Handbook Of Shaft Alignment Episode 3 Part 4 docx

42 in. 16 in. 22 in. 70 in. Motor B Drive roll B Idler roll Motor A Drive roll A 40 in. Optical scale target Photodiode or 10 in. 10 in. 10 in. 10 in. 0 5 0 1 0 4 0 2 0 3 0 + _ 1 0 4 0 2 0 3 0 0 5 0 1 0 4 0 2 0 3 0 + _ 1 0 4 0 2 0 3 0 0 5 0 1 0 4 0 2 0 3 0 + _ 1 0 4 0 2 0 3 0 0 5 0 1 0 4 0 2 0 3 0 + _ 1 0 4 0 2 0 3 0 View looking east FIGURE 20.32 Side view of rolls and the drive motors. Motor B Drive roll B Idler roll Motor A Drive roll A East North FIGURE 20.33 Top view of rolls and the drive motors. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C020 Final Proof page 660 27.9.2006 1:30am 660 Shaft Alignment Handbook, Third Edition Motor A to drive shaft − 80 W Sag compensated readings − 170 Roll A to drive shaft +160 Sag compensated readings −80 Motor B to drive shaft Roll B to drive shaft +90 −31 +55+35 −49 Drive roll B Idler roll Drive roll A North target South target 200 mils high 15 mils to the east Reference 180 mils lower 27 mils to the west Reference 65 mils lower 25 mils to the east Reference North target South target North target South target Shaft alignment information Roll alignment information “Front side” face readings Face reading diameter = 10 in. Motor boundary condition information Roll boundary condition information Drive roll B Idler roll Drive roll A North bearing 80 mils of shims 30 mils east 70 mils west South bearing 40 mils of shims 70 mils east 35 mils west North bearing 40 mils of shims 57 mils east 42 mils west South bearing 250 mils of shims 70 mils east 37 mils west North bearing 140 mils of shims 15 mils east 105 mils west South bearing 110 mils of shims 100 mils east 22 mils west Motor B North bolts 160 mils of shims 95 mils east 10 mils west South bolts 90 mils of shims 0 mils east 85 mils west Motor A North bolts no shims 85 mils east 0 mils west South bolts 110 mils of shims 35 mils east 55 mils west T B E W 0 T B E −90 0 T B +85 WE +75 0 T B E W 0 FIGURE 20.34 Shaft alignment, roll alignment, and boundary condition information. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C020 Final Proof page 661 27.9.2006 1:30am Parallel Alignment 661 10 in. Scale: 200 mils or 10 in. Up Side view Motor A Roll A Motor B Roll B Idler roll Baseplate or frame restriction points Looking east FIGURE 20.35 Side view of roll drive system. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C020 Final Proof page 662 27.9.2006 1:30am 662 Shaft Alignment Handbook, Third Edition 10 in. Scale: 50 mils or 10 in. East Top view Motor A Roll A Motor B Roll B Idler roll Lateral movement restriction points FIGURE 20.36 Top view of roll drive system. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C020 Final Proof page 663 27.9.2006 1:30am Parallel Alignment 663 10 in. Scale: 200 mils or 10 in. Up Side view Motor A Roll A Motor B Roll B Idler roll Baseplate or frame restriction points Looking east Add 80 mils Pivot Pivot Add 110 mils Remove 95 mils Remove 110 mils Add 290 mils Remove 80 mils Pivot Remove 180 mils FIGURE 20.37 (See color insert following page 322.) Side view alignment model showing one possible solution. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C020 Final Proof page 664 27.9.2006 1:30am 664 Shaft Alignment Handbook, Third Edition 10 in. Scale : 50 mils or 10 in. East Top view Motor A Roll A Motor B Roll B Idler roll Lateral movement restriction points 35 mils west Pivot 22 mils east Pivot 20 mils west Pivot 50 mils west Pivot 60 mils west Pivot FIGURE 20.38 (See color insert following page 322.) Top view alignment model showing one possible solution. