that is effective has a definite outline. It was proven in the Two Indicator Method and will be proven in this procedure. Since both are procedures to achieve alignment of two rotating shafts, each has steps that are common to each other. The discussion of the steps in the previous procedure are applicable to this procedure. 3.1 LOCK OUT 3.2 CLEAN FEET & PADS 3.3 DETERMINE INDICATOR SAG & RECORD If using two brackets, check the sag for both brackets list the sag for the driver to driver bracket. 3.4 PROVIDE FOR COUPLING GAP 3.5 ROUGH ALIGN 3.6 ELIMINATE SOFT FOOT 3.7 COMPLETE RECORD SHEET WITH INFORMATION & DIMENSION a) Measured the distance from the bracket to the post and record as mention in Fig. 4 - 2. b) Measure the distance from the center of the bracket to center of the in board feet and record it. c) Measure the distance from the center of the bracket to center of the out board feet and record it Lesson 4 Page 2 42. MACHINE ALIGNMENT REVERSE INDICATOR METHOD 3.8 TAKE A ROUGH ALIGNMENT BY STRAIGHT EDGE AND MINIMIZE THE SIDE TO SIDE DIFFERENCE UP TO THE POSSIBLE LIMITS 3.9 TAKE READINGS a. First of all dial indicators are attached to each half coupling hub using brackets - see Figure 4 -2. The indicator on the stationary machine hub (usually the driven machine) is set to zero at point 1. The indicator on the moveable machine hub (usually the driver) is set to zero at point 2. Points 1 and 2 must be 180 apart. b. Both shafts are turned together clockwise 90 and indicator readings are recorded. This process is repeated until four sets of readings on each hub are recorded. The readings are checked for consistency, and another entire set of readings is taken. If readings are not repeatable, the problem must be found and eliminated in the machinery, the tools, or the method. Equipment I.D. : __________________ Date______________________ Type of Unit : __________________ Date of Last Alignment______ Running Sped : ___________________ KW:______________________ Coupling : Manufacturer ___________ Type: _____________________ Coupling Manufacturers tolerances : Angular ________Parallel _________ Notes:___________________________________________________ ____ ________________________________________________________ ____ Coupling Bracket I.D.: ______________ Bracket Deflection: __________ Movable Machine: _________________ Stationary Machine: _________ Lesson 4 Page 3 43. MACHINE ALIGNMENT REVERSE INDICATOR METHOD Fig. 4-2. Alignment Record Sheet. Lesson 4 Page 4 44. MACHINE ALIGNMENT REVERSE INDICATOR METHOD Fig. 4 -2. Position of Brackets Viewer. 3.10 CORRECT FOR SAG From previous discussions we know that indicator bracket sag only directly affects the bottom OD reading. We also know that it is a negative value. To correct for sag we simply subtract it, algebraically, from the bottom OD reading. Each bracket has a different value for sag and each must be handled independently. Lesson 4 Page 5 45. MACHINE ALIGNMENT REVERSE INDICATOR METHOD 4.0 USING ANALYTICAL METHOD FOR CALCULATING SHIMS (FOLLOW THE FIG. 4 -4) Fig. 4 -4. Sample diagram of reading and shaft positions. Lesson 4 Page 6 46. { } x D { } x D { } x D { } x D MACHINE ALIGNMENT REVERSE INDICATOR METHOD 4.1 VERTICAL MOVEMENT BA is the bottom reading at coupling A BB is the bottom reading at coupling B D1 is the distance between couplings D2 is the distance between coupling A and front support feet of movable machine.. D3 is the distance between coupling A and back support feet of moveable machine Now:- i. The shim correction required at front support feet. BA + BB 2 2 D1 - BA 2 ii. The shim correction require at back support feet. BA + BB 3 2 D1 - BA 2 4.2 HORIZONTAL MOVEMENT Normally for the horizontal alignment, no need of calculation but if machine is large and have jack bolts then this calculation is helpful for accurate horizontal