Handbook of Shaft Alignment Part 13 pdf

Gear Pump 10 in. Up Side view Scale : 30 mils T B EW 0 T B EW 0 PumpGear output +20 −66 −2 −68 −32 +52 Gear Pump Scale: East Top View 10 in. 50 mils T B EW T B EW PumpGear output 0 +64 0 +84 View looking east 24 in.48 in. 14 in.10 in. 1 in. Motor Gear 32 in. Pump 0 50 10 40 20 30 + _ 10 40 20 30 0 50 10 40 20 30 + _ 10 40 20 30 0 50 10 40 20 30 + _ 10 40 20 30 0 50 10 40 20 30 + _ 10 40 20 30 2 in. 28 in. 32 in. 0 50 10 40 + _ 10 40 20 30 0 50 10 40 20 30 + _ 10 40 20 30 FIGURE 17.9 Side and top view alignment models of just the gear and the pump. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 570 26.9.2006 8:41pm 570 Shaft Alignment Handbook, Third Edition Motor Gear 10 in. Up Side view Scale: Motor Gear Scale: East Top view 30 mils 10 in. 50 mils T B 0 T B EEWW 0 Motor Gear input − 50 − 40+70 +30 +20−70 T B T B EEWW Motor Gear input −1100+900 63 mils down 31 mils down 37 mils east 10 mils east FIGURE 17.10 Required moves to align the motor to the gear. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 571 26.9.2006 8:41pm Aligning Multiple-Element Drive Systems 571 Gear Pump 10 in. Up Side view Scale: 30 mils T B E 0 T B EW W 0 PumpGear output +20 −66 −2 −68 −32 +52 Gear Pump Scale: East Top view 10 in. 50 mils T B T B EEWW PumpGear output 0 +64 0 +84 63 mils down 93 mils down 120 mils east 220 mils east FIGURE 17.11 Required moves to align the pump to the gear. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 572 26.9.2006 8:41pm 572 Shaft Alignment Handbook, Third Edition Motor Gear 20 in. Up Side view Scale: Scale: East Top view 50 mils 10 in. 100 mils 63 mils down 31 mils down 37 mils east10 mils east Pump Motor Gear Pump FIGURE 17.12 Three-element alignment model showing the gear and motor shafts only. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 573 26.9.2006 8:41pm Aligning Multiple-Element Drive Systems 573 Motor Gear 20 in. Up Side view Scale: Scale: East Top view 50 mils 10 in. 100 mils 63 mils down 93 mils down Pump Motor Gear Pump 120 mils east 220 mils east FIGURE 17.13 Three-element alignment model showing all three shafts. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 574 26.9.2006 8:41pm 574 Shaft Alignment Handbook, Third Edition Figure 17.14 shows the misalignment between the motor and gear shafts in the side and top views using the line to points reverse indicator modeling technique. Figure 17.15 shows the misalignment between the gear and pump shafts in the side and top views. It does not matter which set of readings is plotted first, the motor to gear or the gear to pump. Notice that the Motor Gear 20 in. Up Side view Scale: Scale: East Top View 50 mils 10 in. 100 mils Pump Motor Gear Pump T B EW 0 T B EW 0 Motor Gear input −50 −40+70 +30 +20−70 T B EW T B EW Motor Gear input −1100+900 FIGURE 17.14 Three-element alignment model plotting the motor and gear shafts using the line to points reverse indicator modeling technique. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 575 26.9.2006 8:41pm Aligning Multiple-Element Drive Systems 575 Motor Gear 20 in. Up Side view Scale: Scale: East Top view 50 mils 10 in. 100 mils Pump Motor Gear Pump T B EW 0 T B EW 0 PumpGear output +20 −66 −2 −68 −32 +52 T B EW T B EW PumpGear output 0 +64 0 +84 FIGURE 17.15 Three-element alignment model plotting the gear and pump shafts using the line to points reverse indicator modeling technique. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 576 26.9.2006 8:41pm 576 Shaft Alignment Handbook, Third Edition positions of the shafts in Figure 17.13 are identical to the positions of the shafts in Figure 17.15 even though two different methods were used to generate the two graphs. Again, just as in modeling two-shaft drive systems, all that has been accomplished with the graph is that the positions of the shafts have been determined. At this point, it is imperative that the restrictions in the up or down and east or west directions be determined at every bolting plane on all three machines and transferred onto the graph. Once this has been done, the final desired overlay line can be drawn onto the graph and the movement solutions at all of the bolting or translation planes can be determined and executed. An example of this is illustrated in Figure 17.16 showing the amount of existing shims and the lateral movement restrictions at each bolting plane. Notice that in the side view if you were to name any one of the machines as a ‘‘stationary’’ machine, the vertical restriction would have prevented you from aligning the drive system; and in the top view if you were to name either the gear or the pump as a stationary machine, the lateral restriction would have prevented you from aligning the drive system. 