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C020 Final Proof page 665 27.9.2006 1:30am Parallel Alignment 665 Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C020 Final Proof page 666 27.9.2006 1:30am 21 Alignment Considerations for Specific Types of Machinery Up to this point, fairly broad generalizations have been made about rotating machinery. The shaft alignment measurement methods and tools discussed in Chapter 10 through Chapter 15 did not mention any specific type of machinery that the methods should be used on. Intentionally so, since most of these methods can be used on any type of machinery regardless of their specific function. The rotating equipment could have been electric motors, steam turbines, pumps, fans, compressors, or whatever. It really does not matter. The examples of graphing and modeling techniques covered in Chapter 8 through Chapter 20 had specific machine names on the diagrams, but for all practical purposes, the names of the machinery were not relevant, only the graphing concepts. The OL2R methods discussed in Chapter 16 should work on virtually any type of machinery but certain OL2R methods are better suited for certain situations than some of the others mentioned. This is not to suggest however that a wide variety of rotating machinery behaves the same way or should be aligned the same way. It is important to know a considerable amount of information about each piece of machinery before, during, and after the alignment process. Knowledge about how it works internally, what operational function does it perform, how does the process affect its operational performance, and how it interacts with its frame and foundation, and influence from external connections such as piping are important in thor- ough understanding of the behavior of the machine. The example in Appendix A illustrates the type of information that should be kept on each piece of rotating machinery. This chapter will explore some of the specific information relating to alignment on common rotating machinery equipment. Much of the information contained herein is based on actual field measurements but should not be construed as hard and fast rules. Always consult the manufacturer of the specific type of rotating machinery for information pertaining to your particular machine. But above all, do your own investigative analysis and learn the behavior of your machines. Most of the OL2R movement ranges indicated in each machine category are based on actual field measurements. These data indicate how the centerline of rotation of the shaft might move from OL2R (or how the inboard and outboard bearing positions change from OL2R and vice versa). The OL2R movement amounts reflect average ranges of motion; in other words, the high end values could, and in many cases, have been in excess of the numbers indicated, sometimes by a factor of 300% and up. Again, most manufacturers of rotating machinery do not conduct OL2R measurements at a customer’s plant site. If you consult the original equipment manufacturer for OL2R information, ask how the measurements were taken, what the environmental and operational conditions were during the test, and why they feel these data would be indicative of the machinery you have in operation. The following information is an attempt to give you an overview of what to consider when installing and aligning these different types of machinery. It is therefore recommended that Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C021 Final Proof page 667 6.10.2006 12:19am 667 this information be used strictly as a starting point for you to initially align new rotating machinery systems to allow you the opportunity to safely conduct field studies on your rotating equipment. 