movement. For horizontal movement dial set ZERO at left side and take the reading on the right side of the coupling. * RA is the right side reading on coupling A * RB is the right side reading on coupling B iii. Movement required at front support feet. RA + RB 2 2 D1 - RA 2 iv. Movement required at back support feet RA + RB 3 2 D1 - RA 2 Lesson 4 Page 7 47. } x 12 MACHINE ALIGNMENT REVERSE INDICATOR METHOD Example: Fig. 4 -5. Fig. 4 -5. VERTICAL MOVEMENT Shim correction required at front support feet. { BA + BB 2 } x D2 D1 - BA 2 BA = -10 BB = + 20 D1 = 8 D2 = 12) D3 = 24 { 10 + 20 2 8 - (-10) 2 10 2 x 12 8 + 5 = 12.5 Add 12.5 Thou shims at front support feet. Shim correction required at back support feet. { BA + BB 2 } x D3 D1 - BA 2 Lesson 4 Page 8 48. } x 24 { } x D } x 12 { } x D } x 24 MACHINE ALIGNMENT REVERSE INDICATOR METHOD { 10 + 20 2 8 - (-10) 2 10 2 x 24 8 + 5 = 20 Add 20 thou. Shims at back support feet. Movement required at front support feet = RA = R - L = -15 - (+5) = - 20 RB = R - L = 6 - 14 = -8 RA + RB 2 2 D1 - RA 2 { (20) + (-8) 2 28 2 x 8 - 12 8 + 10 (-20) 2 = -21 + 10 = -11 Move 11 thou. Towards right. Movement required at back support feet = RA + RB 3 2 D1 - RA 2 { (20) + (-8) 2 28 2 x 8 - 24 8 + 10 (-20) 2 = -32 Move 32 thou. Towards right. Lesson 4 Page 9 49. MACHINE ALIGNMENT REVERSE INDICATOR METHOD 5.0 ALIGNMENT PROCEDURE Outline of Alignment Procedure Step 1: Familiarize with terms, techniques and procedure. *follow all safety rules and procedures* Step 2: Learn about the machine you are aligning. a. Visually check coupling, pipehangers, base bolts, coupling spacing etc. b. Check for coupling & shaft run out. Step 3: Know the characteristics of your tool. Perform a Sag Check Step 4: Prepare the machine. a. Remove all existing shims from under the feet-if old shims are to be used, clean them thoroughly. -always use minimum amount of shims. b. Clean the base thoroughly. -scrape and file away all rust, nicks, and burrs c. Examine the base bolts and holes.-retap if necessary - replace bolts if necessary Step 5: Installation of alignment brackets a. Clean mounting surface, file off nicks and burrs. b. Check indicators for sticking and loose needle. c. Aim indicator stem directly toward center line of shaft. Step 6: Measurement - measure distance between the two indicators - measure distance between indicator and front feet. - measure distance between front and back feet. Step 7: Layout graph paper - mark indicator position - mark feet position. - remember to mark + and - signs (this eliminates confusion) example: graph layout Lesson 4 Page 10 50. MACHINE ALIGNMENT REVERSE INDICATOR METHOD Step 8: Preliminary Horizontal Move Step 9: Check for Soft Foot Step 10: Perform Vertical Move Step 11: Tighten all bolts and recheck indicator readings. Step 12: Remove alignment brackets. 6.0 LEARNING HOW TO GRAPH PLOT Graphical alignment is a technique that shows the relative position of the two shaft centerlines on a piece of square grid graph paper. First we must view the equipment to be aligned in the same manner that appears on the graph plot. In this example we view the equipment with the "FIXED" on the left and the "MOVEABLE" on the right. This will remain the same view both vertically and horizontally. Lesson 4 Page 11 51. MACHINE ALIGNMENT REVERSE INDICATOR METHOD Scale: Each Square = 1.0" Scale: Each Square = .001" Measure: A. Distance between indicators = 10" B. Distance between indicator and front foot = 5" C. Distance between feet =11" To eliminate confusion the plus and minus signs should be marked on the graph. Graph paper layout 7.0 VERTICAL MOVE Lesson 4 Page 12 52. MACHINE ALIGNMENT REVERSE INDICATOR METHOD The vertical move is the part of the alignment process that aligns the two shaft's centerlines nto their proper up and down position. Usually you will have to add