17.5 MIXING DIFFERENT ALIGNMENT MEASUREMENT METHODS In some situations, more than one alignment measurement method could be (or may have to be) employed to measure each set of shafts. Figure 17.17 through Figure 17.19 show how you can use different alignment measurement methods and still model the machinery positions. Two electric motors are coupled together to drive a gearbox and a compressor. A laser– detector shaft alignment system was used to measure the alignment between the two motors (Motor A and Motor B). Reverse Indicator readings were taken between Motor B and the gearbox. The shaft to coupling spool method was employed between the gear output shaft and the compressor. Figure 17.17 shows the dimensions of the four-element drive system, the information gathered from the laser–detector shaft alignment system, the reverse indicator measurements (before and after sag compensation), the shaft to coupling spool measurements (before and after sag compensation), the amount of existing shims under each bolting plane, and the lateral movement restrictions at each bolting plane. You need every piece of infor- mation shown in Figure 17.17 to determine how to correct the misalignment condition that exists on this drive system. Figure 17.18 shows the side view alignment model of all four shafts and the vertical restriction boundary. The gear shafts were placed on the graph paper centerline and each shaft was referenced from the gear outward. Figure 17.19 shows the top view alignment model of all four shafts and the lateral restriction envelope. Again, the gear was placed on the graph paper centerline and each shaft was referenced from that point outward. Carefully study both alignment models to determine how the shafts were constructed. Despite the fact that three different alignment measurement methods and tools were used to determine the relative positions of each set of shafts, the entire drive train can still be modeled on graph paper. As you can see from the shaft positions in the side view, attempting to call Motor A, Motor B, or the gear as the ‘‘fixed’’ or stationary machine will result in a lot of headaches and unnecessary work. In the top view, attempting to call any of the four machines as the fixed or stationary machine will result in unforeseen situations and unneces- sary work. It should become obvious why it is recommended that the multiple-element drive train alignment laws mentioned above should be adhered to when aligning drive systems of this complexity. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 577 26.9.2006 8:41pm Aligning Multiple-Element Drive Systems 577 17.6 MODELING RIGHT-ANGLE DRIVE SYSTEMS So far, we have examined rotating machinery drive systems that are horizontally mounted, direct in-line machinery. But not all drive systems are configured that way. Some drive trains are arranged in an ‘‘L’’ shape, commonly referred to as right-angle drives. A right-angled Motor Gear 20 in. Up Side view Scale: Scale: East Top view 50 mils 10 in. 100 mils Pump Motor Gear Pump Lateral movement restriction points Baseplate restriction points Overlay line 38 mils up 47 mils up 45 mils down Pivot here Pivot here 25 mils down Overlay line No lateral moves required on motor 57 mils west 80 mils west 83 mils east Pivot here FIGURE 17.16 Possible alignment corrective moves after overlaying the boundary conditions. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 578 26.9.2006 8:41pm 578 Shaft Alignment Handbook, Third Edition Gear Motor A Compressor 62 in. 62 in. 50 in. 20 in. 10 in. 8 in. 10 in. 12 in. 8 in. Motor B 16 in. 4 in. Flex point Flex point 0 50 10 40 20 30 + _ 10 40 20 30 0 50 10 40 20 30 + _ 10 40 20 30 12 in. 14 in.12 in. 380" overall length from outboard bolts of Motor A to outboard bolts of compressor. Motor B Bracket sag = 6 mils Sa g compensated readings Field readings Gear to spool Compressor to spool 0 −30 –20 Bracket sag = 10 mils Sag compensated readings Field readings +60 A laser alignment system was used between Motor A and Motor B. With Motor A named as the stationary machine, the following moves on Motor B were indicated by the laser: lower “near” foot 40 mils raise “far” foot 15 mils move “near” foot 50 mils east move “far” foot 45 mils west −43 −23 T B E W 0 25 mils shims 60 east • 20 west 80 mils shims 80 east • 0 west 50 mils shims 40 east • 40 west 40 mils shims 16 east • 60 west 30 mils shims 30 east • 50 west No shims 60 east • 0 west Gear +14 +30 T B EW 0 T B EW 0 T B EW 0 T B EW 0 T B EW 0 T B EW 0 T B EW 0 View looking east −66 +44 −40 −20 +17 +33 −60 +50 −30 +40 +5 –25 –15 +65 –20 +50 0 50 10 40 20 30 + _ 10 40 20 30 0 50 10 40 20 30 + _ 10 40 20 30 FIGURE 17.17 Four-element drive system arrangement with all the required alignment information. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 579 26.9.2006 8:41pm Aligning Multiple-Element Drive Systems 579 [...]... apparent simplicity of these drives obscures the complexity of the misalignment condition that may exist Figure 18.17 shows the three basic types of misalignment that can occur: offset, pitch, and skew conditions Usually there is a combination of all three of these Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C018 Final Proof page 600 600 28.9.2006 7:15pm Shaft Alignment Handbook, Third... Four-element drive system side view alignment model of all four shafts and the lateral restriction envelope 20 in Scale: Motor A Top view Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 581 26.9.2006 8:41pm 581 Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 582 582 26.9.2006 8:41pm Shaft Alignment Handbook, Third Edition gearbox is... Final Proof page 603 Aligning V-Belt Drives FIGURE 18.15 Face runout check on sheave FIGURE 18.16 Bent sheave 28.9.2006 7:15pm 603 Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C018 Final Proof page 604 604 28.9.2006 7:15pm Shaft Alignment Handbook, Third Edition Offset—the shafts are parallel to each other and in the X−Y plane but one shaft/ sheave is to the right of left of the other shaft/ sheave... Right-angle drive system side view alignment model through the center of the right-angle gear through its vertical axis) The left side of the side view alignment model shows what the position of the motor shaft and input shaft of the gear would look like if you were looking to the east The right side of the side view alignment model shows what the position of the output shaft of the gear and the roll would... Figure 18.7 shows how to calculate the required length of a V-belt 591 Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C018 Final Proof page 592 592 FIGURE 18.1 Belt driven fan FIGURE 18.2 Belt driven fan 28.9.2006 7:15pm Shaft Alignment Handbook, Third Edition Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C018 Final Proof page 593 28.9.2006 7:15pm Aligning V-Belt Drives 593... can consist of up to 20 or more elements in ‘‘L’’ shapes, ‘‘U’’ shapes, ‘‘S’’ shapes, or other ridiculously complex arrangements Regardless of how many pieces of machinery are in the drive train or how the shaft- to -shaft measurements were taken, the positions of all the machinery can be accurately illustrated on Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 589 26.9.2006... Alignment Handbook, Third Edition DK4322_C018 Final Proof page 596 596 28.9.2006 7:15pm Shaft Alignment Handbook, Third Edition Belt length = 2C + 1.57 (D + d ) + (D − d )2 4C D d C Usually one of the machines has an adjustment for tensioning the belts Adjust the position of this machine so that it is in the center of its shaft separation travel FIGURE 18.7 How to determine the correct length of a belt... The goal is to align the centerline of rotation of the driver and the input shaft of the gear and the driven unit to the output shaft of the gear There are two tricks to this modeling method One is to plot the graph in the ‘‘dual scale’’ mode similar to the method used for face–rim plotting covered in Chapter 11 The other trick is to ‘‘fold’’ one of the views of the alignment model where the right angle... STRAIGHTEDGE TO MEASURE MISALIGNMENT Belt and sheave driven equipment poses a slightly different type of alignment problem than equipment directly coupled together The basic objective is to insure that the shaft centerlines are parallel to each other Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C018 Final Proof page 601 Aligning V-Belt Drives 28.9.2006 7:15pm 601 FIGURE 18 .13 Face runout check... which are typically aligned to around 1 mil=in Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C018 Final Proof page 602 602 28.9.2006 7:15pm Shaft Alignment Handbook, Third Edition FIGURE 18.14 Rim runout check on sheave Straightedges work fine for distances under 4 ft but when the distance between the driver shaft and the driven shaft begin to exceed that, a string should probably be used . east FIGURE 17 .13 Three-element alignment model showing all three shafts. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 574 26.9.2006 8:41pm 574 Shaft Alignment Handbook, . and top view alignment models of just the gear and the pump. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 570 26.9.2006 8:41pm 570 Shaft Alignment Handbook, . view alignment model of all four shafts and the vertical restriction boundary. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C017 Final Proof page 580 26.9.2006 8:41pm 580 Shaft Alignment