21.1 DRIVERS 21.1.1 E LECTRIC MOTORS Electric motors (AC induction or synchronous or DC motors) are perhaps the best behaved types of rotating machinery from an alignment standpoint. Electric motors up to 500 hp frequently are outfitted today with antifriction-type bearings so they do not pose any major installation problems assuming they are mechanically and electrically sound (Figure 21.1). Medium to large electric motors are frequently outfitted with sliding-type bearings (Figure 21.3). When power is applied to motors where the armatures are supported in sliding-type bearings, the electromagnetic field wants to center the rotor with respect to the stator field. This phenomenon is often referred to as ‘‘magnetic center’’ and needs to be taken into consideration for proper shaft-to-shaft spacing. Many electric motors have no thrust bearing per se and rely on electromagnetic forces to center the rotor. To find magnetic center, uncouple the motor and run it ‘‘solo.’’ Once the field is applied, you may notice the shaft ‘‘hunting’’ back and forth axially for a short period of time and then it will typically settle out at one specific axial position. Very carefully scribe a line on the rotating shaft with a felt tip pen or soapstone near a stationary reference fixture such as the bearing seal. Keep your fingers away from keys or keyways and do not let any loose clothing, tools, rags, or other stationary objects attached to your body or near you hit the shaft. Drop the field (i.e., shut the motor off) and let the rotor stop completely. It is unlikely that the shaft’s axial position is directly on magnetic center so after safety tagging the breaker, hand rotate the shaft pushing or pulling it axially until the scribe mark you made lines back up with the stationary reference fixture you picked. Now measure and set the shaft-to-shaft distance with the machine it is driving. FIGURE 21.1 Typical small electric motor. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C021 Final Proof page 668 6.10.2006 12:19am 668 Shaft Alignment Handbook, Third Edition If misalignment conditions are severe enough on electric motors and the shaft or armature elastically bends a sufficient amount, the rotor to stator air gap can get out of tolerance (the accepted tolerance for air gap eccentricity differential is +10% of the total air gap). From a vibration standpoint, eccentric air gap problems will frequently exhibit a spectral peak at twice line frequency (120 Hz in North America refer to Section 2.2.3). Typical OL2R movement range of electric motors (horizontally mounted): Vertical movement: 1 to 5 mils upward (5 to 200 hp); 3 to 30þ mils upward (200þ hp), typically symmetrical (i.e., inboard and outboard ends move up the same amount) Lateral (sideways) movement: 0 to 4 mils (usually much less than vertical movement) Axial movement: 5 to 10 mils (5 to 200 hp); 8 to 50þ mils (200þ hp) FIGURE 21.2 Medium size electric motor. FIGURE 21.3 Large electric motor supported in sliding bearings. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C021 Final Proof page 669 6.10.2006 12:19am Alignment Considerations for Specific Types of Machinery 669 [...]... 21.25 Alignment readings taken at the bottom of the pump shaft just above the stuffing box Piotrowski / Shaft Alignment Handbook, Third Edition DK 43 2 2_C021 Final Proof page 6 84 6.10.2006 12:19am 6 84 Shaft Alignment Handbook, Third Edition Adjustment nut 0 N +50 W E − 53 S 0 Balance ring 0 N + 54 W E − 53 S +4 Pump shaft 0 N +58 W E 49 S + 14 As-found alignment readings 14 in 5.5 in 4 in 30 20 40 10 30 20... 2 3 5 8 1 1 1 1 8 5 2 0 11 2 2 1 2 14 15 15 1 3 1 0 6 3 2 3 4 5 5 4 3 West I 11 mils J 8 mils H 13 mils K 4 mils 51 mils west 3 mils south G 13 mils South 1 mil North Note: Highest offset 0 mil F 12 mils 10 mils E 1 mil 6 mils D L A B 3 mils East C FIGURE 21.29 Shims to correct the angular misalignment and translations to correct the offsets Piotrowski / Shaft Alignment Handbook, Third Edition DK 43 2 2_C021... bushing of the pump Piotrowski / Shaft Alignment Handbook, Third Edition DK 43 2 2_C021 Final Proof page 6 83 6.10.2006 12:19am Alignment Considerations for Specific Types of Machinery 6 83 FIGURE 21. 