or remove shims in this step. The indicators are zeroed on the top and read at the bottom. (start with a plus + reading if you need to compensate for sag) Example: the indicator on the motor pump -12 the indicator on the motor reads +8 This means that the shafts are one half the total indicator reading from being collinear at these points. Using a square grid graph paper to illustrate the position. Under the indicator position mark the point that is half the indicator reading. ( -6 for pump side indicator and +4 for the motor side indicator) Connect these two points with a line and then continue the line past the lines representing the feet on the motor. The graph now shows that the front foot needs to have a .003" shim added and the back foot needs to have a .001" shim added. Now with your shims in place. Tighten all bolts and take and check your readings. If the readings are within tolerance than your equipment should be aligned. Lesson 4 Page 13 53. MACHINE ALIGNMENT REVERSE INDICATOR METHOD 8.0 HORIZONTAL MOVE The horizontal move is the part of the alignment process that aligns the shaft's centerlines from side to side. View the machine from the pump end, zero the indicators on the left, and then rotate and read on the right. Make sure that you always view the pump from the same direction in order for you to keep the left and right directions correct. There is no sag compensation on the horizontal move. For example: the indicator on the pump reads 8 the indicator on the motor reads +10 The shafts are collinear at 1/2 the Total Indicator Reading. Using graph paper to illustrate the position. Under the indicator position mark the point that is 1/2 the indicator reading. (-4 for the pump and +5 for the motor) Connect these points and extend the line past the motors feet. This will show you how much you need to move the motor for horizontal alignment. These indicator readings mean that you need to move the motor: front foot .006" left back foot .007" left Lesson 4 Page 14 54. MACHINE ALIGNMENT REVERSE INDICATOR METHOD You can avoid graphing the horizontal move by zeroing the indicators on the left and rotate them to right. Now turn the indicator needles half way to zero and begin to walk the motor into place by moving the fartherest foot toward zero and then the nearest foot. Slowly walk the motor into place by alternating the moves until you obtain two zero indicator readings. Now begin the procedure for the vertical move. Be sure to check your equipment for sag and soft foot. Lesson 4 Page 15 55. Machine alignment Reverse Alignment Method With Thermal Growth LESSON 5 LECTURE REVERSE ALIGNMENT METHOD WITH THERMAL GROWTH ALLOWANCES AND TEMPERATURE GROWTH FACTORS Objectives To perform alignment by reverse indicator method taking into account different thermal position or growth factor calculation. 1.0 REVERSE ALIGNMENT METHOD Before the machines can be successfully aligned, the desired Ambient Condition positions must be determined. Once both the present and Desired readings are ascertained, the necessary vertical and horizontal moves can be computed. Although the corrective adjustment may be plotted on suitable graph paper, mathematical computations offer greater accuracy. However, for demonstration purposes, both methods will be used in the following example. 2.0 CALCULATING THE ADJUSTMENTS 2.1 DESIRED STATE OFFSET INDICATOR READINGS AT AMBIENT CONDITIONS Readings recommended by the manufacturer necessary to compensate for thermal movement, in hopes of achieving collinear alignment at normal service condition. Fig. 1-1 2.2 PRESENT STATE INDICATOR READINGS OBTAINED AT AMBIENT CONDITIONS Lesson 5 Page 1 56. Machine alignment Reverse Alignment Method With Thermal Growth Fig.1-2 2.3 ALIGNMENT LANGUAGE 1. Ambient Condition: A machine is considered to be at AMBIENT CONDITION when it is shutdown, blocked in, and hascooled until its temperature has equalized to atmospheric conditions with lube oil on. 2. Service Conditions: A machine is considered to be at SERVICE CONDITION when it is stabilized at its normal operating condition. 