Shaft alignment

Pump shaft and driver shaft alignment is very important for long useful equipment life, and to extend the running time between repairs. Besides, good alignment reduees the progressive degradation of the pump. 

The shaft alignments are automatically entered into a small computer that calculates the relative required movements needed at the motor base to align the two shafts. Sec Figure 10-9. 

Soft-foot is the condition when all four of a machine s feet do not support the weight of the machine. It is important to determine if this condition is present prior to performing shaft alignment on a piece of machinery. Not correcting soft-foot prior to alignment is a major cause of frustration and lost time during the aligning procedure. 

As shown by the above examples, the correct use of positive (4-) and negative (—) signs is important in shaft alignment. 

The last step in the installation process is verifying coupling and shaft alignment. With the exception of special application couplings such as spindles and jackshafts, all couplings must be aligned within relatively close tolerances (i.e., 0.001-0.002 inch). 

Provision shall be made for the attachment of shaft alignment equipment without the need to remove the spacer or dismantle the coupling in any way. 

Shaft Alignment Handbook Second Edition, Revised and Expanded, John Piotrowski... 

Loading shaft —— Alignment collar j Top plate Steel ball... 

Shaft alignment is very critical. The centerline of the shafts must be within 0.002 in. between top and bottom. The drive side shoulders should be within 0.0005-tenths of an inch top to bottom, they should be within 0.001 in. from one station to the next and they should be within 0.005 in. from the beginning to the end of the machine. Last but not least, the shafts must be parallel top to bottom within 0.0005-tenths of an inch. They must be square to each other—station to station—within 0.002 in. 

Figure 2 Shaft Alignment. Machine alignment is a must for holding shape tolerances and optimum roll life. Alignment of shoulders from stand to stand is also important, however, larger tolerances can be accommodated.

Mechanical equipment Fan blade damage, unbalance, pitch, fan shaft looseness, speed reducer wear, shaft alignment Make checks and corrections as necessary. 

Servo Systems (concepts and purpose, type motors and variations, explanations and applications of direct, gearbox and screw motor-to-load coupling, motor and encoder shaft alignments, servo system concepts, servo tuning, servo profiles)... 

Piotrowski, J. 2007. Shaft Alignment Handbook, 3rd ed. Boca Raton CRC Press. This title deals with the narrow field of shaft alignment, a field crucial to the proper functioning of pumps, gears, turbines, fans, engines, compressors, etc. Particular emphasis is placed on measuring proper function and on techniques to correct misalignments. 

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