24 Alignment readings taken at the top of the pump shaft at the adjustment nut the eccentricity and determine where the actual centerline of rotation of the pump shaft is as shown in Figure 21.26 The top part of. .. 132 105 96 128 132 1 03 139 88 96 115 100 121 108 92 70 85 97 82 60 64 107 92 53 34 60 78 50 32 50 50 50 FIGURE 21.10 Soft foot map between engine frame and soleplates on biogas engine shown in Figure 21.9 2 2 10 3 52 78 50 20 North 20 20 2 20 5 5 5 2 3 2 10 5 5 2 2 5 5 10 5 5 3 5 Piotrowski / Shaft Alignment Handbook, Third Edition DK 43 2 2_C021 Final Proof page 675 6.10.2006 12:19am Alignment Considerations... W Pump shaft E 0 .38 5 in gap S 0 .39 9 in gap FIGURE 21 .33 Measured clearances between the pump shaft extension and the hollow motor shaft Piotrowski / Shaft Alignment Handbook, Third Edition DK 43 2 2_C021 Final Proof page 688 6.10.2006 12:19am 688 Shaft Alignment Handbook, Third Edition 1 mil 1 mil 5 mils 1 mil 2 mils 1 mil FIGURE 21 . 34 Measured runout at several points along the exposed pump shaft, threaded... 02 03 Pump shaft measurement plane FIGURE 21.27 (See color insert following page 32 2.) As-found alignment model of motor and pump shaft as viewed in the north to south direction Piotrowski / Shaft Alignment Handbook, Third Edition DK 43 2 2_C021 Final Proof page 685 6.10.2006 12:19am 685 Alignment Considerations for Specific Types of Machinery Motor shaft centerline 180 wide ϫ 100 tall grid East 30 .4 in... Considerations for Specific Types of Machinery 675 Piotrowski / Shaft Alignment Handbook, Third Edition DK 43 2 2_C021 Final Proof page 676 6.10.2006 12:19am 676 Shaft Alignment Handbook, Third Edition FIGURE 21.11 Inside dial gauge used to measure web deflection –1 /4 +1 /4 5 1 –1 /4 4 2 +1 /4 3 0 FIGURE 21.12 Web deflection measurements typically taken at five positions FIGURE 21. 13 Single-stage centrifugal pumps... runout) 02 03 12 mils TIR here 01 04 05 + 0 _ 01 04 20 30 30 10 50 _ 0 + 40 10 Adjusting nut measurement plane Balance ring measurement plane 40 20 02 03 11 mils TIR here eter circle diam C–J bolt plane add 5 mils 4 in Actual pump shaft centerline of rotation (i.e., compensated for runout) Scale: 5 in and 10 mils 0 S N 0 Balance ring +4 S N 0 Pump shaft + 13 02 01 04 05 + 0 _ 01 04 6 mils TIR here 03 5 in... Alignment Handbook, Third Edition DK 43 2 2_C021 Final Proof page 686 6.10.2006 12:19am 686 Shaft Alignment Handbook, Third Edition Soft foot map 2 I 2 West 3 3 J 0 0 H 2 K 2 2 2 L G 2 South 2 2 North 4 A F 3 4 B 0 0 7 E 7 8 D8 East C 3 4 FIGURE 21 .30 Soft foot gap measurements at all the flange bolts Notice that there is a greater amount of angular misalignment in the north–south direction than the east–west... specified distance between the end of the motor shaft and the end of the pump shaft was 0.250 in There is an adjustment nut on the top of the pump FIGURE 21.18 Large vertical pumps Piotrowski / Shaft Alignment Handbook, Third Edition DK 43 2 2_C021 Final Proof page 680 6.10.2006 12:19am 680 Shaft Alignment Handbook, Third Edition FIGURE 21.19 Vertical pump Angular location of high spot viewed from above . compressor. Piotrowski / Shaft Alignment Handbook, Third Edition DK 43 2 2_C021 Final Proof page 6 74 6.10.2006 12:19am 6 74 Shaft Alignment Handbook, Third Edition 52 60 60 78 78 64 50 50 53 20 32 34 70 76 76 85 89 77 97 107 108 82 92 92 96 100 96 115 121 128 132 132 139 1 03 105 88 50 3 2 2 10 5 50. in. 0 5 0 1 0 4 0 2 0 3 0 + _ 1 0 4 0 2 0 3 0 0 5 0 1 0 4 0 2 0 3 0 + _ 1 0 4 0 2 0 3 0 0 5 0 1 0 4 0 2 0 3 0 + _ 1 0 4 0 2 0 3 0 0 5 0 1 0 4 0 2 0 3 0 + _ 1 0 4 0 2 0 3 0 View looking east FIGURE 20 .32 Side view of rolls and the. 20 . 34 Shaft alignment, roll alignment, and boundary condition information. Piotrowski / Shaft Alignment Handbook, Third Edition DK 43 2 2_C020 Final Proof page 661 27.9.2006 1 :30 am Parallel Alignment