3. Collinear Alignment: A machine is con. sidered to be COLLINEAR ALIGNED when the shafts are in the same straight line (no misalignment). 4. Offset: Offset is the measured distance from the shaft center of one machine, to the projected center line of the second machine. Vertical offset is measured from top to bottom. Horizontal offset is measured from left to right. 5. Total Indicator Reading (TIR): The differential between two indicator readings obtained 1800 apart. When zeroed at the top and rotated 1800 to the bottom, the reading obtained is the vertical total indicator reading. If the indicator was zeroed at the left side and rotated 1800 to the right side, the reading obtained would be horizontal total indicator reading. The total indicator reading is always twice the offset. 6. Offset (TIR): Same as 4 above but expressed in total indicator readings. 7. Sweep Readings: The Sweep Readings are the readings obtained by sweeping the coupling 3600 with the dial indicator and noting readings at 900 intervals. The readings are taken at Top (T), Right (R), Bottom (B), and Left (L) of coupling being indicated. Lesson 5 Page 2 57. Machine alignment Reverse Alignment Method With Thermal Growth 8. Present State: A machine's present state is the bench mark of an alignment problem. This is the original misalignment at ambientcondition prior to making any corrections. 9. Desired State: A machine's desired state is the alignment target. This is the desired ambient condition alignment offset needed to compensate for the thermally - induced movement to be incurred between ambient and service conditions. 10. Final Readings: Readings obtained after the final adjustment has been made. 11. Indicator bracket sag is the amount of deflection by the indicator bracket attachment induced by gravity force. A correction for this deflection should be applied to the indicator readings SYMBOLS: T = Top of Coupling R = Right side of Coupling B = Bottom of Coupling L = Left side of Coupling TIR =Total Indicator Reading Vo = Vertical Offset Ho = Horizontal Offset V1 = Distance from the present to desired state of Mach B's projected CL at Coupling "A" V2 = Distance from Coupling "B's" present to desired state less V1 Note: V1 and V2 are only intermediate steps needed to form a working Triangle for calculations. = Near Foot of Machine B or the Nf Measured Point Nearest to the Coupling Ff = Far Foot of Machine B or the Measured point farthest from the Coupling Lesson 5 Page 3 58. Machine alignment Reverse Alignment Method With Thermal Growth D1 = Distance between the Indicator Planes, Plunger-to- Plunger. = The distance from the Indicator D2 Plane of Machine "A" to the Near Measured Point of Machine "B" (Nf) CL = Center Line CZ = Center Zone, Center of the Linear Zone of Proximeter Graph Curve. 2.4 MEASURED DISTANCES In order to graph or mathematically compute the correct adjustment needed to achieve the desired alignment, it will be necessary to establish three (3) measurements. These measurements are critical to the success of one move alignment and must be accurate to within 1/16 inch. 1. We must know the distance between the planes in which the dial indicator readings were taken (Plunger to Plunger). This distance is referred to as D1. 2. It is also necessary to know the distance from the indicator plane of machine A to the near adjustment plane of machine B . This is the distance between the indicator plane of Machine A to the near foot (Nf) of Machine B referred to as D2. 