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Articles: Alignment and Balancing

The Impact on Bearing Life of Overtensioned Belts

by Jeremy Davis and Hunter Golden

One of the leading causes of premature bearing failure can be attributed to overload and overstress conditions.  A common catalyst for this type of condition is improper belt tensioning.  Increasing the radial load on a bearing will drastically reduce the expected bearing life span and can be graphically illustrated as y=1/x (0<x<infinity).  In order to achieve optimal design expectations, procedure based, precision maintenance practices must be utilized.

The Truth Behind Misalignment Vibration Spectra of Rotating Machinery

By S. Ganeriwala, S. Patel, H. A. Hartung

1. Abstract

Misalignment is probably the most common cause of machinery malfunction. Considering the importance of alignment, the vibration spectra of alignment is not well documented. Various authors have reported different spectra. The goal of this research was to determine the unique vibration signature for misalignment at varying operating and design conditions such as speed, type and level of misalignment, coupling types and machinery dynamic stiffness. The SpectraQuest Machinery Fault Simulator™ was used in the study to create the varying mechanical conditions.

Tops-on/Tops-off Diaphragm Alignment

By Damian Josefsberg

There is more than meets the eye when performing a turbine diaphragm alignment. It is not as simple as lining up all of the diaphragm bottom halves against a common reference line. To perform a correct diaphragm alignment it takes a lot of information, calculations, and time. If you plan properly, use the correct techniques, and technology; you will save time on the diaphragm alignment process and have a virtually rub free start-up. This can shave days to weeks off of your shut down and cause your turbine to operate more efficiently, thus saving lost production and increasing turbine output.

Understanding the basics of balancing and measuring Techniques

By Gary K. Grim, Bruce J. Mitchell

Why Balance? All rotating components experience significant quality and performance improvements if balanced. Balancing is the process of minimizing vibration, noise and bearing wear of rotating bodies. It is accomplished by reducing the centrifugal forces by aligning the principal inertia axis with the geometric axis of rotation through the adding or removing of material. In order to understand the basics of balancing it is necessary to define the following fundamental terms.

Vertical Condensate Pump Alignment

By Alan Luedeking
The shaft alignment of large vertical condensate pumps in power plants is a challenging application. The pump shaft and impeller are rigidly coupled to the vertical flange-mounted motor.

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