Gearbox alignment

Installation guidelines provided in the vendor s O M manual should be followed for proper installation of the gearbox housing and alignment to its mating machine-train components. 

Gearboxes must be installed on a rigid base that prevents flexing of its housing and the input and output shafts. Both the input and output shaft must be properly aligned, within 0.002 inch, to their respective mating shafts. Both shafts should be free of any induced axial forces that may be generated by the driver or driven units. 

Dial gauges for checking alignments of machines (specially high speed) coupled to gearboxes and motors ... 

Whether steam turbine, gearbox and generator are supphed as a pre-assembled unit on a common base plate or as separate units to be assembled at site. Alignment procedures and precautions should be asked for during procurement. 

Proper maintenance of the mechanical equipment and distribution system will ensure optimum operation from the cooling tower over a long period of time. Motors must remain properly lubricated, gearbox oil should be maintained at the proper level, and driveshaft alignment should be checked on a regular basis. Uniform distribution of hot water within the tower is essential in order to maintain optimum tower performance. Refer to Table 3.6 for a suggested preventive maintenance schedule for key tower components. 

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)... 

Poor maintenance practices are the primary source of real misalignment problems. Proper alignment of gear sets, especially large ones, is not an easy task. Gearbox manufacturers do not provide an easy, positive means to assure that shafts are parallel and that the proper center-to-center distance is maintained. 

Integral feed throats improve alignment between the barrel and gearbox, because one connection point has been eliminated. 

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