3. The distance between the indicator plane of A to the far adjustment plane is needed. This distance is referred to as D3 and is the distance between the indicator plane of Machine A to the far foot (Ff) of Machine B. Lesson 5 Page 4 59. Machine alignment Reverse Alignment Method With Thermal Growth Fig.1-3 2.5 ALIGNMENT MOVEMENTS The vertical and horizontal adjustment necessary to move Machine B from PRESENT to DESIRED relative position can be computed. The shim adjustment at the near foot (Nf) and far foot (Ff) can be determined in the vertical movement formula. The side to side movement at near foot (Nf) and far foot (Ff) can be determined in the horizontal movement formula. 1. Vertical Movement. V1 B3 B1 2 or (10) (36) 2 23 V2 B4 B2 2 V1or (20) (48) 2 (23) 11 N f V2 D2 D1 V1or 1112 8 (23) 40 At near Foot of "B", Add 0.040 Inch Shims Ff V2 D3 D1 V1or 11 24 8 (23) 56 At Far Foot of "B", Add 0.0.056 Inch Shims Lesson 5 Page 5 60. Machine alignment Reverse Alignment Method With Thermal Growth 2. Horizontal Movement. V1 (R3 L3 ) (R1 L1) 2 or (15) (5) (24) (12) 2 16 V2 (R4 L4 ) (R2 L2 ) 2 V1or [(6) (14)][(22) (26)] 2 (16) 22 N f V2 D2 D1 V1or 2212 8 (16) 17 At near Foot of "B", Move Right 0.017 0.040 Inch Ff V2 D3 D1 V1or 22 24 8 (16) 50 At near Foot of "B", Move Right 0.017 0.050 Inch Note: Observe all algebraic signs. If answer is plus, move machine B up or left. If answer is minus move machine B down or right. Fig.1- 4 Lesson 5 Page 6 61. Sag Machine alignment Reverse Alignment Method With Thermal Growth Fig.1- 5 Instructions for using the alignment specifications and worksheet. Each note in the discussion is indicated on the attached example by a circled number. 3.0 DETERMINING AMOUNT OF INDICATOR BAR SAG indicator bar sag can be determined by firmly affixing it to a sag free shaft mandrel, usually 4 inch diameter or larger, dependent on length. The mandrel may be supported between lathe centers, mounted on knife edges, or held and rotated by hand. With the indicator bar positioned on top of the mandrel, the sag of bar will be down toward the mandrel. Set indicator face to read zero at this position. By zeroing the indicator, you have errored the indicator by the amount of the sag. Rotate the mandrel 180 (indicator at bottom position). The indicator bar will sag away from the mandrel; hence the indicator reading will be twice the actual bar sag. TIR 2 Lesson 5 Page 7 62. Machine alignment Reverse Alignment Method With Thermal Growth Once the indicator bar sag is determined, it should be permanently stamped on the bar. This true sag must be accounted for when determining sweep readings. 4.0 CORRECTING BY THERMAL GROWTH FACTOR When machinery is operating the moving parts cause friction that in turn creates heat buildup causing the machinery to expand. This expansion in the machinery is called Thermal Growth. The amount of movement can be predicted when you know the machinery's material, temperature change, and the distance between shims and shaft centerline. 4.1 CALCULATING THERMAL MOVEMENT Fig.1-6 Growth = T x L x C Growth in mils T = Change in F L = Inches, shim to shaft center line C = Growth factor Example: T = 40 L = 14 C = 0.0063 T x L x C = Growth 40 x 13 x 0.0063 = 3.27 = 0.003 Lesson 5 Page 8 63. Machine alignment Reverse Alignment Method With Thermal Growth Growth Factors: 0.0126 = Aluminum 0.0100 = Bronze 0.0059 = Cast Iron 0.0074 = Stainless 0.0063 = Mld Steel 4.2 GRAPHING THERMAL MOVEMENT Most machinery must be misaligned cold so that the shafts will be collinear during normal operating conditions. Graphing the move above shows us that the pump does not move (no change in temperature) and the motor rises an estimated .003" (3 mils). Fig.1-7 Pump stays the same Motor rises .004" at both feet Lesson 5 Page 9 64. Machine Alignment Vertical Pump Alignment LESSON 6 LECTURE VERTICAL PUMP ALIGNMENT DETAILED PROCEDURE BY CALCULATION Objectives The objective of this module is to make students understand the basic concept and procedure of vertical pump alignment. 1.0 IMPORTANT FUNDAMENT POINTS FOR VERTICAL ALIGNMENT Please note down following points to understand and perform vertical pump alignment. a. In vertical pumps we will only add the shim to correct angular misalignment and we will make correction of angular misalignment in two planes. b. The angular correction is done with the help of simple relation between distance from centre of bolt hole to centre of opposite bolt hole of flange, coupling diameter, correction shim required and angular reading (difference of gap between coupling hubs top and bottom). c. You should go through the derivation of angular correction formula. d. It should be noted that when we make angular correction it will change the radial position. e. The change of radial alignment or position can be calculated easily by another relation which is between correction shim thickness, flange diameter where shims are added, angular reading and distance between shimming point to coupling hub face. Check the figure and derivation. There is also example of solved problem. Remember we select two planes for angular correction. 1.1 VERTICAL PUMP ALIGNMENT AND EFFECT OF VERTICAL ANGULAR CORRECTION ON RADIAL POSITION. See fig 1 Y is the distance between flange opposite bolts centers. X is the shim required for angular correction . Lesson 6 Page 1 65. Machine Alignment Vertical Pump Alignment C is coupling diameter change due to shim x added. b is distance from shimming point to coupling hub face. R is the shift in radial position(radial alignment) By geometry of triangles we can get the simple relation as given below. See fig 1 A/C=X/Y X(angular correction shim required)=A/C * Y R/b=X/Y R(radial position shift)=X/Y * b For angular alignment Shim required = Angular reading x Distance between opposite bolts of flange . Coupling Diameter Radial alignment position change due to angular correction . = Shim Added x distance between shimming point and coupling hub face. Distance Between opposite bolts holes centers of flange Y X b C A R Fig. 1-6 Lesson 6 Page 2 66. Machine Alignment Vertical Pump Alignment 1.2 EFFECT OF ADDING SHIMS (FOR FACE CORRECTION) ON RADIAL READINGS IN VERTICAL PUMPS See figure 2. Flange DD position shifts to position DD and Shaft YA shifts to new position YA . B = G . W DD B = G*W DD W = Distance from shimming point to coupling hub G = correction shim thickness. DD = Distance between opposite bolts holes centres of flange B = Change in radial position. Point(A) shifts to Point (A) D G Shimming Distance YDD Shifts To DD W YA Shifts To YA A B A D D Fig 2-6 Lesson 6 Page 3 67. +2 A +6 DD = 22 Machine Alignment Vertical Pump Alignment SOLVED EXAMPLE E . 0 D +8 ANGULAR READING IS.D = 0.001 Coup Dia = 6 Distance Between Flange and Coupling Hub = 20 DD 22 E FLANGE C D 6 20 20 A Fig3-6 Lesson 6 Page 4 68. Machine Alignment Vertical Pump Alignment VERTICAL PUMP ALIGNMENT CALCULATION. Shim reqd at D = 4 x 22 = 14.65 thous or mils. 6 Shim reqd at E = 8 x 22 = 29.28 mils. 6 When we put shim of 14.65 mils at D we will also need to put shim of 14.65/2 at E and E (which is 7.3 mils) so that there is no soft footness or gap. When we put shim of 29 mils at E we will also need to put shim of 29/2 mils shim at points D and D (which is 14.5 mils) So net result is: AT D = 14.65 + 29/2 = 14.65 + 14.5 = 29 mils AT D = 29/2 = 14.5 mils AT E = 295 + 14.5/2 = 36.3 mils AT E = 14.5/2 = 7.25 = 7 mils But if we remove shim of same size from all four positions which are D, D, E, E there will be no effect or change in alignment. So net shims reqd to be added at points D, D, E, E are: AT D = 29 7 = 22 mils AT D = 14.5 7.2 = 7.3 = 7 mils AT E = 36.3 7.2 = 29 mils AT E = 7.25 7.2 = 0 mils Lesson 6 Page 5 69. Machine Alignment Vertical Pump Alignment DD 24 C 6 20 A Fig 4-6 Lesson 6 Page 6